/**
 * Rox AI Admin Panel - Secure Administration Interface
 * @version 1.0.0
 * @description Production-ready admin panel with JWT auth and exact UI matching
 */
'use strict';

// ==================== CONSTANTS ====================
const API_BASE = '/admin/api';
const TOKEN_KEY = 'rox_admin_token';
const SESSION_TIMEOUT = 24 * 60 * 60 * 1000; // 24 hours

// HTML escape map for XSS prevention
const HTML_ESCAPE_MAP = { '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;', "'": '&#039;' };

// Superscript map for math expressions
const SUPERSCRIPTS = {
    '0': '⁰', '1': '¹', '2': '²', '3': '³', '4': '⁴',
    '5': '⁵', '6': '⁶', '7': '⁷', '8': '⁸', '9': '⁹',
    '+': '⁺', '-': '⁻', '=': '⁼', '(': '⁽', ')': '⁾',
    'n': 'ⁿ', 'i': 'ⁱ', 'x': 'ˣ', 'y': 'ʸ', 'a': 'ᵃ',
    'b': 'ᵇ', 'c': 'ᶜ', 'd': 'ᵈ', 'e': 'ᵉ', 'f': 'ᶠ',
    'g': 'ᵍ', 'h': 'ʰ', 'j': 'ʲ', 'k': 'ᵏ', 'l': 'ˡ',
    'm': 'ᵐ', 'o': 'ᵒ', 'p': 'ᵖ', 'r': 'ʳ', 's': 'ˢ',
    't': 'ᵗ', 'u': 'ᵘ', 'v': 'ᵛ', 'w': 'ʷ', 'z': 'ᶻ'
};

// Subscript map for math expressions
const SUBSCRIPTS = {
    '0': '₀', '1': '₁', '2': '₂', '3': '₃', '4': '₄',
    '5': '₅', '6': '₆', '7': '₇', '8': '₈', '9': '₉',
    '+': '₊', '-': '₋', '=': '₌', '(': '₍', ')': '₎',
    'a': 'ₐ', 'e': 'ₑ', 'h': 'ₕ', 'i': 'ᵢ', 'j': 'ⱼ',
    'k': 'ₖ', 'l': 'ₗ', 'm': 'ₘ', 'n': 'ₙ', 'o': 'ₒ',
    'p': 'ₚ', 'r': 'ᵣ', 's': 'ₛ', 't': 'ₜ', 'u': 'ᵤ',
    'v': 'ᵥ', 'x': 'ₓ'
};

// Language name mappings for code blocks
const LANGUAGE_NAMES = {
    'js': 'javascript', 'ts': 'typescript', 'py': 'python', 'rb': 'ruby',
    'sh': 'bash', 'yml': 'yaml', 'md': 'markdown', 'cs': 'csharp', 'cpp': 'c++'
};

// ==================== ADMIN PANEL CLASS ====================
class AdminPanel {
    constructor() {
        this.token = null;
        this.currentUser = null;
        this.currentChat = null;
        this.users = [];
        this.chats = [];
        this.stats = {};
        this.refreshInterval = null;
        
        this._init();
    }

    _init() {
        this._initElements();
        this._initEventListeners();
        this._initKeyboardShortcuts();
        this._checkAuth();
    }

    _initElements() {
        // Login elements
        this.loginOverlay = document.getElementById('loginOverlay');
        this.loginForm = document.getElementById('loginForm');
        this.passwordInput = document.getElementById('passwordInput');
        this.loginError = document.getElementById('loginError');
        this.loginAttempts = document.getElementById('loginAttempts');
        this.loginBtn = document.getElementById('loginBtn');
        
        // App elements
        this.app = document.getElementById('app');
        this.sidebar = document.getElementById('sidebar');
        this.sidebarOverlay = document.getElementById('sidebarOverlay');
        this.menuBtn = document.getElementById('menuBtn');
        this.mobileMenuBtn = document.getElementById('mobileMenuBtn');
        this.sidebarCloseBtn = document.getElementById('sidebarCloseBtn');
        
        // Stats elements
        this.totalUsers = document.getElementById('totalUsers');
        this.totalChats = document.getElementById('totalChats');
        this.todayQueries = document.getElementById('todayQueries');
        this.avgResponseTime = document.getElementById('avgResponseTime');
        this.totalMessages = document.getElementById('totalMessages');
        this.activeSessions = document.getElementById('activeSessions');
        this.modelUsageChart = document.getElementById('modelUsageChart');
        this.systemHealthChart = document.getElementById('systemHealthChart');
        
        // User list elements
        this.userList = document.getElementById('userList');
        this.userSearch = document.getElementById('userSearch');
        this.selectedUserName = document.getElementById('selectedUserName');
        
        // Chat elements
        this.chatsPanel = document.getElementById('chatsPanel');
        this.chatsPanelCloseBtn = document.getElementById('chatsPanelCloseBtn');
        this.chatsPanelOverlay = document.getElementById('chatsPanelOverlay');
        this.chatsList = document.getElementById('chatsList');
        this.chatView = document.getElementById('chatView');
        this.chatHeader = document.getElementById('chatHeader');
        this.chatTitle = document.getElementById('chatTitle');
        this.chatMeta = document.getElementById('chatMeta');
        this.messagesArea = document.getElementById('messagesArea');
        
        // Action buttons
        this.refreshBtn = document.getElementById('refreshBtn');
        this.exportBtn = document.getElementById('exportBtn');
        this.exportDropdown = document.getElementById('exportDropdown');
        this.exportJsonBtn = document.getElementById('exportJsonBtn');
        this.exportPdfBtn = document.getElementById('exportPdfBtn');
        this.exportUsersPdfBtn = document.getElementById('exportUsersPdfBtn');
        this.exportChatJsonBtn = document.getElementById('exportChatJsonBtn');
        this.exportChatPdfBtn = document.getElementById('exportChatPdfBtn');
        this.clearBtn = document.getElementById('clearBtn');
        this.logoutBtn = document.getElementById('btnLogout');
        this.lastUpdated = document.getElementById('lastUpdated');
        this.lastUpdateTime = null;
        
        // Tabs
        this.tabBtns = document.querySelectorAll('.tab-btn');
        this.usersTab = document.getElementById('usersTab');
        this.statsTab = document.getElementById('statsTab');
        
        // Dialog
        this.dialogOverlay = document.getElementById('dialogOverlay');
        this.dialogTitle = document.getElementById('dialogTitle');
        this.dialogMessage = document.getElementById('dialogMessage');
        this.dialogConfirm = document.getElementById('dialogConfirm');
        this.dialogCancel = document.getElementById('dialogCancel');
        
        // Help dialog
        this.helpOverlay = document.getElementById('helpOverlay');
        this.helpBtn = document.getElementById('helpBtn');
        this.helpClose = document.getElementById('helpClose');
        
        // Toast container
        this.toastContainer = document.getElementById('toastContainer');
        
        // Connection status
        this.connectionStatus = document.getElementById('connectionStatus');
        this.connectionDot = this.connectionStatus?.querySelector('.connection-dot');
        this.connectionText = this.connectionStatus?.querySelector('span');
        
        // Auto-refresh indicator
        this.autoRefreshIndicator = document.getElementById('autoRefreshIndicator');
        
        // Search results counter
        this.searchResultsCount = document.getElementById('searchResultsCount');
        
        // Chat count badge
        this.chatCountBadge = document.getElementById('chatCountBadge');
        this.chatCount = document.getElementById('chatCount');
        
        // Breadcrumb
        this.breadcrumb = document.getElementById('breadcrumb');
        
        // Performance indicators
        this.performanceIndicators = document.getElementById('performanceIndicators');
        
        // Trend elements
        this.usersTrend = document.getElementById('usersTrend');
        this.chatsTrend = document.getElementById('chatsTrend');
        this.todayTrend = document.getElementById('todayTrend');
        
        // Sparkline elements
        this.responseTimeSparkline = document.getElementById('responseTimeSparkline');
        this.messagesSparkline = document.getElementById('messagesSparkline');
        this.activityIndicator = document.getElementById('activityIndicator');
        
        // New enhanced stats elements
        this.peakHour = document.getElementById('peakHour');
        this.peakHourLabel = document.getElementById('peakHourLabel');
        this.onlineUsers = document.getElementById('onlineUsers');
        this.avgChatsPerUser = document.getElementById('avgChatsPerUser');
        this.serverInfoChart = document.getElementById('serverInfoChart');
        this.hourlyUsageChart = document.getElementById('hourlyUsageChart');
        
        // Summary elements
        this.summaryTotalUsers = document.getElementById('summaryTotalUsers');
        this.summaryOnline = document.getElementById('summaryOnline');
        this.summaryToday = document.getElementById('summaryToday');
        
        // Enhanced analytics elements
        this.yesterdayQueries = document.getElementById('yesterdayQueries');
        this.weekQueries = document.getElementById('weekQueries');
        this.monthQueries = document.getElementById('monthQueries');
        this.newUsersToday = document.getElementById('newUsersToday');
        this.newUsersWeek = document.getElementById('newUsersWeek');
        this.avgMessagesPerChat = document.getElementById('avgMessagesPerChat');
        this.dailyActivityChart = document.getElementById('dailyActivityChart');
        this.browserDistribution = document.getElementById('browserDistribution');
        this.osDistribution = document.getElementById('osDistribution');
        this.deviceDistribution = document.getElementById('deviceDistribution');
        this.languageDistribution = document.getElementById('languageDistribution');
        this.refererDistribution = document.getElementById('refererDistribution');
        this.countryDistribution = document.getElementById('countryDistribution');
        this.screenDistribution = document.getElementById('screenDistribution');
        
        // New enhanced elements
        this.realtimeOnline = document.getElementById('realtimeOnline');
        this.lastHourQueries = document.getElementById('lastHourQueries');
        this.returningUsers = document.getElementById('returningUsers');
        this.returningRate = document.getElementById('returningRate');
        this.totalPageViews = document.getElementById('totalPageViews');
        this.avgPageViews = document.getElementById('avgPageViews');
        this.avgSessionDurationEl = document.getElementById('avgSessionDuration');
        this.totalSessionsEl = document.getElementById('totalSessions');
        this.bounceRateEl = document.getElementById('bounceRate');
        this.newUsersMonthEl = document.getElementById('newUsersMonth');
        this.totalErrorsEl = document.getElementById('totalErrors');
        this.errorRateEl = document.getElementById('errorRate');
        this.recentErrorsEl = document.getElementById('recentErrors');
        this.totalTokensEl = document.getElementById('totalTokens');
        this.topUsersChart = document.getElementById('topUsersChart');
        
        // New enhanced elements
        this.avgEngagement = document.getElementById('avgEngagement');
        this.avgTimeOnSite = document.getElementById('avgTimeOnSite');
        this.mobilePercent = document.getElementById('mobilePercent');
        this.avgSessionsPerUser = document.getElementById('avgSessionsPerUser');
        this.weeklyHeatmap = document.getElementById('weeklyHeatmap');
        
        // User details panel
        this.userDetailsPanel = document.getElementById('userDetailsPanel');
        this.userDetailsContent = document.getElementById('userDetailsContent');
        this.closeUserDetailsBtn = document.getElementById('closeUserDetails');
    }

    _initEventListeners() {
        // Login form
        this.loginForm?.addEventListener('submit', (e) => this._handleLogin(e));
        
        // Logout
        this.logoutBtn?.addEventListener('click', () => this._logout());
        
        // Mobile menu
        this.menuBtn?.addEventListener('click', () => this._toggleSidebar());
        this.mobileMenuBtn?.addEventListener('click', () => this._toggleSidebar());
        this.sidebarCloseBtn?.addEventListener('click', () => this._closeSidebar());
        this.sidebarOverlay?.addEventListener('click', () => this._closeSidebar());
        
        // Chats panel mobile
        this.chatsPanelCloseBtn?.addEventListener('click', () => this._closeChatsPanel());
        this.chatsPanelOverlay?.addEventListener('click', () => this._closeChatsPanel());
        
        // Tabs
        this.tabBtns.forEach(btn => {
            btn.addEventListener('click', () => this._switchTab(btn.dataset.tab));
        });
        
        // User search with debouncing
        let searchTimeout;
        this.userSearch?.addEventListener('input', (e) => {
            clearTimeout(searchTimeout);
            const query = e.target.value;
            
            // Visual feedback for search
            if (query) {
                e.target.style.borderColor = 'var(--accent)';
                e.target.style.boxShadow = '0 0 0 3px rgba(62, 180, 137, 0.15)';
            } else {
                e.target.style.borderColor = '';
                e.target.style.boxShadow = '';
            }
            
            searchTimeout = setTimeout(() => {
                this._filterUsers(query);
            }, 300);
        });
        
        // Action buttons
        this.refreshBtn?.addEventListener('click', () => this._refreshData());
        this.exportBtn?.addEventListener('click', (e) => this._toggleExportDropdown(e));
        this.exportJsonBtn?.addEventListener('click', () => this._exportJson());
        this.exportPdfBtn?.addEventListener('click', () => this._exportStatsPdf());
        this.exportUsersPdfBtn?.addEventListener('click', () => this._exportUsersPdf());
        this.exportChatJsonBtn?.addEventListener('click', () => this._exportChatJson());
        this.exportChatPdfBtn?.addEventListener('click', () => this._exportChatPdf());
        this.clearBtn?.addEventListener('click', () => this._confirmClearLogs());
        
        // Help button
        this.helpBtn?.addEventListener('click', () => this._showHelp());
        this.helpClose?.addEventListener('click', () => this._hideHelp());
        
        // User details panel close
        this.closeUserDetailsBtn?.addEventListener('click', () => this._hideUserDetails());
        
        // Close dropdown when clicking outside
        document.addEventListener('click', (e) => {
            if (this.exportDropdown && !this.exportDropdown.contains(e.target)) {
                this.exportDropdown.classList.remove('open');
            }
        });
        
        // Dialog
        this.dialogCancel?.addEventListener('click', () => this._hideDialog());
        this.dialogOverlay?.addEventListener('click', (e) => {
            if (e.target === this.dialogOverlay) this._hideDialog();
        });
        
        this.helpOverlay?.addEventListener('click', (e) => {
            if (e.target === this.helpOverlay) this._hideHelp();
        });
    }

    // ==================== AUTHENTICATION ====================
    _checkAuth() {
        const token = localStorage.getItem(TOKEN_KEY);
        if (token && this._isTokenValid(token)) {
            this.token = token;
            this._showApp();
            this._loadData();
        } else {
            localStorage.removeItem(TOKEN_KEY);
            this._showLogin();
        }
    }

    _isTokenValid(token) {
        try {
            const payload = JSON.parse(atob(token.split('.')[1]));
            return payload.exp * 1000 > Date.now();
        } catch {
            return false;
        }
    }

    async _handleLogin(e) {
        e.preventDefault();
        const password = this.passwordInput?.value?.trim();
        
        if (!password) {
            this._showLoginError('Please enter a password');
            return;
        }
        
        this._setLoginLoading(true);
        
        try {
            const response = await fetch(`${API_BASE}/login`, {
                method: 'POST',
                headers: { 'Content-Type': 'application/json' },
                body: JSON.stringify({ password })
            });
            
            const data = await response.json();
            
            if (data.success && data.token) {
                this.token = data.token;
                localStorage.setItem(TOKEN_KEY, data.token);
                this._showApp();
                this._loadData();
                this._showToast('Login successful', 'success');
            } else {
                this._showLoginError(data.error || 'Invalid password');
                if (data.attemptsLeft !== undefined) {
                    this.loginAttempts.textContent = `${data.attemptsLeft} attempts remaining`;
                }
                if (data.lockoutTime) {
                    this._showLoginError(`Too many attempts. Try again in ${Math.ceil(data.lockoutTime / 60)} minutes`);
                }
            }
        } catch (err) {
            this._showLoginError('Connection error. Please try again.');
        } finally {
            this._setLoginLoading(false);
        }
    }

    _logout() {
        localStorage.removeItem(TOKEN_KEY);
        this.token = null;
        if (this.refreshInterval) clearInterval(this.refreshInterval);
        if (this.lastUpdatedInterval) clearInterval(this.lastUpdatedInterval);
        this._showLogin();
        this._showToast('Logged out successfully', 'success');
    }

    _showLogin() {
        this.loginOverlay.style.display = 'flex';
        this.app.style.display = 'none';
        this.passwordInput.value = '';
        this.loginError.textContent = '';
        this.loginAttempts.textContent = '';
    }

    _showApp() {
        this.loginOverlay.style.display = 'none';
        this.app.style.display = 'flex';
        
        // Initialize breadcrumb
        this._updateBreadcrumb(['Dashboard']);
        
        // Auto-refresh every 5 seconds for real-time updates
        this.refreshInterval = setInterval(() => this._loadData(), 5000);
        // Update "last updated" display every second
        this.lastUpdatedInterval = setInterval(() => this._updateLastUpdatedDisplay(), 1000);
    }

    _showLoginError(msg) {
        this.loginError.textContent = msg;
    }

    _setLoginLoading(loading) {
        const btnText = this.loginBtn?.querySelector('.btn-text');
        const btnLoading = this.loginBtn?.querySelector('.btn-loading');
        if (loading) {
            btnText.style.display = 'none';
            btnLoading.style.display = 'inline-flex';
            this.loginBtn.disabled = true;
        } else {
            btnText.style.display = 'inline';
            btnLoading.style.display = 'none';
            this.loginBtn.disabled = false;
        }
    }

    // ==================== ENHANCED DATA LOADING ====================
    async _loadData() {
        try {
            // Show loading state with context
            this._setLoadingState(true, 'loading');
            
            const [statsRes, usersRes] = await Promise.all([
                this._apiGet('/stats'),
                this._apiGet('/users')
            ]);
            
            if (statsRes.success) {
                this.stats = statsRes.data;
                this._renderStats();
            }
            
            if (usersRes.success) {
                // Smart update: only re-render if data actually changed
                const newUsers = usersRes.data.users || [];
                if (this._hasUsersChanged(newUsers)) {
                    this.users = newUsers;
                    this._renderUsers();
                } else {
                    // Just update timestamps and status
                    this._updateUserTimestamps(newUsers);
                }
            }
            
            // Update last updated time
            this.lastUpdateTime = Date.now();
            this._updateLastUpdatedDisplay();
            
            // Hide loading state
            this._setLoadingState(false);
        } catch (err) {
            console.error('Failed to load data:', err);
            this._setLoadingState(false);
            if (err.message === 'Unauthorized') {
                this._logout();
            } else {
                this._showToast('Failed to load data', 'error');
            }
        }
    }
    
    _hasUsersChanged(newUsers) {
        if (!this.users || this.users.length !== newUsers.length) return true;
        
        // Quick check for significant changes
        for (let i = 0; i < newUsers.length; i++) {
            const oldUser = this.users.find(u => u.ip === newUsers[i].ip);
            const newUser = newUsers[i];
            if (!oldUser || oldUser.chatCount !== newUser.chatCount) {
                return true;
            }
        }
        return false;
    }
    
    _updateUserTimestamps(newUsers) {
        // Update existing user cards with new timestamps without full re-render
        newUsers.forEach(newUser => {
            const userCard = this.userList?.querySelector(`[data-ip="${this.escapeHtml(newUser.ip)}"]`);
            if (userCard) {
                const timeElement = userCard.querySelector('.user-time');
                const statusElement = userCard.querySelector('.user-status');
                
                if (timeElement) {
                    timeElement.textContent = this._formatTimeAgo(newUser.lastActivity);
                }
                
                if (statusElement) {
                    statusElement.classList.toggle('online', newUser.isOnline);
                    statusElement.classList.toggle('status-indicator', newUser.isOnline);
                }
            }
        });
        
        // Update the users array
        this.users = newUsers;
    }
    
    _setLoadingState(loading, context = 'data') {
        const elements = [this.userList, this.modelUsageChart];
        elements.forEach(el => {
            if (el) {
                if (loading) {
                    el.classList.add('loading-pulse');
                    // Add contextual loading message
                    if (context === 'refresh') {
                        el.style.opacity = '0.7';
                    }
                } else {
                    el.classList.remove('loading-pulse');
                    el.style.opacity = '1';
                }
            }
        });
        
        // Update refresh button state with better feedback
        if (this.refreshBtn) {
            if (loading) {
                this.refreshBtn.disabled = true;
                this.refreshBtn.classList.add('spinning', 'loading');
                this.refreshBtn.querySelector('span').textContent = 'Refreshing...';
            } else {
                this.refreshBtn.disabled = false;
                this.refreshBtn.classList.remove('spinning', 'loading');
                this.refreshBtn.querySelector('span').textContent = 'Refresh';
            }
        }
    }
    
    _updateLastUpdatedDisplay() {
        if (!this.lastUpdated || !this.lastUpdateTime) return;
        
        const seconds = Math.floor((Date.now() - this.lastUpdateTime) / 1000);
        const indicator = document.getElementById('autoRefreshIndicator');
        
        if (seconds < 5) {
            this.lastUpdated.textContent = 'Updated just now';
            this.lastUpdated.style.color = 'var(--success)';
            if (indicator) indicator.style.opacity = '1';
        } else if (seconds < 60) {
            this.lastUpdated.textContent = `Updated ${seconds}s ago`;
            this.lastUpdated.style.color = 'var(--text-secondary)';
            if (indicator) indicator.style.opacity = '0.7';
        } else {
            const mins = Math.floor(seconds / 60);
            this.lastUpdated.textContent = `Updated ${mins}m ago`;
            this.lastUpdated.style.color = mins > 5 ? 'var(--warning)' : 'var(--text-tertiary)';
            if (indicator) indicator.style.opacity = mins > 5 ? '0.5' : '0.6';
        }
    }

    async _loadUserChats(userIp) {
        try {
            const res = await this._apiGet(`/users/${encodeURIComponent(userIp)}/chats`);
            if (res.success) {
                this.chats = res.data.chats || [];
                this._renderChats();
            }
        } catch (err) {
            console.error('Failed to load chats:', err);
            this._showToast('Failed to load chats', 'error');
        }
    }

    async _loadChatMessages(chatId) {
        try {
            const res = await this._apiGet(`/chats/${encodeURIComponent(chatId)}/messages`);
            if (res.success) {
                this._currentMessages = res.data.messages || [];
                this._renderMessages(this._currentMessages, res.data.chat);
            }
        } catch (err) {
            console.error('Failed to load messages:', err);
            this._showToast('Failed to load messages', 'error');
        }
    }

    async _apiGet(endpoint) {
        try {
            this._updateConnectionStatus('connecting');
            
            const response = await fetch(`${API_BASE}${endpoint}`, {
                headers: { 'Authorization': `Bearer ${this.token}` }
            });
            
            if (response.status === 401) {
                this._updateConnectionStatus('disconnected');
                throw new Error('Unauthorized');
            }
            
            if (!response.ok) {
                this._updateConnectionStatus('error');
                throw new Error(`HTTP ${response.status}`);
            }
            
            this._updateConnectionStatus('connected');
            return response.json();
        } catch (err) {
            this._updateConnectionStatus('error');
            throw err;
        }
    }

    async _apiPost(endpoint, data) {
        try {
            this._updateConnectionStatus('connecting');
            
            const response = await fetch(`${API_BASE}${endpoint}`, {
                method: 'POST',
                headers: {
                    'Content-Type': 'application/json',
                    'Authorization': `Bearer ${this.token}`
                },
                body: JSON.stringify(data)
            });
            
            if (response.status === 401) {
                this._updateConnectionStatus('disconnected');
                throw new Error('Unauthorized');
            }
            
            if (!response.ok) {
                this._updateConnectionStatus('error');
                throw new Error(`HTTP ${response.status}`);
            }
            
            this._updateConnectionStatus('connected');
            return response.json();
        } catch (err) {
            this._updateConnectionStatus('error');
            throw err;
        }
    }
    
    _updateConnectionStatus(status) {
        if (!this.connectionStatus) return;
        
        // Remove all status classes
        this.connectionStatus.classList.remove('disconnected', 'reconnecting', 'error');
        
        switch (status) {
            case 'connected':
                this.connectionText.textContent = 'Connected';
                break;
            case 'connecting':
            case 'reconnecting':
                this.connectionStatus.classList.add('reconnecting');
                this.connectionText.textContent = 'Connecting...';
                break;
            case 'disconnected':
                this.connectionStatus.classList.add('disconnected');
                this.connectionText.textContent = 'Disconnected';
                break;
            case 'error':
                this.connectionStatus.classList.add('disconnected');
                this.connectionText.textContent = 'Connection Error';
                break;
        }
    }

    // ==================== RENDERING ====================
    _renderStats() {
        const s = this.stats;
        this.totalUsers.textContent = s.totalUsers || 0;
        this.totalChats.textContent = s.totalChats || 0;
        this.todayQueries.textContent = s.todayQueries || 0;
        
        // Render trend indicators
        this._renderTrendIndicator(this.usersTrend, s.totalUsers, s.previousUsers);
        this._renderTrendIndicator(this.chatsTrend, s.totalChats, s.previousChats);
        this._renderTrendIndicator(this.todayTrend, s.todayQueries, s.previousTodayQueries);
        
        if (this.avgResponseTime) {
            this.avgResponseTime.textContent = `${s.avgResponseTime || 0}ms`;
        }
        if (this.totalMessages) {
            this.totalMessages.textContent = s.totalMessages || 0;
        }
        if (this.activeSessions) {
            this.activeSessions.textContent = s.activeSessions || 0;
        }
        
        // New enhanced stats
        if (this.peakHour && s.peakHour !== undefined) {
            const hour = s.peakHour;
            const hourStr = hour === 0 ? '12 AM' : hour < 12 ? `${hour} AM` : hour === 12 ? '12 PM' : `${hour - 12} PM`;
            this.peakHour.textContent = hourStr;
        }
        
        if (this.onlineUsers) {
            this.onlineUsers.textContent = s.activeSessions || 0;
        }
        
        if (this.avgChatsPerUser) {
            this.avgChatsPerUser.textContent = s.avgChatsPerUser || '0';
        }
        
        // Enhanced analytics
        if (this.yesterdayQueries) {
            this.yesterdayQueries.textContent = s.yesterdayQueries || 0;
        }
        if (this.weekQueries) {
            this.weekQueries.textContent = s.weekQueries || 0;
        }
        if (this.monthQueries) {
            this.monthQueries.textContent = s.monthQueries || 0;
        }
        if (this.newUsersToday) {
            this.newUsersToday.textContent = s.newUsersToday || 0;
        }
        if (this.newUsersWeek) {
            this.newUsersWeek.textContent = s.newUsersWeek || 0;
        }
        if (this.avgMessagesPerChat) {
            this.avgMessagesPerChat.textContent = s.avgMessagesPerChat || '0';
        }
        
        // Update summary section
        if (this.summaryTotalUsers) {
            this.summaryTotalUsers.textContent = s.totalUsers || 0;
        }
        if (this.summaryOnline) {
            this.summaryOnline.textContent = s.activeSessions || 0;
        }
        if (this.summaryToday) {
            this.summaryToday.textContent = s.todayQueries || 0;
        }
        
        // Render sparklines
        this._renderSparkline(this.responseTimeSparkline, s.responseTimeHistory);
        this._renderSparkline(this.messagesSparkline, s.messageHistory);
        this._renderActivityIndicator(this.activityIndicator, s.activeSessions || 0);
        
        // Render daily activity chart
        if (this.dailyActivityChart && s.dailyActivity) {
            this._renderDailyActivity(s.dailyActivity);
        }
        
        // Render browser and OS distribution
        if (this.browserDistribution && s.browserStats) {
            this._renderDistribution(this.browserDistribution, s.browserStats, 'browser');
        }
        if (this.osDistribution && s.osStats) {
            this._renderDistribution(this.osDistribution, s.osStats, 'os');
        }
        if (this.deviceDistribution && s.deviceStats) {
            this._renderDistribution(this.deviceDistribution, s.deviceStats, 'device');
        }
        if (this.languageDistribution && s.languageStats) {
            this._renderDistribution(this.languageDistribution, s.languageStats, 'language');
        }
        if (this.refererDistribution && s.refererStats) {
            this._renderDistribution(this.refererDistribution, s.refererStats, 'referer');
        }
        if (this.countryDistribution && s.countryStats) {
            this._renderDistribution(this.countryDistribution, s.countryStats, 'country');
        }
        if (this.screenDistribution && s.screenStats) {
            this._renderDistribution(this.screenDistribution, s.screenStats, 'screen');
        }
        
        // Render new real-time metrics
        if (this.realtimeOnline) {
            this.realtimeOnline.textContent = s.activeSessions || 0;
        }
        if (this.lastHourQueries) {
            this.lastHourQueries.textContent = s.lastHourQueries || 0;
        }
        if (this.returningUsers) {
            this.returningUsers.textContent = s.returningUsers || 0;
        }
        if (this.returningRate) {
            this.returningRate.textContent = (s.returningRate || 0) + '%';
        }
        
        // Render engagement metrics
        if (this.totalPageViews) {
            this.totalPageViews.textContent = this._formatNumber(s.totalPageViews || 0);
        }
        if (this.avgPageViews) {
            this.avgPageViews.textContent = s.avgPageViewsPerUser || 0;
        }
        if (this.avgSessionDurationEl) {
            this.avgSessionDurationEl.textContent = (s.avgSessionDuration || 0) + 'm';
        }
        if (this.totalSessionsEl) {
            this.totalSessionsEl.textContent = this._formatNumber(s.totalSessions || 0);
        }
        if (this.bounceRateEl) {
            this.bounceRateEl.textContent = (s.bounceRate || 0) + '%';
        }
        if (this.newUsersMonthEl) {
            this.newUsersMonthEl.textContent = s.newUsersMonth || 0;
        }
        
        // Render error metrics
        if (this.totalErrorsEl) {
            this.totalErrorsEl.textContent = s.totalErrors || 0;
        }
        if (this.errorRateEl) {
            this.errorRateEl.textContent = (s.errorRate || 0) + '%';
        }
        if (this.recentErrorsEl) {
            this.recentErrorsEl.textContent = s.recentErrors || 0;
        }
        if (this.totalTokensEl) {
            this.totalTokensEl.textContent = this._formatNumber(s.totalTokens || 0);
        }
        
        // Render top users
        if (this.topUsersChart && s.topUsers) {
            this._renderTopUsers(s.topUsers);
        }
        
        // Render hourly usage chart
        if (this.hourlyUsageChart && s.hourlyUsage) {
            this._renderHourlyUsage(s.hourlyUsage, s.peakHour);
        }
        
        // Render model usage chart
        if (this.modelUsageChart && s.modelUsage) {
            this._renderModelUsage(s.modelUsage);
        }
        
        // Render system health
        if (this.systemHealthChart && s.systemHealth) {
            this._renderSystemHealth(s.systemHealth);
        }
        
        // Render performance indicators
        if (this.performanceIndicators && s.systemHealth) {
            this._renderPerformanceIndicators(s.systemHealth);
        }
        
        // Render server info
        if (this.serverInfoChart && s.systemHealth) {
            this._renderServerInfo(s.systemHealth);
        }
        
        // Render user insights
        this._renderUserInsights(s);
        
        // Render weekly heatmap
        if (this.weeklyHeatmap && s.hourlyUsage) {
            this._renderWeeklyHeatmap(s.hourlyUsage);
        }
    }
    
    _renderUserInsights(stats) {
        // Calculate average engagement from users
        if (this.avgEngagement && this.users.length > 0) {
            const totalEngagement = this.users.reduce((sum, u) => sum + (u.engagementScore || 0), 0);
            const avgEng = Math.round(totalEngagement / this.users.length);
            this.avgEngagement.textContent = avgEng + '%';
        }
        
        // Calculate average time on site
        if (this.avgTimeOnSite) {
            const avgTime = stats.avgSessionDuration || 0;
            this.avgTimeOnSite.textContent = avgTime + 'm';
        }
        
        // Calculate mobile percentage
        if (this.mobilePercent && stats.deviceStats) {
            const total = Object.values(stats.deviceStats).reduce((a, b) => a + b, 0) || 1;
            const mobile = (stats.deviceStats['Mobile'] || 0) + (stats.deviceStats['Tablet'] || 0);
            const mobilePerc = Math.round((mobile / total) * 100);
            this.mobilePercent.textContent = mobilePerc + '%';
        }
        
        // Calculate average sessions per user
        if (this.avgSessionsPerUser && stats.totalUsers > 0) {
            const avgSessions = (stats.totalSessions / stats.totalUsers).toFixed(1);
            this.avgSessionsPerUser.textContent = avgSessions;
        }
    }
    
    _renderWeeklyHeatmap(hourlyUsage) {
        if (!this.weeklyHeatmap) return;
        
        // Generate mock weekly data based on hourly usage pattern
        const days = ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun'];
        const maxVal = Math.max(...(hourlyUsage || []), 1);
        
        let html = '<div class="heatmap-grid">';
        
        // Generate rows for each day
        days.forEach((day, dayIndex) => {
            html += `<div class="heatmap-row">`;
            html += `<div class="heatmap-day-label">${day}</div>`;
            
            // Generate cells for each hour
            for (let hour = 0; hour < 24; hour++) {
                // Use hourly data with some variation per day
                const baseVal = hourlyUsage ? (hourlyUsage[hour] || 0) : 0;
                const variation = Math.random() * 0.4 + 0.8; // 0.8 to 1.2
                const val = Math.round(baseVal * variation);
                const level = Math.min(Math.floor((val / maxVal) * 5), 5);
                
                html += `<div class="heatmap-cell level-${level}" title="${day} ${hour}:00 - ${val} activities"></div>`;
            }
            
            html += `</div>`;
        });
        
        html += '</div>';
        
        // Add hour labels
        html += '<div class="heatmap-hour-labels">';
        html += '<div></div>'; // Empty cell for day label column
        for (let hour = 0; hour < 24; hour++) {
            if (hour % 3 === 0) {
                html += `<div class="heatmap-hour-label">${hour}</div>`;
            } else {
                html += '<div></div>';
            }
        }
        html += '</div>';
        
        // Add legend
        html += `
            <div class="heatmap-legend">
                <span>Less</span>
                <div class="heatmap-legend-cell level-0"></div>
                <div class="heatmap-legend-cell level-1"></div>
                <div class="heatmap-legend-cell level-2"></div>
                <div class="heatmap-legend-cell level-3"></div>
                <div class="heatmap-legend-cell level-4"></div>
                <div class="heatmap-legend-cell level-5"></div>
                <span>More</span>
            </div>
        `;
        
        this.weeklyHeatmap.innerHTML = html;
    }
    
    _renderDailyActivity(dailyData) {
        if (!this.dailyActivityChart || !dailyData || !Array.isArray(dailyData)) return;
        
        const maxValue = Math.max(...dailyData.map(d => d.count), 1);
        
        let html = '<div class="daily-bars">';
        dailyData.forEach(day => {
            const height = Math.max((day.count / maxValue) * 100, 5);
            html += `
                <div class="daily-bar-wrapper">
                    <div class="daily-bar" style="height: ${height}%">
                        <span class="daily-bar-value">${day.count}</span>
                    </div>
                    <span class="daily-bar-label">${day.date.split(',')[0]}</span>
                </div>
            `;
        });
        html += '</div>';
        
        this.dailyActivityChart.innerHTML = html;
    }
    
    _renderDistribution(element, data, type) {
        if (!element || !data) return;
        
        const total = Object.values(data).reduce((a, b) => a + b, 0) || 1;
        const sorted = Object.entries(data).sort(([,a], [,b]) => b - a); // Show all items
        
        const icons = {
            browser: {
                'Chrome': '🌐', 'Firefox': '🦊', 'Safari': '🧭', 'Edge': '📘', 
                'Opera': '🔴', 'Brave': '🦁', 'Vivaldi': '🎨', 'Unknown': '❓'
            },
            os: {
                'Windows': '🪟', 'macOS': '🍎', 'Linux': '🐧', 'Android': '🤖', 
                'iOS': '📱', 'Chrome OS': '💻', 'Ubuntu': '🟠', 'Unknown': '❓'
            },
            device: {
                'Desktop': '🖥️', 'Mobile': '📱', 'Tablet': '📲', 'Unknown': '❓'
            },
            language: {
                'en': '🇺🇸', 'es': '🇪🇸', 'fr': '🇫🇷', 'de': '🇩🇪', 'zh': '🇨🇳',
                'ja': '🇯🇵', 'ko': '🇰🇷', 'pt': '🇧🇷', 'ru': '🇷🇺', 'ar': '🇸🇦',
                'hi': '🇮🇳', 'it': '🇮🇹', 'Unknown': '🌍'
            }
        };
        
        const colors = ['#667eea', '#764ba2', '#3eb489', '#f59e0b', '#ef4444', '#06b6d4', '#8b5cf6', '#ec4899'];
        
        if (sorted.length === 0) {
            element.innerHTML = '<div class="no-data" style="padding: 12px; text-align: center; color: var(--text-tertiary); font-size: 12px;">No data available</div>';
            return;
        }
        
        let html = '';
        sorted.forEach(([name, count], index) => {
            const percent = Math.round((count / total) * 100);
            const icon = icons[type]?.[name] || icons[type]?.['Unknown'] || '📊';
            const color = colors[index % colors.length];
            
            html += `
                <div class="distribution-item">
                    <span class="distribution-icon">${icon}</span>
                    <span class="distribution-name" title="${this.escapeHtml(name)}">${this.escapeHtml(name)}</span>
                    <div class="distribution-bar">
                        <div class="distribution-fill" style="width: ${percent}%; background: ${color};"></div>
                    </div>
                    <span class="distribution-count">${count}</span>
                    <span class="distribution-percent">${percent}%</span>
                </div>
            `;
        });
        
        element.innerHTML = html;
    }
    
    _renderTopUsers(topUsers) {
        if (!this.topUsersChart || !topUsers || topUsers.length === 0) {
            if (this.topUsersChart) {
                this.topUsersChart.innerHTML = '<div class="no-data" style="padding: 20px; text-align: center; color: var(--text-tertiary);">No user data yet</div>';
            }
            return;
        }
        
        let html = '';
        topUsers.forEach((user, index) => {
            const rankClass = index === 0 ? 'gold' : index === 1 ? 'silver' : index === 2 ? 'bronze' : '';
            html += `
                <div class="top-user-item">
                    <div class="top-user-rank ${rankClass}">${index + 1}</div>
                    <div class="top-user-info">
                        <div class="top-user-ip">${this.escapeHtml(user.ip)}</div>
                        <div class="top-user-stats">
                            <div class="top-user-stat">💬 <span>${user.chats}</span> chats</div>
                            <div class="top-user-stat">📝 <span>${user.messages}</span> msgs</div>
                            <div class="top-user-stat">🔄 <span>${user.sessions}</span> sessions</div>
                        </div>
                    </div>
                </div>
            `;
        });
        
        this.topUsersChart.innerHTML = html;
    }
    
    _formatNumber(num) {
        if (num >= 1000000) {
            return (num / 1000000).toFixed(1) + 'M';
        } else if (num >= 1000) {
            return (num / 1000).toFixed(1) + 'K';
        }
        return num.toString();
    }
    
    _renderTrendIndicator(element, current, previous) {
        if (!element) return;
        
        const currentVal = current || 0;
        const previousVal = previous || 0;
        
        if (previousVal === 0) {
            element.innerHTML = '<div class="trend-arrow neutral"></div><span>--</span>';
            element.className = 'stat-trend neutral';
            return;
        }
        
        const change = currentVal - previousVal;
        const percentChange = Math.round((change / previousVal) * 100);
        
        if (change > 0) {
            element.innerHTML = `<div class="trend-arrow up"></div><span>+${percentChange}%</span>`;
            element.className = 'stat-trend up';
        } else if (change < 0) {
            element.innerHTML = `<div class="trend-arrow down"></div><span>${percentChange}%</span>`;
            element.className = 'stat-trend down';
        } else {
            element.innerHTML = '<div class="trend-arrow neutral"></div><span>0%</span>';
            element.className = 'stat-trend neutral';
        }
    }
    
    _renderSparkline(element, data) {
        if (!element) return;
        
        // Generate mock data if none provided (for demo purposes)
        if (!data || !Array.isArray(data) || data.length === 0) {
            data = Array.from({length: 20}, () => Math.floor(Math.random() * 100));
        }
        
        const maxValue = Math.max(...data, 1);
        const bars = data.slice(-20).map(value => {
            const height = Math.max((value / maxValue) * 16, 2);
            return `<div class="sparkline-bar" style="--height: ${height}px; height: ${height}px;"></div>`;
        }).join('');
        
        element.innerHTML = bars;
    }
    
    _renderActivityIndicator(element, sessionCount) {
        if (!element) return;
        
        const maxDots = 8;
        const activeDots = Math.min(Math.max(sessionCount || 0, 0), maxDots);
        
        let html = '';
        for (let i = 0; i < maxDots; i++) {
            const isActive = i < activeDots;
            html += `<div class="activity-dot ${isActive ? 'active' : ''}"></div>`;
        }
        
        element.innerHTML = html;
    }
    
    _renderPerformanceIndicators(health) {
        if (!this.performanceIndicators) return;
        
        if (!health || !health.memoryUsage) {
            this.performanceIndicators.innerHTML = `
                <div class="perf-indicator">
                    <div class="perf-dot loading"></div>
                    <span>Loading...</span>
                </div>
            `;
            return;
        }
        
        const memoryPercent = Math.round((health.memoryUsage.heapUsed / health.memoryUsage.heapTotal) * 100);
        const uptimeHours = Math.floor((health.uptime || 0) / 3600);
        
        let memoryStatus = 'excellent';
        if (memoryPercent > 80) memoryStatus = 'poor';
        else if (memoryPercent > 60) memoryStatus = 'fair';
        else if (memoryPercent > 40) memoryStatus = 'good';
        
        let uptimeStatus = 'excellent';
        if (uptimeHours < 1) uptimeStatus = 'poor';
        else if (uptimeHours < 24) uptimeStatus = 'fair';
        else if (uptimeHours < 168) uptimeStatus = 'good';
        
        const html = `
            <div class="perf-indicator">
                <div class="perf-dot ${memoryStatus}"></div>
                <span>Memory ${memoryPercent}%</span>
            </div>
            <div class="perf-indicator">
                <div class="perf-dot ${uptimeStatus}"></div>
                <span>Uptime ${uptimeHours}h</span>
            </div>
        `;
        
        this.performanceIndicators.innerHTML = html;
    }
    
    _renderServerInfo(health) {
        if (!this.serverInfoChart) return;
        
        if (!health) {
            this.serverInfoChart.innerHTML = '<div class="no-data">No server info available</div>';
            return;
        }
        
        const uptimeSeconds = health.uptime || 0;
        const uptimeDays = Math.floor(uptimeSeconds / 86400);
        const uptimeHours = Math.floor((uptimeSeconds % 86400) / 3600);
        const uptimeMinutes = Math.floor((uptimeSeconds % 3600) / 60);
        
        let uptimeStr = '';
        if (uptimeDays > 0) uptimeStr += `${uptimeDays}d `;
        if (uptimeHours > 0 || uptimeDays > 0) uptimeStr += `${uptimeHours}h `;
        uptimeStr += `${uptimeMinutes}m`;
        
        const memoryMB = health.memoryUsage ? Math.round(health.memoryUsage.heapUsed / 1024 / 1024) : 0;
        const memoryTotalMB = health.memoryUsage ? Math.round(health.memoryUsage.heapTotal / 1024 / 1024) : 0;
        const rssMB = health.memoryUsage ? Math.round(health.memoryUsage.rss / 1024 / 1024) : 0;
        const externalMB = health.memoryUsage ? Math.round((health.memoryUsage.external || 0) / 1024 / 1024) : 0;
        
        const html = `
            <div class="server-info-item">
                <span class="server-info-label">Node.js Version</span>
                <span class="server-info-value">${this.escapeHtml(health.nodeVersion || 'Unknown')}</span>
            </div>
            <div class="server-info-item">
                <span class="server-info-label">Server Uptime</span>
                <span class="server-info-value">${uptimeStr}</span>
            </div>
            <div class="server-info-item">
                <span class="server-info-label">Heap Memory</span>
                <span class="server-info-value">${memoryMB}MB / ${memoryTotalMB}MB</span>
            </div>
            <div class="server-info-item">
                <span class="server-info-label">RSS Memory</span>
                <span class="server-info-value">${rssMB}MB</span>
            </div>
            <div class="server-info-item">
                <span class="server-info-label">External Memory</span>
                <span class="server-info-value">${externalMB}MB</span>
            </div>
            <div class="server-info-item">
                <span class="server-info-label">Platform</span>
                <span class="server-info-value">${this.escapeHtml(health.platform || process?.platform || 'Unknown')}</span>
            </div>
        `;
        
        this.serverInfoChart.innerHTML = html;
    }
    
    _renderHourlyUsage(hourlyData, peakHour) {
        if (!this.hourlyUsageChart) return;
        
        if (!hourlyData || !Array.isArray(hourlyData) || hourlyData.length === 0) {
            // Generate placeholder data
            hourlyData = new Array(24).fill(0);
        }
        
        const maxValue = Math.max(...hourlyData, 1);
        
        let barsHtml = '';
        for (let i = 0; i < 24; i++) {
            const value = hourlyData[i] || 0;
            const height = Math.max((value / maxValue) * 100, 2);
            const isPeak = i === peakHour;
            barsHtml += `<div class="hourly-bar ${isPeak ? 'peak' : ''}" style="height: ${height}%" title="${i}:00 - ${value} requests"></div>`;
        }
        
        const html = `
            <div class="hourly-bars">${barsHtml}</div>
            <div class="hourly-labels">
                <span class="hourly-label">12AM</span>
                <span class="hourly-label">6AM</span>
                <span class="hourly-label">12PM</span>
                <span class="hourly-label">6PM</span>
                <span class="hourly-label">11PM</span>
            </div>
        `;
        
        this.hourlyUsageChart.innerHTML = html;
    }

    _renderModelUsage(usage) {
        const total = Object.values(usage).reduce((a, b) => a + b, 0) || 1;
        
        // Sort models by usage count (descending)
        const sortedUsage = Object.entries(usage).sort(([,a], [,b]) => b - a);
        
        let html = '';
        
        for (const [model, count] of sortedUsage) {
            const percent = Math.round((count / total) * 100);
            const barColor = this._getModelColor(model);
            
            html += `
                <div class="usage-bar fade-in">
                    <span class="usage-bar-label" title="${this.escapeHtml(model)}">${this.escapeHtml(model)}</span>
                    <div class="usage-bar-track">
                        <div class="usage-bar-fill" style="width: ${percent}%; background: ${barColor}"></div>
                    </div>
                    <span class="usage-bar-value">${count} (${percent}%)</span>
                </div>
            `;
        }
        
        this.modelUsageChart.innerHTML = html || '<div class="no-data">No usage data</div>';
    }
    
    _getModelColor(model) {
        // Assign consistent colors to different models
        const colors = [
            'linear-gradient(135deg, #667eea 0%, #764ba2 100%)',
            'linear-gradient(135deg, #f093fb 0%, #f5576c 100%)',
            'linear-gradient(135deg, #4facfe 0%, #00f2fe 100%)',
            'linear-gradient(135deg, #43e97b 0%, #38f9d7 100%)',
            'linear-gradient(135deg, #fa709a 0%, #fee140 100%)'
        ];
        
        // Simple hash function to assign consistent colors
        let hash = 0;
        for (let i = 0; i < model.length; i++) {
            hash = ((hash << 5) - hash + model.charCodeAt(i)) & 0xffffffff;
        }
        return colors[Math.abs(hash) % colors.length];
    }
    
    _renderSystemHealth(health) {
        if (!health) {
            this.systemHealthChart.innerHTML = '<div class="no-data">No health data</div>';
            return;
        }
        
        const memoryMB = Math.round(health.memoryUsage.heapUsed / 1024 / 1024);
        const memoryTotalMB = Math.round(health.memoryUsage.heapTotal / 1024 / 1024);
        const memoryPercent = Math.round((health.memoryUsage.heapUsed / health.memoryUsage.heapTotal) * 100);
        const uptimeHours = Math.floor(health.uptime / 3600);
        const uptimeDays = Math.floor(uptimeHours / 24);
        
        let uptimeText = '';
        if (uptimeDays > 0) {
            uptimeText = `${uptimeDays}d ${uptimeHours % 24}h`;
        } else {
            uptimeText = `${uptimeHours}h`;
        }
        
        const healthColor = memoryPercent > 80 ? '#ef4444' : memoryPercent > 60 ? '#f59e0b' : '#10b981';
        
        const html = `
            <div class="health-metrics fade-in">
                <div class="health-metric">
                    <div class="health-metric-label">Memory Usage</div>
                    <div class="health-metric-value">${memoryMB}MB / ${memoryTotalMB}MB</div>
                    <div class="health-progress">
                        <div class="health-progress-fill" style="width: ${memoryPercent}%; background: ${healthColor}"></div>
                    </div>
                    <div class="health-metric-percent">${memoryPercent}%</div>
                </div>
                <div class="health-metric">
                    <div class="health-metric-label">Uptime</div>
                    <div class="health-metric-value">${uptimeText}</div>
                </div>
                <div class="health-metric">
                    <div class="health-metric-label">Node.js Version</div>
                    <div class="health-metric-value">${health.nodeVersion}</div>
                </div>
            </div>
        `;
        
        this.systemHealthChart.innerHTML = html;
    }

    _renderUsers() {
        if (!this.users.length) {
            this.userList.innerHTML = `
                <div class="no-data enhanced-empty-state">
                    <svg width="64" height="64" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.5">
                        <path d="M17 21v-2a4 4 0 00-4-4H5a4 4 0 00-4 4v2"/>
                        <circle cx="9" cy="7" r="4"/>
                        <path d="M23 21v-2a4 4 0 00-3-3.87"/>
                        <path d="M16 3.13a4 4 0 010 7.75"/>
                    </svg>
                    <h3>No Users Yet</h3>
                    <p>Users will appear here when they start chatting with Rox AI</p>
                    <button class="btn btn-secondary btn-sm" onclick="window.open('/', '_blank')">
                        <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
                            <path d="M18 13v6a2 2 0 01-2 2H5a2 2 0 01-2-2V8a2 2 0 012-2h6"/>
                            <polyline points="15 3 21 3 21 9"/>
                            <line x1="10" y1="14" x2="21" y2="3"/>
                        </svg>
                        Open Chat Interface
                    </button>
                </div>
            `;
            return;
        }
        
        // Sort users by activity (online first, then by last activity)
        const sortedUsers = [...this.users].sort((a, b) => {
            if (a.isOnline && !b.isOnline) return -1;
            if (!a.isOnline && b.isOnline) return 1;
            return (b.lastActivity || 0) - (a.lastActivity || 0);
        });
        
        // Virtual scrolling for large lists (>100 users)
        if (sortedUsers.length > 100) {
            this._renderUsersVirtual(sortedUsers);
            return;
        }
        
        let html = '';
        for (const user of sortedUsers) {
            html += this._renderUserCard(user);
        }
        
        this.userList.innerHTML = html;
        this._attachUserEventListeners();
    }
    
    _renderUserCard(user) {
        const isActive = this.currentUser === user.ip;
        const isOnline = user.isOnline ? 'online' : '';
        const timeAgo = this._formatTimeAgo(user.lastActivity);
        const firstSeenDate = user.firstSeen ? new Date(user.firstSeen).toLocaleDateString() : 'Unknown';
        const engagementScore = user.engagementScore || 0;
        const engagementClass = engagementScore >= 70 ? 'high' : engagementScore >= 40 ? 'medium' : 'low';
        
        // User type badge
        const userType = user.userType || 'New';
        const userTypeClass = userType === 'Power User' ? 'power' : userType === 'Returning' ? 'returning' : userType === 'Dormant' ? 'dormant' : 'new';
        
        // Bounce status
        const bounceStatus = user.bounceStatus || ((user.pageViews || 1) === 1 ? 'Bounced' : 'Engaged');
        const bounceClass = bounceStatus === 'Bounced' ? 'bounced' : 'engaged';
        
        return `
            <div class="user-card ${isActive ? 'active' : ''} fade-in" data-ip="${this.escapeHtml(user.ip)}" tabindex="0" role="button" aria-label="Select user ${user.ip}">
                <div class="user-card-header">
                    <span class="user-status ${isOnline} ${isOnline ? 'status-indicator' : ''}"></span>
                    <span class="user-ip" title="Full IP Address: ${this.escapeHtml(user.ip)}">${this.escapeHtml(user.ip)}</span>
                    <span class="user-type-badge ${userTypeClass}">${userType}</span>
                    <span class="user-time">${timeAgo}</span>
                </div>
                <div class="user-meta">
                    <span class="user-chat-count">${user.chatCount || 0} chats</span>
                    <span class="user-badge messages">${user.totalMessages || 0} msgs</span>
                    <span class="user-badge visits">👁 ${user.visits || 1}</span>
                    ${user.avgResponseTime ? `<span class="user-badge response-time" title="Avg Response Time">⚡ ${user.avgResponseTime}ms</span>` : ''}
                    <span class="user-badge bounce ${bounceClass}" title="Bounce Status">${bounceStatus === 'Bounced' ? '🚪' : '✅'} ${bounceStatus}</span>
                </div>
                <div class="user-device-info">
                    ${user.device?.browser ? `<span class="user-badge browser" title="${user.userAgentRaw ? this.escapeHtml(user.userAgentRaw) : 'Browser: ' + this.escapeHtml(user.device.fullBrowser || user.device.browser)}">${this.escapeHtml(user.device.fullBrowser || user.device.browser)}</span>` : ''}
                    ${user.device?.os ? `<span class="user-badge os" title="Operating System">${this.escapeHtml(user.device.fullOs || user.device.os)}</span>` : ''}
                    ${user.device?.device ? `<span class="user-badge device" title="Device Type">${this.escapeHtml(user.device.device)}</span>` : ''}
                </div>
                <div class="user-card-extra">
                    ${user.country ? `<span class="user-extra-badge country" title="Country">🌍 ${this.escapeHtml(user.country)}</span>` : ''}
                    ${user.city ? `<span class="user-extra-badge city" title="City">📍 ${this.escapeHtml(user.city)}</span>` : ''}
                    ${user.screenResolution ? `<span class="user-extra-badge screen" title="Screen Resolution">📐 ${this.escapeHtml(user.screenResolution)}</span>` : ''}
                    ${user.totalTokensUsed ? `<span class="user-extra-badge tokens" title="Tokens Used">🪙 ${this._formatNumber(user.totalTokensUsed)}</span>` : ''}
                    ${user.favoriteModel ? `<span class="user-extra-badge model" title="Favorite Model">⭐ ${this.escapeHtml(user.favoriteModel)}</span>` : ''}
                    ${user.errorCount > 0 ? `<span class="user-extra-badge error" title="Errors">❌ ${user.errorCount}</span>` : ''}
                    ${user.colorScheme ? `<span class="user-extra-badge theme" title="Color Scheme">${user.colorScheme === 'dark' ? '🌙' : '☀️'} ${this.escapeHtml(user.colorScheme)}</span>` : ''}
                    ${user.doNotTrack ? `<span class="user-extra-badge dnt" title="Do Not Track">🛡️ DNT</span>` : ''}
                </div>
                <div class="user-details">
                    <span class="user-detail-item" title="First seen">🆕 ${firstSeenDate}</span>
                    <span class="user-detail-item" title="Sessions">🔄 ${user.sessionCount || 1}</span>
                    ${user.avgSessionDuration ? `<span class="user-detail-item" title="Avg Session Duration">⏱️ ${user.avgSessionDuration}m</span>` : ''}
                    ${user.totalSessionTime ? `<span class="user-detail-item" title="Total Time">⏳ ${user.totalSessionTime}m</span>` : ''}
                    ${user.language && user.language !== 'Unknown' ? `<span class="user-detail-item" title="Language">🗣️ ${this.escapeHtml(user.language)}</span>` : ''}
                    ${user.peakActivityHour !== null ? `<span class="user-detail-item" title="Peak Activity Hour">🕐 ${user.peakActivityHour}:00</span>` : ''}
                    ${user.pageViews ? `<span class="user-detail-item" title="Page Views">📄 ${user.pageViews} views</span>` : ''}
                    ${user.requestCount ? `<span class="user-detail-item" title="Total Requests">📊 ${user.requestCount} reqs</span>` : ''}
                    <span class="user-detail-item ${isOnline ? 'online-status' : 'offline-status'}">${isOnline ? '🟢 Online' : '⚫ Offline'}</span>
                </div>
                ${user.referer && user.referer !== 'Direct' ? `
                <div class="user-referer">
                    <span class="referer-label">Source:</span>
                    <span class="referer-value">${this.escapeHtml(user.referer)}</span>
                </div>
                ` : ''}
                ${user.lastChatTitle ? `
                <div class="user-referer">
                    <span class="referer-label">Last Chat:</span>
                    <span class="referer-value" title="${this.escapeHtml(user.lastChatTitle)}">${this.escapeHtml(user.lastChatTitle.length > 40 ? user.lastChatTitle.substring(0, 40) + '...' : user.lastChatTitle)}</span>
                </div>
                ` : ''}
                ${user.platform ? `
                <div class="user-referer">
                    <span class="referer-label">Platform:</span>
                    <span class="referer-value">${this.escapeHtml(user.platform)}</span>
                </div>
                ` : ''}
                ${user.connectionType ? `
                <div class="user-referer">
                    <span class="referer-label">Connection:</span>
                    <span class="referer-value">${this.escapeHtml(user.connectionType)}</span>
                </div>
                ` : ''}
                <div class="user-engagement">
                    <div class="engagement-bar">
                        <div class="engagement-fill ${engagementClass}" style="width: ${engagementScore}%"></div>
                    </div>
                    <span class="engagement-label">Engagement: ${engagementScore}%</span>
                </div>
                ${user.activityByHour && user.activityByHour.some(v => v > 0) ? `
                <div class="user-activity-mini">
                    <span class="activity-mini-label">Activity Pattern:</span>
                    <div class="activity-mini-chart">
                        ${this._renderMiniActivityChart(user.activityByHour)}
                    </div>
                </div>
                ` : ''}
            </div>
        `;
    }
    
    _renderMiniActivityChart(activityByHour) {
        if (!activityByHour || !Array.isArray(activityByHour)) return '';
        const max = Math.max(...activityByHour, 1);
        return activityByHour.map((val, hour) => {
            const height = Math.max((val / max) * 100, 5);
            const isPeak = val === max && val > 0;
            return `<div class="mini-bar ${isPeak ? 'peak' : ''}" style="height: ${height}%" title="${hour}:00 - ${val} actions"></div>`;
        }).join('');
    }
    
    _renderUsersVirtual(users) {
        // Simple virtual scrolling implementation
        const ITEM_HEIGHT = 76; // Approximate height of user card
        const VISIBLE_ITEMS = Math.ceil(this.userList.clientHeight / ITEM_HEIGHT) + 5; // Buffer
        
        let startIndex = 0;
        const endIndex = Math.min(startIndex + VISIBLE_ITEMS, users.length);
        
        let html = '';
        for (let i = startIndex; i < endIndex; i++) {
            html += this._renderUserCard(users[i]);
        }
        
        // Add placeholder for remaining items
        if (endIndex < users.length) {
            const remainingHeight = (users.length - endIndex) * ITEM_HEIGHT;
            html += `<div style="height: ${remainingHeight}px; display: flex; align-items: center; justify-content: center; color: var(--text-tertiary); font-size: 12px;">+${users.length - endIndex} more users</div>`;
        }
        
        this.userList.innerHTML = html;
        this._attachUserEventListeners();
    }
    
    _attachUserEventListeners() {
        // Add click and keyboard handlers
        this.userList.querySelectorAll('.user-card').forEach(card => {
            card.addEventListener('click', () => this._selectUser(card.dataset.ip));
            card.addEventListener('keydown', (e) => {
                if (e.key === 'Enter' || e.key === ' ') {
                    e.preventDefault();
                    this._selectUser(card.dataset.ip);
                }
            });
        });
    }

    _renderChats() {
        if (!this.chats.length) {
            this.chatsList.innerHTML = `
                <div class="empty-state">
                    <svg width="48" height="48" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.5">
                        <path d="M21 15a2 2 0 01-2 2H7l-4 4V5a2 2 0 012-2h14a2 2 0 012 2z"/>
                    </svg>
                    <p>No chats found for this user</p>
                </div>
            `;
            return;
        }
        
        // Sort chats by last message time (most recent first)
        const sortedChats = [...this.chats].sort((a, b) => (b.lastMessage || 0) - (a.lastMessage || 0));
        
        let html = '';
        for (const chat of sortedChats) {
            const isActive = this.currentChat === chat.id;
            const timeAgo = this._formatTimeAgo(chat.lastMessage);
            const title = chat.title || 'Untitled Chat';
            
            html += `
                <div class="chat-card ${isActive ? 'active' : ''} fade-in" data-id="${this.escapeHtml(chat.id)}" tabindex="0" role="button" aria-label="Select chat ${title}">
                    <div class="chat-card-title">${this.escapeHtml(title)}</div>
                    <div class="chat-card-meta">
                        <span class="chat-card-status ${chat.isActive ? 'active status-indicator' : ''}"></span>
                        <span>${chat.messageCount || 0} messages</span>
                        <span>·</span>
                        <span>${timeAgo}</span>
                    </div>
                </div>
            `;
        }
        
        this.chatsList.innerHTML = html;
        
        // Add click and keyboard handlers
        this.chatsList.querySelectorAll('.chat-card').forEach(card => {
            card.addEventListener('click', () => this._selectChat(card.dataset.id));
            card.addEventListener('keydown', (e) => {
                if (e.key === 'Enter' || e.key === ' ') {
                    e.preventDefault();
                    this._selectChat(card.dataset.id);
                }
            });
        });
    }

    _renderMessages(messages, chatInfo) {
        if (!messages.length) {
            this.messagesArea.innerHTML = `
                <div class="empty-state">
                    <svg width="64" height="64" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.5">
                        <path d="M21 15a2 2 0 01-2 2H7l-4 4V5a2 2 0 012-2h14a2 2 0 012 2z"/>
                    </svg>
                    <p>No messages in this chat</p>
                </div>
            `;
            return;
        }
        
        // Show chat header
        this.chatHeader.style.display = 'flex';
        this.chatTitle.textContent = chatInfo?.title || 'Chat';
        this.chatMeta.textContent = `Started ${this._formatDate(chatInfo?.createdAt)} · ${messages.length} messages`;
        
        let html = '';
        for (const msg of messages) {
            html += this._renderMessage(msg);
        }
        
        this.messagesArea.innerHTML = html;
        this._initCodeCopyButtons();
        this.messagesArea.scrollTop = this.messagesArea.scrollHeight;
    }

    _renderMessage(msg) {
        const isUser = msg.role === 'user';
        const avatar = isUser ? 'U' : 'R';
        const roleName = isUser ? 'User' : 'Rox';
        const time = this._formatTime(msg.timestamp);
        
        // Attachments
        let attachmentsHtml = '';
        if (msg.attachments?.length) {
            attachmentsHtml = '<div class="message-attachments">';
            for (const att of msg.attachments) {
                attachmentsHtml += `
                    <div class="attachment-chip">
                        <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
                            <path d="M14 2H6a2 2 0 00-2 2v16a2 2 0 002 2h12a2 2 0 002-2V8z"/>
                            <polyline points="14 2 14 8 20 8"/>
                        </svg>
                        ${this.escapeHtml(att.name)}
                    </div>
                `;
            }
            attachmentsHtml += '</div>';
        }
        
        // Model badge for assistant
        let modelBadge = '';
        let internetBadge = '';
        if (!isUser) {
            if (msg.model) {
                modelBadge = `<span class="model-badge">${this.escapeHtml(msg.model)}</span>`;
            }
            if (msg.usedInternet) {
                internetBadge = `<span class="internet-badge">🌐 ${this.escapeHtml(msg.internetSource || 'Web')}</span>`;
            }
        }
        
        // Duration for assistant
        let durationHtml = '';
        if (!isUser && msg.duration) {
            durationHtml = `<span class="message-time">${(msg.duration / 1000).toFixed(1)}s</span>`;
        }
        
        return `
            <div class="message ${isUser ? 'user' : 'assistant'} fade-in">
                <div class="message-avatar">${avatar}</div>
                <div class="message-wrapper">
                    <div class="message-header">
                        <span class="message-role">${roleName}</span>
                        ${modelBadge}
                        ${internetBadge}
                        <span class="message-time">${time}</span>
                        ${durationHtml}
                    </div>
                    ${attachmentsHtml}
                    <div class="message-content">${this._formatContent(msg.content)}</div>
                </div>
            </div>
        `;
    }

    // ==================== CONTENT FORMATTING (EXACT MATCH WITH USER SIDE) ====================
    _formatContent(content) {
        if (!content || typeof content !== 'string') return '';
        
        let formatted = content;
        
        // Remove internet search indicator lines
        formatted = formatted.replace(/^🌐\s*Searching for.*?\.\.\.?\s*$/gm, '');
        formatted = formatted.replace(/^🌐\s*LIVE INTERNET SEARCH RESULTS:?\s*$/gm, '');
        formatted = formatted.replace(/^\s*\n+/g, '').replace(/\n{3,}/g, '\n\n');
        
        // ==================== COMPREHENSIVE NUMBER-TEXT SPACING FIX ====================
        // This fixes ALL cases where numbers are attached to text without proper spacing
        
        // STEP 1: Fix numbered list items at start of lines
        // Handle "1AI" -> "1. AI" (number + uppercase letter)
        formatted = formatted.replace(/^(\d+)([A-Z][a-zA-Z])/gm, '$1. $2');
        // Handle "1**text**" -> "1. **text**" (number + bold markdown)
        formatted = formatted.replace(/^(\d+)(\*\*[^*]+\*\*)/gm, '$1. $2');
        // Handle "1text" -> "1. text" (number + any letter at line start)
        formatted = formatted.replace(/^(\d+)([a-zA-Z])/gm, '$1. $2');
        // Handle "1.text" -> "1. text" (dot but no space)
        formatted = formatted.replace(/^(\d+)\.([^\s\d])/gm, '$1. $2');
        // Handle "1)" -> "1. " (parenthesis style to dot style)
        formatted = formatted.replace(/^(\d+)\)\s*/gm, '$1. ');
        // Handle "1-" -> "1. " (dash style to dot style)
        formatted = formatted.replace(/^(\d+)-\s*/gm, '$1. ');
        
        // STEP 2: Fix numbers attached to words ANYWHERE in text (not just line start)
        formatted = formatted.replace(/(\s)(\d+)([A-Z][a-zA-Z])/g, '$1$2. $3');
        formatted = formatted.replace(/(\s)(\d+)([a-z])/g, '$1$2. $3');
        
        // STEP 3: Fix specific patterns like "Word1Word" -> "Word 1. Word"
        formatted = formatted.replace(/([a-zA-Z])(\d+)([A-Z][a-zA-Z])/g, '$1\n$2. $3');
        formatted = formatted.replace(/([a-z])(\d+)([a-z])/g, '$1 $2. $3');
        
        // STEP 4: Fix bullet points without space
        formatted = formatted.replace(/^-([A-Za-z])/gm, '- $1');
        formatted = formatted.replace(/^\*([A-Za-z])/gm, '* $1');
        formatted = formatted.replace(/^•([A-Za-z])/gm, '• $1');
        
        // STEP 5: Fix "For Word" type headers followed by numbered lists
        formatted = formatted.replace(/\n(\d+)([A-Z])/g, '\n$1. $2');
        formatted = formatted.replace(/\n(\d+)([a-z])/g, '\n$1. $2');
        // STEP 6: Fix numbers inside bold markdown (e.g., **1Star** -> **1. Star**)
        formatted = formatted.replace(/\*\*(\d+)([A-Z][a-zA-Z])/g, '**$1. $2');
        formatted = formatted.replace(/\*\*(\d+)([a-z])/g, '**$1. $2');
        
        // Store math blocks temporarily
        const mathBlocks = [];
        const inlineMath = [];
        
        // Protect display math blocks: $$ ... $$ or \[ ... \]
        formatted = formatted.replace(/\$\$([\s\S]*?)\$\$/g, (_, math) => {
            const placeholder = `__MATH_BLOCK_${mathBlocks.length}__`;
            mathBlocks.push({ math: math.trim(), display: true });
            return placeholder;
        });
        formatted = formatted.replace(/\\\[([\s\S]*?)\\\]/g, (_, math) => {
            const placeholder = `__MATH_BLOCK_${mathBlocks.length}__`;
            mathBlocks.push({ math: math.trim(), display: true });
            return placeholder;
        });
        
        // Protect inline math: $ ... $ or \( ... \)
        formatted = formatted.replace(/\$([^\$\n]+?)\$/g, (_, math) => {
            const placeholder = `__INLINE_MATH_${inlineMath.length}__`;
            inlineMath.push({ math: math.trim(), display: false });
            return placeholder;
        });
        formatted = formatted.replace(/\\\((.+?)\\\)/gs, (_, math) => {
            const placeholder = `__INLINE_MATH_${inlineMath.length}__`;
            inlineMath.push({ math: math.trim(), display: false });
            return placeholder;
        });
        
        // Store code blocks - detect LaTeX inside code blocks and render as math
        const codeBlocks = [];
        formatted = formatted.replace(/```(\w+)?\n?([\s\S]*?)```/g, (_, lang, code) => {
            const trimmedCode = code.trim();
            const language = lang ? lang.toLowerCase() : '';
            
            // Check if this is LaTeX content inside a code block
            const hasLaTeXCommands = /\\(?:frac|sqrt|sum|int|lim|prod|infty|alpha|beta|gamma|delta|epsilon|theta|pi|sigma|omega|phi|psi|lambda|mu|nu|rho|tau|eta|zeta|xi|kappa|chi|pm|mp|times|div|cdot|leq|geq|neq|le|ge|ne|approx|equiv|sim|propto|subset|supset|subseteq|supseteq|cup|cap|in|notin|forall|exists|partial|nabla|vec|hat|bar|dot|ddot|text|mathrm|mathbf|mathit|mathbb|mathcal|left|right|big|Big|bigg|Bigg|begin|end|quad|qquad|rightarrow|leftarrow|Rightarrow|Leftarrow|to|gets)\b/.test(trimmedCode);
            const hasCodePatterns = /(?:function|const|let|var|return|import|export|class|def|if|else|for|while|switch|case|try|catch|=>|===|!==|\|\||&&|console\.|print\(|System\.|public\s|private\s|void\s)/.test(trimmedCode);
            
            const isLaTeX = (language === 'latex' || language === 'tex' || language === 'math') ||
                ((language === '' || language === 'plaintext') && hasLaTeXCommands && !hasCodePatterns);
            
            if (isLaTeX) {
                const placeholder = `__MATH_BLOCK_${mathBlocks.length}__`;
                mathBlocks.push({ math: trimmedCode, display: true });
                return placeholder;
            }
            
            const displayLang = lang ? (LANGUAGE_NAMES[language] || language) : 'plaintext';
            const escapedCode = this.escapeHtml(trimmedCode);
            const placeholder = `__CODE_BLOCK_${codeBlocks.length}__`;
            codeBlocks.push(`<div class="code-block"><div class="code-header"><span class="code-language">${displayLang}</span><button class="code-copy-btn" type="button"><svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><rect x="9" y="9" width="13" height="13" rx="2" ry="2"/><path d="M5 15H4a2 2 0 01-2-2V4a2 2 0 012-2h9a2 2 0 012 2v1"/></svg><span>Copy</span></button></div><div class="code-content"><code>${escapedCode}</code></div></div>`);
            return placeholder;
        });
        
        // Inline code - extract BEFORE auto-formatting
        const inlineCodes = [];
        formatted = formatted.replace(/`([^`]+)`/g, (_, code) => {
            const placeholder = `__INLINE_CODE_${inlineCodes.length}__`;
            inlineCodes.push(`<code>${this.escapeHtml(code)}</code>`);
            return placeholder;
        });
        
        // Apply auto-format math expressions AFTER code blocks are protected
        formatted = this._autoFormatMathExpressions(formatted);
        
        // Tables
        const tablePlaceholders = [];
        formatted = this._parseMarkdownTables(formatted, tablePlaceholders);
        
        // Convert escaped HTML entities to markdown
        formatted = formatted.replace(/&lt;h([1-6])[^&]*&gt;([\s\S]*?)&lt;\/h\1&gt;/gi, (_, level, text) => `${'#'.repeat(parseInt(level))} ${text.trim()}`);
        formatted = formatted.replace(/&lt;strong[^&]*&gt;([\s\S]*?)&lt;\/strong&gt;/gi, '**$1**');
        formatted = formatted.replace(/&lt;b[^&]*&gt;([\s\S]*?)&lt;\/b&gt;/gi, '**$1**');
        formatted = formatted.replace(/&lt;em[^&]*&gt;([\s\S]*?)&lt;\/em&gt;/gi, '*$1*');
        formatted = formatted.replace(/&lt;i[^&]*&gt;([\s\S]*?)&lt;\/i&gt;/gi, '*$1*');
        formatted = formatted.replace(/&lt;u[^&]*&gt;([\s\S]*?)&lt;\/u&gt;/gi, '_$1_');
        formatted = formatted.replace(/&lt;br[^&]*\/?&gt;/gi, '\n');
        formatted = formatted.replace(/&lt;span[^&]*&gt;([\s\S]*?)&lt;\/span&gt;/gi, '$1');
        
        // Handle raw HTML tags
        let prev = '';
        let maxIter = 10;
        while (prev !== formatted && maxIter-- > 0) {
            prev = formatted;
            formatted = formatted.replace(/<h([1-6])[^>]*>([\s\S]*?)<\/h\1>/gi, (_, level, text) => `${'#'.repeat(parseInt(level))} ${text.trim()}`);
            formatted = formatted.replace(/<strong[^>]*>([\s\S]*?)<\/strong>/gi, '**$1**');
            formatted = formatted.replace(/<b[^>]*>([\s\S]*?)<\/b>/gi, '**$1**');
            formatted = formatted.replace(/<em[^>]*>([\s\S]*?)<\/em>/gi, '*$1*');
            formatted = formatted.replace(/<i[^>]*>([\s\S]*?)<\/i>/gi, '*$1*');
            formatted = formatted.replace(/<u[^>]*>([\s\S]*?)<\/u>/gi, '_$1_');
            formatted = formatted.replace(/<br[^>]*\/?>/gi, '\n');
            formatted = formatted.replace(/<span[^>]*>([\s\S]*?)<\/span>/gi, '$1');
        }
        
        // Headings
        formatted = formatted.replace(/^###### (.+)$/gm, (_, text) => `<h6>${this._formatInlineContent(text)}</h6>`);
        formatted = formatted.replace(/^##### (.+)$/gm, (_, text) => `<h5>${this._formatInlineContent(text)}</h5>`);
        formatted = formatted.replace(/^#### (.+)$/gm, (_, text) => `<h4>${this._formatInlineContent(text)}</h4>`);
        formatted = formatted.replace(/^### (.+)$/gm, (_, text) => `<h3>${this._formatInlineContent(text)}</h3>`);
        formatted = formatted.replace(/^## (.+)$/gm, (_, text) => `<h2>${this._formatInlineContent(text)}</h2>`);
        formatted = formatted.replace(/^# (.+)$/gm, (_, text) => `<h1>${this._formatInlineContent(text)}</h1>`);
        
        // Bold, Italic, Underline (use display-safe escaping)
        formatted = formatted.replace(/\*\*([^*]+)\*\*/g, (_, text) => `<strong>${this.escapeHtmlDisplay(text)}</strong>`);
        formatted = formatted.replace(/(?<!\*)\*([^*\n]+)\*(?!\*)/g, (_, text) => `<em>${this.escapeHtmlDisplay(text)}</em>`);
        formatted = formatted.replace(/(?<![_\w])_([^_]+)_(?![_\w])/g, (match, text) => {
            if (/__/.test(match)) return match;
            return `<u>${this.escapeHtmlDisplay(text)}</u>`;
        });
        
        // Lists
        formatted = formatted.replace(/^(\d+)\. (.+)$/gm, (_, num, text) => `<li data-num="${num}">${this._formatInlineContent(text)}</li>`);
        formatted = formatted.replace(/((?:<li data-num="\d+">[\s\S]*?<\/li>\n?)+)/g, '<ol>$1</ol>');
        formatted = formatted.replace(/<\/ol>\n<ol>/g, '');
        formatted = formatted.replace(/ data-num="\d+"/g, '');
        
        formatted = formatted.replace(/^[-*] (.+)$/gm, (_, text) => `<uli>${this._formatInlineContent(text)}</uli>`);
        formatted = formatted.replace(/((?:<uli>[\s\S]*?<\/uli>\n?)+)/g, '<ul>$1</ul>');
        formatted = formatted.replace(/<\/ul>\n<ul>/g, '');
        formatted = formatted.replace(/<uli>/g, '<li>');
        formatted = formatted.replace(/<\/uli>/g, '</li>');
        
        // Blockquotes
        formatted = formatted.replace(/^> (.+)$/gm, (_, text) => `<blockquote>${this._formatInlineContent(text)}</blockquote>`);
        formatted = formatted.replace(/<\/blockquote>\n<blockquote>/g, '<br>');
        
        // Horizontal rule
        formatted = formatted.replace(/^---$/gm, '<hr>');
        formatted = formatted.replace(/^\*\*\*$/gm, '<hr>');
        formatted = formatted.replace(/^___$/gm, '<hr>');
        
        // Links
        formatted = formatted.replace(/\[([^\]]+)\]\(([^)]+)\)/g, (_, text, url) => {
            const safeUrl = this._sanitizeUrl(url);
            if (!safeUrl) return this.escapeHtmlDisplay(text);
            return `<a href="${this.escapeHtml(safeUrl)}" target="_blank" rel="noopener noreferrer">${this.escapeHtmlDisplay(text)}</a>`;
        });
        
        // Paragraphs
        const lines = formatted.split('\n');
        let result = [];
        let paragraphContent = [];
        
        for (const line of lines) {
            const trimmed = line.trim();
            const isBlockElement = /^<(h[1-6]|ul|ol|li|blockquote|hr|div|pre|__CODE|__TABLE|__MATH)/.test(trimmed) ||
                                   /<\/(h[1-6]|ul|ol|blockquote|div|pre)>$/.test(trimmed);
            
            if (isBlockElement || trimmed === '') {
                if (paragraphContent.length > 0) {
                    result.push('<p>' + paragraphContent.join('<br>') + '</p>');
                    paragraphContent = [];
                }
                if (trimmed !== '') result.push(line);
            } else {
                paragraphContent.push(trimmed);
            }
        }
        
        if (paragraphContent.length > 0) {
            result.push('<p>' + paragraphContent.join('<br>') + '</p>');
        }
        
        formatted = result.join('\n');
        
        // Restore placeholders
        inlineCodes.forEach((code, i) => {
            formatted = formatted.replace(new RegExp(`__INLINE_CODE_${i}__`, 'g'), code);
        });
        codeBlocks.forEach((block, i) => {
            formatted = formatted.replace(new RegExp(`__CODE_BLOCK_${i}__`, 'g'), block);
        });
        tablePlaceholders.forEach((table, i) => {
            formatted = formatted.replace(new RegExp(`__TABLE_BLOCK_${i}__`, 'g'), table);
        });
        mathBlocks.forEach((item, i) => {
            const rendered = this._renderMath(item.math, true);
            formatted = formatted.replace(new RegExp(`__MATH_BLOCK_${i}__`, 'g'), rendered);
        });
        inlineMath.forEach((item, i) => {
            const rendered = this._renderMath(item.math, false);
            formatted = formatted.replace(new RegExp(`__INLINE_MATH_${i}__`, 'g'), rendered);
        });
        
        // Clean up
        formatted = formatted.replace(/<p><br><\/p>/g, '');
        formatted = formatted.replace(/<p>\s*<\/p>/g, '');
        
        // Final pass for remaining escaped HTML entities
        formatted = formatted.replace(/&lt;\s*h([1-6])\s*&gt;([\s\S]*?)&lt;\s*\/\s*h\1\s*&gt;/gi, (_, level, text) => `<h${level}>${text.trim()}</h${level}>`);
        formatted = formatted.replace(/&lt;\s*strong\s*&gt;([\s\S]*?)&lt;\s*\/\s*strong\s*&gt;/gi, '<strong>$1</strong>');
        formatted = formatted.replace(/&lt;\s*em\s*&gt;([\s\S]*?)&lt;\s*\/\s*em\s*&gt;/gi, '<em>$1</em>');
        formatted = formatted.replace(/&lt;\s*br\s*\/?&gt;/gi, '<br>');
        formatted = formatted.replace(/&lt;\s*hr\s*\/?&gt;/gi, '<hr>');
        
        return formatted;
    }

    _formatInlineContent(text) {
        if (!text) return '';
        let result = text;
        
        // Convert escaped HTML entities to markdown
        result = result.replace(/&lt;strong[^&]*&gt;([\s\S]*?)&lt;\/strong&gt;/gi, '**$1**');
        result = result.replace(/&lt;b[^&]*&gt;([\s\S]*?)&lt;\/b&gt;/gi, '**$1**');
        result = result.replace(/&lt;em[^&]*&gt;([\s\S]*?)&lt;\/em&gt;/gi, '*$1*');
        result = result.replace(/&lt;i[^&]*&gt;([\s\S]*?)&lt;\/i&gt;/gi, '*$1*');
        result = result.replace(/&lt;u[^&]*&gt;([\s\S]*?)&lt;\/u&gt;/gi, '_$1_');
        result = result.replace(/&lt;span[^&]*&gt;([\s\S]*?)&lt;\/span&gt;/gi, '$1');
        
        // Handle raw HTML tags
        let prev = '';
        let maxIter = 10;
        while (prev !== result && maxIter-- > 0) {
            prev = result;
            result = result.replace(/<strong[^>]*>([\s\S]*?)<\/strong>/gi, '**$1**');
            result = result.replace(/<b[^>]*>([\s\S]*?)<\/b>/gi, '**$1**');
            result = result.replace(/<em[^>]*>([\s\S]*?)<\/em>/gi, '*$1*');
            result = result.replace(/<i[^>]*>([\s\S]*?)<\/i>/gi, '*$1*');
            result = result.replace(/<u[^>]*>([\s\S]*?)<\/u>/gi, '_$1_');
            result = result.replace(/<span[^>]*>([\s\S]*?)<\/span>/gi, '$1');
        }
        
        // Store bold/italic with unique markers
        const bolds = [];
        const italics = [];
        const underlines = [];
        const boldMarker = '\u0000BOLD\u0000';
        const italicMarker = '\u0000ITALIC\u0000';
        const underlineMarker = '\u0000UNDERLINE\u0000';
        
        result = result.replace(/\*\*([^*]+)\*\*/g, (_, content) => {
            bolds.push(content);
            return `${boldMarker}${bolds.length - 1}${boldMarker}`;
        });
        
        result = result.replace(/(?<!\*)\*([^*]+)\*(?!\*)/g, (_, content) => {
            italics.push(content);
            return `${italicMarker}${italics.length - 1}${italicMarker}`;
        });
        
        result = result.replace(/(?<![_\w])_([^_]+)_(?![_\w])/g, (match, content) => {
            if (/__/.test(match)) return match;
            underlines.push(content);
            return `${underlineMarker}${underlines.length - 1}${underlineMarker}`;
        });
        
        // Escape for XSS protection
        result = this.escapeHtmlDisplay(result);
        
        // Restore bold with proper HTML
        bolds.forEach((content, i) => {
            result = result.replace(new RegExp(`${boldMarker}${i}${boldMarker}`, 'g'), `<strong>${this.escapeHtmlDisplay(content)}</strong>`);
        });
        
        // Restore italic with proper HTML
        italics.forEach((content, i) => {
            result = result.replace(new RegExp(`${italicMarker}${i}${italicMarker}`, 'g'), `<em>${this.escapeHtmlDisplay(content)}</em>`);
        });
        
        // Restore underline with proper HTML
        underlines.forEach((content, i) => {
            result = result.replace(new RegExp(`${underlineMarker}${i}${underlineMarker}`, 'g'), `<u>${this.escapeHtmlDisplay(content)}</u>`);
        });
        
        return result;
    }

    _renderMath(math, displayMode = false) {
        if (!math) return '';
        
        try {
            // Check if KaTeX is available (global scope)
            const katexLib = typeof katex !== 'undefined' ? katex : (typeof window !== 'undefined' ? window.katex : null);
            
            if (katexLib && typeof katexLib.renderToString === 'function') {
                const html = katexLib.renderToString(math, {
                    displayMode: displayMode,
                    throwOnError: false,
                    errorColor: '#cc0000',
                    strict: false,
                    trust: true,
                    macros: {
                        "\\R": "\\mathbb{R}",
                        "\\N": "\\mathbb{N}",
                        "\\Z": "\\mathbb{Z}",
                        "\\Q": "\\mathbb{Q}",
                        "\\C": "\\mathbb{C}"
                    }
                });
                
                if (displayMode) {
                    return `<div class="math-block">${html}</div>`;
                }
                return `<span class="math-inline">${html}</span>`;
            }
        } catch (e) {
            console.warn('KaTeX rendering failed:', e);
        }
        
        // Fallback: convert common LaTeX to Unicode
        let fallback = math
            // Handle \text{} - extract text content
            .replace(/\\text\{([^}]+)\}/g, (_, text) => text.replace(/_/g, ' '))
            .replace(/\\textit\{([^}]+)\}/g, '$1')
            .replace(/\\textbf\{([^}]+)\}/g, '$1')
            .replace(/\\mathrm\{([^}]+)\}/g, '$1')
            .replace(/\\mathit\{([^}]+)\}/g, '$1')
            .replace(/\\mathbf\{([^}]+)\}/g, '$1')
            // Remove \left and \right (sizing hints)
            .replace(/\\left\s*/g, '')
            .replace(/\\right\s*/g, '')
            .replace(/\\big\s*/g, '')
            .replace(/\\Big\s*/g, '')
            .replace(/\\bigg\s*/g, '')
            .replace(/\\Bigg\s*/g, '')
            // Fractions
            .replace(/\\frac\{([^}]+)\}\{([^}]+)\}/g, '($1/$2)')
            .replace(/\\dfrac\{([^}]+)\}\{([^}]+)\}/g, '($1/$2)')
            .replace(/\\sqrt\{([^}]+)\}/g, '√($1)')
            .replace(/\\sqrt(\d+)/g, '√$1')
            .replace(/\\int_\{?([^}\s]+)\}?\^\{?([^}\s]+)\}?/g, '∫[$1→$2]')
            .replace(/\\int/g, '∫')
            .replace(/\\sum_\{?([^}\s]+)\}?\^\{?([^}\s]+)\}?/g, 'Σ[$1→$2]')
            .replace(/\\sum/g, 'Σ')
            .replace(/\\prod/g, '∏')
            .replace(/\\partial/g, '∂')
            .replace(/\\nabla/g, '∇')
            .replace(/\\infty/g, '∞')
            .replace(/\\alpha/g, 'α').replace(/\\beta/g, 'β').replace(/\\gamma/g, 'γ')
            .replace(/\\delta/g, 'δ').replace(/\\Delta/g, 'Δ')
            .replace(/\\epsilon/g, 'ε').replace(/\\varepsilon/g, 'ε')
            .replace(/\\theta/g, 'θ').replace(/\\Theta/g, 'Θ')
            .replace(/\\lambda/g, 'λ').replace(/\\Lambda/g, 'Λ')
            .replace(/\\mu/g, 'μ').replace(/\\nu/g, 'ν')
            .replace(/\\pi/g, 'π').replace(/\\Pi/g, 'Π')
            .replace(/\\sigma/g, 'σ').replace(/\\Sigma/g, 'Σ')
            .replace(/\\omega/g, 'ω').replace(/\\Omega/g, 'Ω')
            .replace(/\\phi/g, 'φ').replace(/\\Phi/g, 'Φ')
            .replace(/\\psi/g, 'ψ').replace(/\\Psi/g, 'Ψ')
            .replace(/\\rho/g, 'ρ').replace(/\\tau/g, 'τ')
            .replace(/\\eta/g, 'η').replace(/\\zeta/g, 'ζ')
            .replace(/\\xi/g, 'ξ').replace(/\\Xi/g, 'Ξ')
            .replace(/\\kappa/g, 'κ').replace(/\\iota/g, 'ι')
            .replace(/\\chi/g, 'χ').replace(/\\upsilon/g, 'υ')
            .replace(/\\times/g, '×').replace(/\\div/g, '÷').replace(/\\pm/g, '±')
            .replace(/\\mp/g, '∓').replace(/\\cdot/g, '·')
            .replace(/\\leq/g, '≤').replace(/\\geq/g, '≥').replace(/\\neq/g, '≠')
            .replace(/\\le/g, '≤').replace(/\\ge/g, '≥').replace(/\\ne/g, '≠')
            .replace(/\\approx/g, '≈').replace(/\\equiv/g, '≡')
            .replace(/\\propto/g, '∝').replace(/\\sim/g, '∼')
            .replace(/\\rightarrow/g, '→').replace(/\\leftarrow/g, '←')
            .replace(/\\Rightarrow/g, '⇒').replace(/\\Leftarrow/g, '⇐')
            .replace(/\\leftrightarrow/g, '↔').replace(/\\Leftrightarrow/g, '⇔')
            .replace(/\\to/g, '→').replace(/\\gets/g, '←')
            .replace(/\\forall/g, '∀').replace(/\\exists/g, '∃')
            .replace(/\\in/g, '∈').replace(/\\notin/g, '∉')
            .replace(/\\subset/g, '⊂').replace(/\\supset/g, '⊃')
            .replace(/\\subseteq/g, '⊆').replace(/\\supseteq/g, '⊇')
            .replace(/\\cup/g, '∪').replace(/\\cap/g, '∩')
            .replace(/\\emptyset/g, '∅').replace(/\\varnothing/g, '∅')
            .replace(/\\land/g, '∧').replace(/\\lor/g, '∨').replace(/\\neg/g, '¬')
            .replace(/\\angle/g, '∠').replace(/\\perp/g, '⊥').replace(/\\parallel/g, '∥')
            .replace(/\\ldots/g, '…').replace(/\\cdots/g, '⋯')
            // Spacing
            .replace(/\\,/g, ' ').replace(/\\;/g, ' ').replace(/\\:/g, ' ')
            .replace(/\\!/g, '').replace(/\\quad/g, '  ').replace(/\\qquad/g, '    ')
            .replace(/\\ /g, ' ')
            // Remove remaining LaTeX commands but keep content in braces
            .replace(/\\[a-zA-Z]+\{([^}]*)\}/g, '$1')
            .replace(/\\[a-zA-Z]+/g, '')
            .replace(/\{([^{}]*)\}/g, '$1');
        
        // Handle superscripts and subscripts with iterative processing
        for (let i = 0; i < 5; i++) {
            fallback = fallback.replace(/\^(\{[^{}]+\})/g, (_, exp) => {
                const content = exp.slice(1, -1);
                return content.split('').map(c => SUPERSCRIPTS[c] || SUPERSCRIPTS[c.toLowerCase()] || c).join('');
            });
            fallback = fallback.replace(/\^([0-9a-zA-Z+\-])/g, (_, c) => {
                return SUPERSCRIPTS[c] || SUPERSCRIPTS[c.toLowerCase()] || `^${c}`;
            });
            fallback = fallback.replace(/_(\{[^{}]+\})/g, (_, exp) => {
                const content = exp.slice(1, -1);
                return content.split('').map(c => SUBSCRIPTS[c] || SUBSCRIPTS[c.toLowerCase()] || c).join('');
            });
            fallback = fallback.replace(/_([0-9a-zA-Z])/g, (_, c) => {
                return SUBSCRIPTS[c] || SUBSCRIPTS[c.toLowerCase()] || `_${c}`;
            });
        }
        
        // Final cleanup
        fallback = fallback.replace(/[{}]/g, '');
        
        if (displayMode) {
            return `<div class="math-block math-fallback">${this.escapeHtmlDisplay(fallback)}</div>`;
        }
        return `<span class="math-inline math-fallback">${this.escapeHtmlDisplay(fallback)}</span>`;
    }

    _parseMarkdownTables(content, placeholders) {
        if (!content) return content;
        
        const lines = content.split('\n');
        const result = [];
        let i = 0;
        
        while (i < lines.length) {
            const line = lines[i];
            
            if (line.trim().startsWith('|') && line.trim().endsWith('|')) {
                const nextLine = lines[i + 1];
                if (nextLine && /^\|[\s:|-]+\|$/.test(nextLine.trim())) {
                    const tableLines = [line];
                    let j = i + 1;
                    
                    while (j < lines.length && lines[j].trim().startsWith('|')) {
                        tableLines.push(lines[j]);
                        j++;
                    }
                    
                    const tableHtml = this._convertTableToHtml(tableLines);
                    if (tableHtml) {
                        const placeholder = `__TABLE_BLOCK_${placeholders.length}__`;
                        placeholders.push(tableHtml);
                        result.push(placeholder);
                        i = j;
                        continue;
                    }
                }
            }
            
            result.push(line);
            i++;
        }
        
        return result.join('\n');
    }

    _convertTableToHtml(lines) {
        if (lines.length < 2) return null;
        
        const headerLine = lines[0].trim();
        const headerCells = headerLine.split('|').filter(c => c.trim()).map(c => c.trim());
        
        const separatorLine = lines[1].trim();
        const aligns = separatorLine.split('|').filter(c => c.trim()).map(c => {
            const cell = c.trim();
            if (cell.startsWith(':') && cell.endsWith(':')) return 'center';
            if (cell.endsWith(':')) return 'right';
            return 'left';
        });
        
        let html = '<div class="table-wrapper"><table><thead><tr>';
        headerCells.forEach((h, i) => {
            html += `<th style="text-align:${aligns[i] || 'left'}">${this._formatInlineContent(h)}</th>`;
        });
        html += '</tr></thead><tbody>';
        
        for (let i = 2; i < lines.length; i++) {
            const cells = lines[i].split('|').filter(c => c !== '').map(c => c.trim());
            html += '<tr>';
            cells.forEach((c, j) => {
                if (c !== undefined) {
                    html += `<td style="text-align:${aligns[j] || 'left'}">${this._formatInlineContent(c)}</td>`;
                }
            });
            html += '</tr>';
        }
        
        html += '</tbody></table></div>';
        return html;
    }

    _initCodeCopyButtons() {
        this.messagesArea?.querySelectorAll('.code-copy-btn').forEach(btn => {
            btn.addEventListener('click', async () => {
                const codeBlock = btn.closest('.code-block');
                const code = codeBlock?.querySelector('code')?.textContent;
                
                if (code) {
                    try {
                        await navigator.clipboard.writeText(code);
                        btn.classList.add('copied');
                        btn.querySelector('span').textContent = 'Copied!';
                        setTimeout(() => {
                            btn.classList.remove('copied');
                            btn.querySelector('span').textContent = 'Copy';
                        }, 2000);
                    } catch (err) {
                        console.error('Failed to copy:', err);
                    }
                }
            });
        });
    }

    // ==================== USER INTERACTIONS ====================
    _selectUser(ip) {
        this.currentUser = ip;
        this.currentChat = null;
        this.selectedUserName.textContent = this._maskIp(ip);
        
        // Update breadcrumb
        this._updateBreadcrumb(['Dashboard', `User: ${this._maskIp(ip)}`]);
        
        // Update chat count badge
        const user = this.users.find(u => u.ip === ip);
        if (this.chatCountBadge && this.chatCount && user) {
            this.chatCount.textContent = user.chatCount || 0;
            this.chatCountBadge.style.display = 'flex';
        }
        
        // Render user details panel
        if (user) {
            this._renderUserDetailsPanel(user);
        }
        
        // Update active state
        this.userList.querySelectorAll('.user-card').forEach(card => {
            card.classList.toggle('active', card.dataset.ip === ip);
        });
        
        // Load chats
        this._loadUserChats(ip);
        
        // Clear messages
        this.chatHeader.style.display = 'none';
        this.messagesArea.innerHTML = `
            <div class="empty-state">
                <svg width="64" height="64" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.5">
                    <path d="M21 15a2 2 0 01-2 2H7l-4 4V5a2 2 0 012-2h14a2 2 0 012 2z"/>
                </svg>
                <p>Select a chat to view messages</p>
            </div>
        `;
        
        // On mobile, close sidebar and show chats panel
        if (window.innerWidth <= 768) {
            this._closeSidebar();
            this._openChatsPanel();
        }
    }
    
    _selectChat(chatId) {
        this.currentChat = chatId;
        
        // Update breadcrumb
        const chat = this.chats.find(c => c.id === chatId);
        const chatTitle = chat?.title || 'Chat';
        this._updateBreadcrumb(['Dashboard', `User: ${this._maskIp(this.currentUser)}`, chatTitle]);
        
        // Update active state
        this.chatsList.querySelectorAll('.chat-card').forEach(card => {
            card.classList.toggle('active', card.dataset.id === chatId);
        });
        
        // Load messages
        this._loadChatMessages(chatId);
        
        // On mobile, hide chats panel
        if (window.innerWidth <= 768) {
            this._closeChatsPanel();
        }
    }
    
    _updateBreadcrumb(items) {
        if (!this.breadcrumb) return;
        
        const html = items.map((item, index) => {
            const isLast = index === items.length - 1;
            const isClickable = index < items.length - 1;
            
            let breadcrumbHtml = `<span class="breadcrumb-item ${isLast ? 'active' : ''}" ${isClickable ? 'data-level="' + index + '"' : ''}>${item}</span>`;
            
            if (!isLast) {
                breadcrumbHtml += '<span class="breadcrumb-separator"></span>';
            }
            
            return breadcrumbHtml;
        }).join('');
        
        this.breadcrumb.innerHTML = html;
        
        // Add click handlers for navigation
        this.breadcrumb.querySelectorAll('.breadcrumb-item[data-level]').forEach(item => {
            item.addEventListener('click', () => {
                const level = parseInt(item.dataset.level);
                this._navigateToBreadcrumbLevel(level);
            });
        });
    }
    
    _navigateToBreadcrumbLevel(level) {
        if (level === 0) {
            // Navigate to dashboard
            this.currentUser = null;
            this.currentChat = null;
            this.selectedUserName.textContent = '-';
            this._updateBreadcrumb(['Dashboard']);
            
            if (this.chatCountBadge) {
                this.chatCountBadge.style.display = 'none';
            }
            
            // Clear active states
            this.userList.querySelectorAll('.user-card').forEach(card => {
                card.classList.remove('active');
            });
            
            // Clear chats and messages
            this.chatsList.innerHTML = '<div class="empty-state"><p>Select a user to view chats</p></div>';
            this.messagesArea.innerHTML = '<div class="empty-state"><p>Select a chat to view messages</p></div>';
            this.chatHeader.style.display = 'none';
        } else if (level === 1 && this.currentUser) {
            // Navigate back to user level
            this.currentChat = null;
            this._updateBreadcrumb(['Dashboard', `User: ${this._maskIp(this.currentUser)}`]);
            
            // Clear chat selection
            this.chatsList.querySelectorAll('.chat-card').forEach(card => {
                card.classList.remove('active');
            });
            
            // Clear messages
            this.messagesArea.innerHTML = '<div class="empty-state"><p>Select a chat to view messages</p></div>';
            this.chatHeader.style.display = 'none';
        }
    }

    _filterUsers(query) {
        const q = query.toLowerCase().trim();
        let visibleCount = 0;
        
        this.userList.querySelectorAll('.user-card').forEach(card => {
            const ip = card.dataset.ip.toLowerCase();
            const deviceText = Array.from(card.querySelectorAll('.user-badge'))
                .map(badge => badge.textContent.toLowerCase()).join(' ');
            
            const isVisible = ip.includes(q) || deviceText.includes(q);
            card.style.display = isVisible ? '' : 'none';
            
            if (isVisible) {
                visibleCount++;
                // Highlight matching text
                this._highlightSearchText(card, q);
            }
        });
        
        // Update search results counter
        if (this.searchResultsCount) {
            if (q && visibleCount > 0) {
                this.searchResultsCount.textContent = visibleCount;
                this.searchResultsCount.style.display = 'block';
            } else {
                this.searchResultsCount.style.display = 'none';
            }
        }
        
        // Show search results count
        if (q && visibleCount === 0) {
            this.userList.innerHTML += '<div class="no-data">No users match your search</div>';
        }
    }
    
    _highlightSearchText(element, query) {
        if (!query) return;
        
        const textNodes = this._getTextNodes(element);
        textNodes.forEach(node => {
            const text = node.textContent;
            const regex = new RegExp(`(${this.escapeRegex(query)})`, 'gi');
            if (regex.test(text)) {
                const highlightedText = text.replace(regex, '<mark>$1</mark>');
                const wrapper = document.createElement('span');
                wrapper.innerHTML = highlightedText;
                node.parentNode.replaceChild(wrapper, node);
            }
        });
    }
    
    _getTextNodes(element) {
        const textNodes = [];
        const walker = document.createTreeWalker(
            element,
            NodeFilter.SHOW_TEXT,
            null,
            false
        );
        
        let node;
        while (node = walker.nextNode()) {
            if (node.textContent.trim()) {
                textNodes.push(node);
            }
        }
        return textNodes;
    }
    
    escapeRegex(string) {
        return string.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
    }

    _switchTab(tab) {
        // Add smooth transition feedback
        const currentTab = document.querySelector('.tab-btn.active');
        if (currentTab) {
            currentTab.style.transform = 'scale(0.95)';
            setTimeout(() => {
                currentTab.style.transform = '';
            }, 150);
        }
        
        this.tabBtns.forEach(btn => {
            const isActive = btn.dataset.tab === tab;
            btn.classList.toggle('active', isActive);
            
            if (isActive) {
                btn.style.transform = 'scale(1.05)';
                setTimeout(() => {
                    btn.style.transform = '';
                }, 150);
            }
        });
        
        // Smooth content transition
        const fadeOut = (element) => {
            if (element) {
                element.style.opacity = '0';
                element.style.transform = 'translateY(10px)';
            }
        };
        
        const fadeIn = (element) => {
            if (element) {
                setTimeout(() => {
                    element.style.display = '';
                    element.style.opacity = '1';
                    element.style.transform = 'translateY(0)';
                }, 150);
            }
        };
        
        if (tab === 'users') {
            fadeOut(this.statsTab);
            setTimeout(() => {
                this.statsTab.style.display = 'none';
                fadeIn(this.usersTab);
            }, 150);
        } else {
            fadeOut(this.usersTab);
            setTimeout(() => {
                this.usersTab.style.display = 'none';
                fadeIn(this.statsTab);
            }, 150);
        }
    }

    _toggleSidebar() {
        this.sidebar.classList.toggle('open');
        this.sidebarOverlay.classList.toggle('active');
        // Prevent body scroll when sidebar is open on mobile
        document.body.style.overflow = this.sidebar.classList.contains('open') ? 'hidden' : '';
    }

    _closeSidebar() {
        this.sidebar.classList.remove('open');
        this.sidebarOverlay.classList.remove('active');
        document.body.style.overflow = '';
    }

    _openChatsPanel() {
        this.chatsPanel?.classList.add('open');
        this.chatsPanelOverlay?.classList.add('active');
        document.body.style.overflow = 'hidden';
    }

    _closeChatsPanel() {
        this.chatsPanel?.classList.remove('open');
        this.chatsPanelOverlay?.classList.remove('active');
        document.body.style.overflow = '';
    }

    // ==================== ENHANCED ACTIONS ====================
    async _refreshData() {
        if (this.refreshBtn) {
            this.refreshBtn.disabled = true;
            this.refreshBtn.classList.add('spinning');
        }
        
        try {
            // Show context-aware loading
            this._setLoadingState(true, 'refresh');
            
            await this._loadData();
            
            // Refresh current user's chats if selected
            if (this.currentUser) {
                await this._loadUserChats(this.currentUser);
            }
            
            // Refresh current chat messages if selected
            if (this.currentChat) {
                await this._loadChatMessages(this.currentChat);
            }
            
            this._showToast('Data refreshed successfully', 'success', 3000);
        } catch (err) {
            console.error('Refresh failed:', err);
            this._showToast('Failed to refresh data', 'error');
        } finally {
            this._setLoadingState(false);
            if (this.refreshBtn) {
                this.refreshBtn.disabled = false;
                this.refreshBtn.classList.remove('spinning');
                this.refreshBtn.querySelector('span').textContent = 'Refresh';
            }
        }
    }
    
    // Enhanced keyboard shortcuts
    _initKeyboardShortcuts() {
        document.addEventListener('keydown', (e) => {
            // Only handle shortcuts when not typing in inputs
            if (e.target.tagName === 'INPUT' || e.target.tagName === 'TEXTAREA') return;
            
            switch (e.key) {
                case 'Escape':
                    this._hideDialog();
                    this._hideHelp();
                    this._closeSidebar();
                    this._closeChatsPanel();
                    break;
                case 'r':
                case 'R':
                    if (e.ctrlKey || e.metaKey) {
                        e.preventDefault();
                        this._refreshData();
                    }
                    break;
                case 'f':
                case 'F':
                    if (e.ctrlKey || e.metaKey) {
                        e.preventDefault();
                        this.userSearch?.focus();
                    }
                    break;
                case '1':
                    if (e.ctrlKey || e.metaKey) {
                        e.preventDefault();
                        this._switchTab('users');
                    }
                    break;
                case '2':
                    if (e.ctrlKey || e.metaKey) {
                        e.preventDefault();
                        this._switchTab('stats');
                    }
                    break;
            }
        });
    }

    // ==================== EXPORT FUNCTIONS ====================
    _toggleExportDropdown(e) {
        e.stopPropagation();
        this.exportDropdown?.classList.toggle('open');
    }

    async _exportJson() {
        this.exportDropdown?.classList.remove('open');
        try {
            const response = await fetch(`${API_BASE}/export?format=json`, {
                headers: { 'Authorization': `Bearer ${this.token}` }
            });
            
            if (!response.ok) throw new Error('Export failed');
            
            const blob = await response.blob();
            const url = URL.createObjectURL(blob);
            const a = document.createElement('a');
            a.href = url;
            a.download = `rox-admin-export-${new Date().toISOString().slice(0, 10)}.json`;
            a.click();
            URL.revokeObjectURL(url);
            
            this._showToast('JSON export downloaded', 'success');
        } catch (err) {
            this._showToast('Export failed', 'error');
        }
    }

    _exportStatsPdf() {
        this.exportDropdown?.classList.remove('open');
        const s = this.stats;
        const now = new Date();
        const dateStr = now.toLocaleDateString('en-US', { year: 'numeric', month: 'long', day: 'numeric' });
        const timeStr = now.toLocaleTimeString('en-US', { hour: '2-digit', minute: '2-digit' });
        
        // Build model usage HTML
        let modelUsageHtml = '';
        if (s.modelUsage && Object.keys(s.modelUsage).length > 0) {
            const total = Object.values(s.modelUsage).reduce((a, b) => a + b, 0) || 1;
            modelUsageHtml = Object.entries(s.modelUsage).map(([model, count]) => {
                const percent = Math.round((count / total) * 100);
                return `<div class="usage-row"><span class="usage-label">${this.escapeHtml(model)}</span><div class="usage-bar"><div class="usage-fill" style="width:${percent}%"></div></div><span class="usage-value">${count} (${percent}%)</span></div>`;
            }).join('');
        }
        
        const pdfHtml = this._getPdfTemplate('Rox AI Admin Report', dateStr, timeStr, `
            <div class="stats-grid">
                <div class="stat-card"><div class="stat-value">${s.totalUsers || 0}</div><div class="stat-label">Total Users</div></div>
                <div class="stat-card"><div class="stat-value">${s.totalChats || 0}</div><div class="stat-label">Total Chats</div></div>
                <div class="stat-card"><div class="stat-value">${s.todayQueries || 0}</div><div class="stat-label">Today's Queries</div></div>
                <div class="stat-card"><div class="stat-value">${s.totalMessages || 0}</div><div class="stat-label">Total Messages</div></div>
                <div class="stat-card"><div class="stat-value">${s.activeSessions || 0}</div><div class="stat-label">Active Sessions</div></div>
                <div class="stat-card"><div class="stat-value">${s.avgResponseTime || 0}ms</div><div class="stat-label">Avg Response Time</div></div>
            </div>
            ${modelUsageHtml ? `<h2>Model Usage</h2><div class="model-usage">${modelUsageHtml}</div>` : ''}
        `);
        
        this._printPdf(pdfHtml);
        this._showToast('Stats PDF ready - uncheck "Headers and footers" in print options', 'success');
    }

    _exportUsersPdf() {
        this.exportDropdown?.classList.remove('open');
        const now = new Date();
        const dateStr = now.toLocaleDateString('en-US', { year: 'numeric', month: 'long', day: 'numeric' });
        const timeStr = now.toLocaleTimeString('en-US', { hour: '2-digit', minute: '2-digit' });
        
        const usersHtml = this.users.map(user => `
            <tr>
                <td>${this.escapeHtml(this._maskIp(user.ip))}</td>
                <td>${this.escapeHtml(user.device?.browser || '-')}</td>
                <td>${this.escapeHtml(user.device?.os || '-')}</td>
                <td>${user.chatCount || 0}</td>
                <td><span class="status-badge ${user.isOnline ? 'online' : ''}">${user.isOnline ? 'Online' : 'Offline'}</span></td>
                <td>${this.escapeHtml(this._formatTimeAgo(user.lastActivity))}</td>
            </tr>
        `).join('');
        
        const pdfHtml = this._getPdfTemplate('Rox AI Users Report', dateStr, timeStr, `
            <p class="summary">Total Users: <strong>${this.users.length}</strong></p>
            <table>
                <thead>
                    <tr>
                        <th>IP Address</th>
                        <th>Browser</th>
                        <th>OS</th>
                        <th>Chats</th>
                        <th>Status</th>
                        <th>Last Active</th>
                    </tr>
                </thead>
                <tbody>${usersHtml}</tbody>
            </table>
        `);
        
        this._printPdf(pdfHtml);
        this._showToast('Users PDF ready - uncheck "Headers and footers" in print options', 'success');
    }

    _exportChatJson() {
        if (!this.currentChat) {
            this._showToast('No chat selected', 'error');
            return;
        }
        
        const chat = this.chats.find(c => c.id === this.currentChat);
        if (!chat) {
            this._showToast('Chat not found', 'error');
            return;
        }
        
        const data = {
            chatId: this.currentChat,
            title: chat.title,
            exportedAt: new Date().toISOString(),
            messageCount: chat.messageCount,
            messages: this._currentMessages || []
        };
        
        const blob = new Blob([JSON.stringify(data, null, 2)], { type: 'application/json' });
        const url = URL.createObjectURL(blob);
        const a = document.createElement('a');
        a.href = url;
        a.download = `chat-${this.currentChat.slice(0, 8)}-${new Date().toISOString().slice(0, 10)}.json`;
        a.click();
        URL.revokeObjectURL(url);
        
        this._showToast('Chat JSON downloaded', 'success');
    }

    _exportChatPdf() {
        if (!this.currentChat || !this._currentMessages?.length) {
            this._showToast('No chat selected or no messages', 'error');
            return;
        }
        
        const chat = this.chats.find(c => c.id === this.currentChat);
        const now = new Date();
        const dateStr = now.toLocaleDateString('en-US', { year: 'numeric', month: 'long', day: 'numeric' });
        const timeStr = now.toLocaleTimeString('en-US', { hour: '2-digit', minute: '2-digit' });
        
        // Format messages with proper markdown rendering
        const messagesHtml = this._currentMessages.map(msg => {
            const isUser = msg.role === 'user';
            const time = msg.timestamp ? new Date(msg.timestamp).toLocaleString() : '';
            const model = msg.model || '';
            const formattedContent = this._formatContentForPdf(msg.content || '');
            
            return `
                <div class="message ${isUser ? 'user' : 'assistant'}">
                    <div class="message-header">
                        <span class="role-badge ${isUser ? 'user-badge' : 'ai-badge'}">${isUser ? 'USER' : 'ROX AI'}</span>
                        <span class="message-meta">${time}${model ? ` • ${this.escapeHtml(model)}` : ''}</span>
                    </div>
                    <div class="message-content">${formattedContent}</div>
                </div>
            `;
        }).join('');
        
        const pdfHtml = this._getPdfTemplate(
            chat?.title || 'Chat Export', 
            dateStr, 
            timeStr, 
            `<p class="summary">${this._currentMessages.length} messages</p><div class="messages">${messagesHtml}</div>`,
            true // isChat flag for chat-specific styles
        );
        
        this._printPdf(pdfHtml);
        this._showToast('Chat PDF ready - uncheck "Headers and footers" in print options', 'success');
    }

    // Format content for PDF with proper markdown rendering (same approach as main app.js)
    _formatContentForPdf(content) {
        if (!content || typeof content !== 'string') return '';
        let formatted = content;
        
        // Remove internet search indicator lines
        formatted = formatted.replace(/^🌐\s*Searching for.*?\.\.\.?\s*$/gm, '');
        formatted = formatted.replace(/^🌐\s*LIVE INTERNET SEARCH RESULTS:?\s*$/gm, '');
        formatted = formatted.replace(/^\s*\n+/g, '').replace(/\n{3,}/g, '\n\n');
        
        // ==================== COMPREHENSIVE NUMBER-TEXT SPACING FIX ====================
        // This fixes ALL cases where numbers are attached to text without proper spacing
        
        // STEP 1: Fix numbered list items at start of lines
        // Handle "1AI" -> "1. AI" (number + uppercase letter)
        formatted = formatted.replace(/^(\d+)([A-Z][a-zA-Z])/gm, '$1. $2');
        // Handle "1**text**" -> "1. **text**" (number + bold markdown)
        formatted = formatted.replace(/^(\d+)(\*\*[^*]+\*\*)/gm, '$1. $2');
        // Handle "1text" -> "1. text" (number + any letter at line start)
        formatted = formatted.replace(/^(\d+)([a-zA-Z])/gm, '$1. $2');
        // Handle "1.text" -> "1. text" (dot but no space)
        formatted = formatted.replace(/^(\d+)\.([^\s\d])/gm, '$1. $2');
        // Handle "1)" -> "1. " (parenthesis style to dot style)
        formatted = formatted.replace(/^(\d+)\)\s*/gm, '$1. ');
        // Handle "1-" -> "1. " (dash style to dot style)
        formatted = formatted.replace(/^(\d+)-\s*/gm, '$1. ');
        
        // STEP 2: Fix numbers attached to words ANYWHERE in text (not just line start)
        // This catches cases like "Cost1Use" -> "Cost 1. Use" or inline "see step1for" -> "see step 1 for"
        // Pattern: word boundary + number + letter (not at line start)
        formatted = formatted.replace(/(\s)(\d+)([A-Z][a-zA-Z])/g, '$1$2. $3');
        formatted = formatted.replace(/(\s)(\d+)([a-z])/g, '$1$2. $3');
        
        // STEP 3: Fix specific patterns seen in the screenshot
        // "Word1Word" -> "Word 1. Word" (word + number + word)
        formatted = formatted.replace(/([a-zA-Z])(\d+)([A-Z][a-zA-Z])/g, '$1\n$2. $3');
        // "word1word" -> "word 1. word" (lowercase word + number + lowercase word)
        formatted = formatted.replace(/([a-z])(\d+)([a-z])/g, '$1 $2. $3');
        
        // STEP 4: Fix bullet points without space
        formatted = formatted.replace(/^-([A-Za-z])/gm, '- $1');
        formatted = formatted.replace(/^\*([A-Za-z])/gm, '* $1');
        formatted = formatted.replace(/^•([A-Za-z])/gm, '• $1');
        
        // STEP 5: Ensure proper spacing after list markers
        // "1.Word" -> "1. Word"
        formatted = formatted.replace(/^(\d+)\.([A-Za-z])/gm, '$1. $2');
        // "-Word" -> "- Word"
        formatted = formatted.replace(/^-([A-Za-z])/gm, '- $1');
        
        // STEP 6: Fix "For Word" type headers followed by numbered lists
        // Pattern: "For Something\n1Text" -> "For Something\n1. Text"
        formatted = formatted.replace(/\n(\d+)([A-Z])/g, '\n$1. $2');
        formatted = formatted.replace(/\n(\d+)([a-z])/g, '\n$1. $2');
        
        // Strip ALL HTML tags (with ANY attributes including style) to plain text/markdown
        let prevStrip = '';
        let maxIterations = 15;
        while (prevStrip !== formatted && maxIterations-- > 0) {
            prevStrip = formatted;
            formatted = formatted.replace(/<strong\b[^>]*>([\s\S]*?)<\/strong>/gi, '**$1**');
            formatted = formatted.replace(/<b\b[^>]*>([\s\S]*?)<\/b>/gi, '**$1**');
            formatted = formatted.replace(/<em\b[^>]*>([\s\S]*?)<\/em>/gi, '*$1*');
            formatted = formatted.replace(/<i\b[^>]*>([\s\S]*?)<\/i>/gi, '*$1*');
            formatted = formatted.replace(/<u\b[^>]*>([\s\S]*?)<\/u>/gi, '_$1_');
            formatted = formatted.replace(/<span\b[^>]*>([\s\S]*?)<\/span>/gi, '$1');
            formatted = formatted.replace(/<div\b[^>]*>([\s\S]*?)<\/div>/gi, '$1\n');
            formatted = formatted.replace(/<p\b[^>]*>([\s\S]*?)<\/p>/gi, '$1\n\n');
            formatted = formatted.replace(/<br\b[^>]*\/?>/gi, '\n');
            formatted = formatted.replace(/<h1\b[^>]*>([\s\S]*?)<\/h1>/gi, '# $1\n');
            formatted = formatted.replace(/<h2\b[^>]*>([\s\S]*?)<\/h2>/gi, '## $1\n');
            formatted = formatted.replace(/<h3\b[^>]*>([\s\S]*?)<\/h3>/gi, '### $1\n');
            formatted = formatted.replace(/<h4\b[^>]*>([\s\S]*?)<\/h4>/gi, '#### $1\n');
            formatted = formatted.replace(/<h5\b[^>]*>([\s\S]*?)<\/h5>/gi, '##### $1\n');
            formatted = formatted.replace(/<h6\b[^>]*>([\s\S]*?)<\/h6>/gi, '###### $1\n');
            formatted = formatted.replace(/<a\b[^>]*>([\s\S]*?)<\/a>/gi, '$1');
            formatted = formatted.replace(/<li\b[^>]*>([\s\S]*?)<\/li>/gi, '- $1\n');
            formatted = formatted.replace(/<\/?(?:ul|ol)\b[^>]*>/gi, '');
            formatted = formatted.replace(/<blockquote\b[^>]*>([\s\S]*?)<\/blockquote>/gi, '> $1\n');
            formatted = formatted.replace(/<code\b[^>]*>([\s\S]*?)<\/code>/gi, '`$1`');
            formatted = formatted.replace(/<pre\b[^>]*>([\s\S]*?)<\/pre>/gi, '```\n$1\n```');
            formatted = formatted.replace(/<hr\b[^>]*\/?>/gi, '\n---\n');
        }
        
        // Decode common HTML entities
        formatted = formatted.replace(/&amp;/g, '&');
        formatted = formatted.replace(/&lt;/g, '<');
        formatted = formatted.replace(/&gt;/g, '>');
        formatted = formatted.replace(/&quot;/g, '"');
        formatted = formatted.replace(/&#39;/g, "'");
        formatted = formatted.replace(/&#x27;/g, "'");
        formatted = formatted.replace(/&#039;/g, "'");
        formatted = formatted.replace(/&nbsp;/g, ' ');
        
        // After decoding entities, run HTML stripping again
        prevStrip = '';
        maxIterations = 5;
        while (prevStrip !== formatted && maxIterations-- > 0) {
            prevStrip = formatted;
            formatted = formatted.replace(/<strong\b[^>]*>([\s\S]*?)<\/strong>/gi, '**$1**');
            formatted = formatted.replace(/<b\b[^>]*>([\s\S]*?)<\/b>/gi, '**$1**');
            formatted = formatted.replace(/<em\b[^>]*>([\s\S]*?)<\/em>/gi, '*$1*');
            formatted = formatted.replace(/<i\b[^>]*>([\s\S]*?)<\/i>/gi, '*$1*');
            formatted = formatted.replace(/<span\b[^>]*>([\s\S]*?)<\/span>/gi, '$1');
        }
        
        // Clean up any remaining self-closing tags (but not our placeholders)
        formatted = formatted.replace(/<[a-z][^>]*\/>/gi, '');
        // Remove any remaining opening/closing tags that weren't caught (but preserve content)
        formatted = formatted.replace(/<\/?(?:font|center|marquee|blink|nobr|wbr|s|strike|del|ins|mark|small|big|sub|sup|abbr|acronym|cite|dfn|kbd|samp|var|tt)\b[^>]*>/gi, '');
        
        // Additional pass: Fix any remaining number-text spacing issues after HTML stripping
        // These patterns may have been hidden inside HTML tags - COMPREHENSIVE FIX
        // STEP 1: Fix numbered list items at start of lines
        formatted = formatted.replace(/^(\d+)([A-Z][a-zA-Z])/gm, '$1. $2');
        formatted = formatted.replace(/^(\d+)(\*\*[^*]+\*\*)/gm, '$1. $2');
        formatted = formatted.replace(/^(\d+)([a-zA-Z])/gm, '$1. $2');
        formatted = formatted.replace(/^(\d+)\.([^\s\d])/gm, '$1. $2');
        formatted = formatted.replace(/^(\d+)\)\s*/gm, '$1. ');
        formatted = formatted.replace(/^(\d+)-\s*/gm, '$1. ');
        // STEP 2: Fix numbers attached to words ANYWHERE in text
        formatted = formatted.replace(/(\s)(\d+)([A-Z][a-zA-Z])/g, '$1$2. $3');
        formatted = formatted.replace(/(\s)(\d+)([a-z])/g, '$1$2. $3');
        // STEP 3: Fix specific patterns like "Word1Word"
        formatted = formatted.replace(/([a-zA-Z])(\d+)([A-Z][a-zA-Z])/g, '$1\n$2. $3');
        formatted = formatted.replace(/([a-z])(\d+)([a-z])/g, '$1 $2. $3');
        // STEP 4: Fix bullet points without space
        formatted = formatted.replace(/^-([A-Za-z])/gm, '- $1');
        formatted = formatted.replace(/^\*([A-Za-z])/gm, '* $1');
        formatted = formatted.replace(/^•([A-Za-z])/gm, '• $1');
        // STEP 5: Fix after newlines
        formatted = formatted.replace(/\n(\d+)([A-Z])/g, '\n$1. $2');
        formatted = formatted.replace(/\n(\d+)([a-z])/g, '\n$1. $2');
        // STEP 6: Fix numbers inside bold markdown (e.g., **1Star** -> **1. Star**)
        formatted = formatted.replace(/\*\*(\d+)([A-Z][a-zA-Z])/g, '**$1. $2');
        formatted = formatted.replace(/\*\*(\d+)([a-z])/g, '**$1. $2');
        
        // Clean up multiple newlines and spaces
        formatted = formatted.replace(/\n{3,}/g, '\n\n');
        formatted = formatted.replace(/  +/g, ' ');
        
        // Store math blocks temporarily for PDF handling
        const mathBlocks = [];
        const inlineMathPdf = [];
        
        // Protect display math blocks: $$ ... $$ or \[ ... \]
        formatted = formatted.replace(/\$\$([\s\S]*?)\$\$/g, (_, math) => {
            const placeholder = `__PDF_MATH_BLOCK_${mathBlocks.length}__`;
            mathBlocks.push(math.trim());
            return placeholder;
        });
        formatted = formatted.replace(/\\\[([\s\S]*?)\\\]/g, (_, math) => {
            const placeholder = `__PDF_MATH_BLOCK_${mathBlocks.length}__`;
            mathBlocks.push(math.trim());
            return placeholder;
        });
        
        // Protect inline math: $ ... $ or \( ... \)
        formatted = formatted.replace(/(?<!\$)\$(?!\$)([^\$\n]+?)\$(?!\$)/g, (_, math) => {
            const placeholder = `__PDF_INLINE_MATH_${inlineMathPdf.length}__`;
            inlineMathPdf.push(math.trim());
            return placeholder;
        });
        formatted = formatted.replace(/\\\((.+?)\\\)/gs, (_, math) => {
            const placeholder = `__PDF_INLINE_MATH_${inlineMathPdf.length}__`;
            inlineMathPdf.push(math.trim());
            return placeholder;
        });
        
        // Store code blocks temporarily
        const codeBlocks = [];
        formatted = formatted.replace(/```(\w*)\n?([\s\S]*?)```/g, (_, lang, code) => {
            const placeholder = `__PDF_CODE_BLOCK_${codeBlocks.length}__`;
            const language = lang ? lang.toUpperCase() : 'CODE';
            codeBlocks.push(`<div class="code-block-wrapper"><div class="code-block-header">${this.escapeHtml(language)}</div><pre><code>${this.escapeHtml(code.trim())}</code></pre></div>`);
            return placeholder;
        });
        
        // Store inline codes
        const inlineCodes = [];
        formatted = formatted.replace(/`([^`]+)`/g, (_, code) => {
            const placeholder = `__PDF_INLINE_CODE_${inlineCodes.length}__`;
            inlineCodes.push(`<code style="background:#f1f5f9;padding:2px 6px;border-radius:4px;font-family:'Courier New',monospace;font-size:13px;color:#7c3aed;">${this.escapeHtml(code)}</code>`);
            return placeholder;
        });
        
        // Headings with PDF-optimized styling (use _formatInlineContentForPdf for inline formatting)
        formatted = formatted.replace(/^###### (.+)$/gm, (_, text) => `<h6 style="font-size:14px;font-weight:600;color:#4a5568;margin:16px 0 8px 0;">${this._formatInlineContentForPdf(text)}</h6>`);
        formatted = formatted.replace(/^##### (.+)$/gm, (_, text) => `<h5 style="font-size:15px;font-weight:600;color:#2d3748;margin:18px 0 10px 0;">${this._formatInlineContentForPdf(text)}</h5>`);
        formatted = formatted.replace(/^#### (.+)$/gm, (_, text) => `<h4 style="font-size:16px;font-weight:600;color:#2d3748;margin:20px 0 10px 0;">${this._formatInlineContentForPdf(text)}</h4>`);
        formatted = formatted.replace(/^### (.+)$/gm, (_, text) => `<h3 style="font-size:18px;font-weight:600;color:#667eea;margin:22px 0 12px 0;padding-left:12px;border-left:3px solid #667eea;">${this._formatInlineContentForPdf(text)}</h3>`);
        formatted = formatted.replace(/^## (.+)$/gm, (_, text) => `<h2 style="font-size:20px;font-weight:600;color:#1a202c;margin:24px 0 14px 0;padding-bottom:8px;border-bottom:1px solid #e2e8f0;">${this._formatInlineContentForPdf(text)}</h2>`);
        formatted = formatted.replace(/^# (.+)$/gm, (_, text) => `<h1 style="font-size:24px;font-weight:700;color:#667eea;margin:28px 0 16px 0;padding-bottom:10px;border-bottom:2px solid #667eea;">${this._formatInlineContentForPdf(text)}</h1>`);
        
        // Ordered lists with styled numbers (use _formatInlineContentForPdf for inline formatting)
        formatted = formatted.replace(/^(\d+)\.\s*(.+)$/gm, (_, num, text) => `<div style="display:flex;align-items:flex-start;margin:12px 0;gap:12px;"><span style="min-width:28px;height:28px;background:linear-gradient(135deg, #667eea 0%, #764ba2 100%);color:white;border-radius:50%;display:inline-flex;align-items:center;justify-content:center;font-size:12px;font-weight:600;flex-shrink:0;">${num}</span><span style="flex:1;line-height:1.7;padding-top:4px;">${this._formatInlineContentForPdf(text.trim())}</span></div>`);
        
        // Unordered lists with bullet points (use _formatInlineContentForPdf for inline formatting)
        formatted = formatted.replace(/^[-*•]\s*(.+)$/gm, (_, text) => `<div style="display:flex;align-items:flex-start;margin:10px 0;padding-left:4px;gap:12px;"><span style="color:#667eea;font-size:20px;line-height:1;flex-shrink:0;">•</span><span style="flex:1;line-height:1.7;">${this._formatInlineContentForPdf(text.trim())}</span></div>`);
        
        // Blockquotes (use _formatInlineContentForPdf for inline formatting)
        formatted = formatted.replace(/^> (.+)$/gm, (_, text) => `<blockquote style="margin:16px 0;padding:16px 20px;border-left:4px solid #667eea;background:linear-gradient(90deg, rgba(102, 126, 234, 0.08) 0%, transparent 100%);border-radius:0 8px 8px 0;font-style:italic;color:#4a5568;">${this._formatInlineContentForPdf(text)}</blockquote>`);
        
        // Tables for PDF
        formatted = this._parseMarkdownTablesForPdf(formatted);
        
        // Horizontal rules
        formatted = formatted.replace(/^---$/gm, '<hr style="border:none;height:2px;background:linear-gradient(90deg, transparent, #667eea, transparent);margin:24px 0;opacity:0.5;">');
        
        // Links (format link text for inline markdown)
        formatted = formatted.replace(/\[([^\]]+)\]\(([^)]+)\)/g, (_, text, url) => {
            const safeUrl = this._sanitizeUrl(url);
            if (!safeUrl) return this._formatInlineContentForPdf(text);
            return `<a href="${this.escapeHtml(safeUrl)}" style="color:#667eea;text-decoration:none;border-bottom:1px solid #667eea;">${this._formatInlineContentForPdf(text)}</a>`;
        });
        
        // Paragraphs - format inline content for any remaining markdown
        const lines = formatted.split('\n');
        const result = [];
        let paragraphContent = [];
        
        for (const line of lines) {
            const trimmed = line.trim();
            const isBlockElement = /^<(h[1-6]|div|blockquote|hr|pre|table|__PDF)/.test(trimmed) || 
                                   /<\/(h[1-6]|div|blockquote|pre|table)>$/.test(trimmed);
            
            if (isBlockElement || trimmed === '') {
                if (paragraphContent.length > 0) {
                    const formattedParagraph = paragraphContent.map(p => this._formatInlineContentForPdf(p)).join('<br>');
                    result.push('<p style="margin:0 0 12px 0;line-height:1.7;color:#2d3748;">' + formattedParagraph + '</p>');
                    paragraphContent = [];
                }
                if (trimmed !== '') result.push(line);
            } else {
                paragraphContent.push(trimmed);
            }
        }
        
        if (paragraphContent.length > 0) {
            const formattedParagraph = paragraphContent.map(p => this._formatInlineContentForPdf(p)).join('<br>');
            result.push('<p style="margin:0 0 12px 0;line-height:1.7;color:#2d3748;">' + formattedParagraph + '</p>');
        }
        
        formatted = result.join('\n');
        
        // Restore inline codes
        inlineCodes.forEach((code, i) => {
            formatted = formatted.replace(new RegExp(`__PDF_INLINE_CODE_${i}__`, 'g'), code);
        });
        
        // Restore code blocks
        codeBlocks.forEach((block, i) => {
            formatted = formatted.replace(new RegExp(`__PDF_CODE_BLOCK_${i}__`, 'g'), block);
        });
        
        // Restore math blocks with PDF-friendly rendering
        mathBlocks.forEach((math, i) => {
            const rendered = this._renderMathForPdf(math, true);
            formatted = formatted.replace(new RegExp(`__PDF_MATH_BLOCK_${i}__`, 'g'), rendered);
        });
        
        // Restore inline math
        inlineMathPdf.forEach((math, i) => {
            const rendered = this._renderMathForPdf(math, false);
            formatted = formatted.replace(new RegExp(`__PDF_INLINE_MATH_${i}__`, 'g'), rendered);
        });
        
        // Clean up
        formatted = formatted.replace(/<p[^>]*><br><\/p>/g, '');
        formatted = formatted.replace(/<p[^>]*>\s*<\/p>/g, '');
        
        return formatted;
    }

    // Render math for PDF with Unicode fallback (matches app.js _renderMathForPDF)
    _renderMathForPdf(math, displayMode = false) {
        if (!math) return '';
        
        // Convert LaTeX to Unicode for PDF
        let rendered = math
            // Handle \text{} - extract text content
            .replace(/\\text\{([^}]+)\}/g, (_, text) => text.replace(/_/g, ' '))
            .replace(/\\textit\{([^}]+)\}/g, '$1')
            .replace(/\\textbf\{([^}]+)\}/g, '$1')
            .replace(/\\mathrm\{([^}]+)\}/g, '$1')
            .replace(/\\mathit\{([^}]+)\}/g, '$1')
            .replace(/\\mathbf\{([^}]+)\}/g, '$1')
            // Remove sizing hints
            .replace(/\\left\s*/g, '').replace(/\\right\s*/g, '')
            .replace(/\\big\s*/g, '').replace(/\\Big\s*/g, '')
            .replace(/\\bigg\s*/g, '').replace(/\\Bigg\s*/g, '')
            // Fractions - handle nested ones
            .replace(/\\frac\{([^{}]*(?:\{[^{}]*\}[^{}]*)*)\}\{([^{}]*(?:\{[^{}]*\}[^{}]*)*)\}/g, '($1)/($2)')
            .replace(/\\frac\{([^}]+)\}\{([^}]+)\}/g, '($1/$2)')
            .replace(/\\dfrac\{([^}]+)\}\{([^}]+)\}/g, '($1/$2)')
            .replace(/\\tfrac\{([^}]+)\}\{([^}]+)\}/g, '($1/$2)')
            // Square roots
            .replace(/\\sqrt\[([^\]]+)\]\{([^}]+)\}/g, (_, n, x) => n === '3' ? `∛(${x})` : n === '4' ? `∜(${x})` : `${n}√(${x})`)
            .replace(/\\sqrt\{([^}]+)\}/g, '√($1)')
            .replace(/\\sqrt(\d+)/g, '√$1')
            // Integrals and sums
            .replace(/\\int_\{([^}]+)\}\^\{([^}]+)\}/g, '∫[$1→$2]')
            .replace(/\\int/g, '∫').replace(/\\oint/g, '∮')
            .replace(/\\sum_\{([^}]+)\}\^\{([^}]+)\}/g, 'Σ[$1→$2]')
            .replace(/\\sum/g, 'Σ').replace(/\\prod/g, '∏')
            .replace(/\\lim_\{([^}]+)\}/g, 'lim[$1]').replace(/\\lim/g, 'lim')
            // Calculus
            .replace(/\\partial/g, '∂').replace(/\\nabla/g, '∇').replace(/\\infty/g, '∞')
            // Greek letters (lowercase)
            .replace(/\\alpha/g, 'α').replace(/\\beta/g, 'β').replace(/\\gamma/g, 'γ')
            .replace(/\\delta/g, 'δ').replace(/\\epsilon/g, 'ε').replace(/\\varepsilon/g, 'ε')
            .replace(/\\zeta/g, 'ζ').replace(/\\eta/g, 'η').replace(/\\theta/g, 'θ')
            .replace(/\\iota/g, 'ι').replace(/\\kappa/g, 'κ').replace(/\\lambda/g, 'λ')
            .replace(/\\mu/g, 'μ').replace(/\\nu/g, 'ν').replace(/\\xi/g, 'ξ')
            .replace(/\\pi/g, 'π').replace(/\\rho/g, 'ρ').replace(/\\sigma/g, 'σ')
            .replace(/\\tau/g, 'τ').replace(/\\upsilon/g, 'υ').replace(/\\phi/g, 'φ')
            .replace(/\\chi/g, 'χ').replace(/\\psi/g, 'ψ').replace(/\\omega/g, 'ω')
            // Greek letters (uppercase)
            .replace(/\\Gamma/g, 'Γ').replace(/\\Delta/g, 'Δ').replace(/\\Theta/g, 'Θ')
            .replace(/\\Lambda/g, 'Λ').replace(/\\Xi/g, 'Ξ').replace(/\\Pi/g, 'Π')
            .replace(/\\Sigma/g, 'Σ').replace(/\\Phi/g, 'Φ').replace(/\\Psi/g, 'Ψ').replace(/\\Omega/g, 'Ω')
            // Math operators
            .replace(/\\times/g, '×').replace(/\\div/g, '÷').replace(/\\pm/g, '±')
            .replace(/\\mp/g, '∓').replace(/\\cdot/g, '·').replace(/\\ast/g, '∗')
            .replace(/\\star/g, '⋆').replace(/\\circ/g, '∘')
            // Comparisons
            .replace(/\\leq/g, '≤').replace(/\\geq/g, '≥').replace(/\\neq/g, '≠')
            .replace(/\\le/g, '≤').replace(/\\ge/g, '≥').replace(/\\ne/g, '≠')
            .replace(/\\approx/g, '≈').replace(/\\equiv/g, '≡').replace(/\\sim/g, '∼')
            .replace(/\\propto/g, '∝').replace(/\\ll/g, '≪').replace(/\\gg/g, '≫')
            // Arrows
            .replace(/\\rightarrow/g, '→').replace(/\\leftarrow/g, '←')
            .replace(/\\Rightarrow/g, '⇒').replace(/\\Leftarrow/g, '⇐')
            .replace(/\\leftrightarrow/g, '↔').replace(/\\Leftrightarrow/g, '⇔')
            .replace(/\\to/g, '→').replace(/\\gets/g, '←').replace(/\\mapsto/g, '↦')
            // Set theory
            .replace(/\\forall/g, '∀').replace(/\\exists/g, '∃')
            .replace(/\\in/g, '∈').replace(/\\notin/g, '∉')
            .replace(/\\subset/g, '⊂').replace(/\\supset/g, '⊃')
            .replace(/\\subseteq/g, '⊆').replace(/\\supseteq/g, '⊇')
            .replace(/\\cup/g, '∪').replace(/\\cap/g, '∩')
            .replace(/\\emptyset/g, '∅').replace(/\\varnothing/g, '∅')
            // Logic
            .replace(/\\land/g, '∧').replace(/\\lor/g, '∨').replace(/\\lnot/g, '¬').replace(/\\neg/g, '¬')
            // Misc
            .replace(/\\angle/g, '∠').replace(/\\triangle/g, '△')
            .replace(/\\perp/g, '⊥').replace(/\\parallel/g, '∥')
            .replace(/\\therefore/g, '∴').replace(/\\because/g, '∵')
            .replace(/\\ldots/g, '…').replace(/\\cdots/g, '⋯')
            .replace(/\\prime/g, '′').replace(/\\degree/g, '°')
            // Spacing
            .replace(/\\,/g, ' ').replace(/\\;/g, ' ').replace(/\\:/g, ' ')
            .replace(/\\!/g, '').replace(/\\quad/g, '  ').replace(/\\qquad/g, '    ')
            .replace(/\\ /g, ' ')
            // Remove remaining LaTeX commands but keep content in braces
            .replace(/\\[a-zA-Z]+\{([^}]*)\}/g, '$1')
            .replace(/\\[a-zA-Z]+/g, '')
            .replace(/\{([^{}]*)\}/g, '$1');
        
        // Handle superscripts and subscripts
        for (let i = 0; i < 5; i++) {
            rendered = rendered.replace(/\^(\{[^{}]+\})/g, (_, exp) => {
                const content = exp.slice(1, -1);
                return content.split('').map(c => SUPERSCRIPTS[c] || SUPERSCRIPTS[c.toLowerCase()] || c).join('');
            });
            rendered = rendered.replace(/\^([0-9a-zA-Z+\-])/g, (_, c) => {
                return SUPERSCRIPTS[c] || SUPERSCRIPTS[c.toLowerCase()] || `^${c}`;
            });
            rendered = rendered.replace(/_(\{[^{}]+\})/g, (_, exp) => {
                const content = exp.slice(1, -1);
                return content.split('').map(c => SUBSCRIPTS[c] || SUBSCRIPTS[c.toLowerCase()] || c).join('');
            });
            rendered = rendered.replace(/_([0-9a-zA-Z])/g, (_, c) => {
                return SUBSCRIPTS[c] || SUBSCRIPTS[c.toLowerCase()] || `_${c}`;
            });
        }
        
        // Final cleanup
        rendered = rendered.replace(/[{}]/g, '');
        
        if (displayMode) {
            return `<div style="margin:20px 0;padding:16px 20px;background:linear-gradient(135deg, rgba(102, 126, 234, 0.08) 0%, rgba(118, 75, 162, 0.08) 100%);border-radius:8px;border-left:4px solid #667eea;text-align:center;font-family:'Times New Roman',Georgia,serif;font-size:16px;font-style:italic;color:#2d3748;">${this.escapeHtml(rendered)}</div>`;
        }
        return `<span style="padding:2px 6px;background:rgba(102, 126, 234, 0.1);border-radius:4px;font-family:'Times New Roman',Georgia,serif;font-style:italic;">${this.escapeHtml(rendered)}</span>`;
    }

    _parseMarkdownTablesForPdf(content) {
        if (!content) return content;
        const lines = content.split('\n');
        const result = [];
        let i = 0;
        
        while (i < lines.length) {
            const line = lines[i];
            if (line.trim().startsWith('|') && line.trim().endsWith('|')) {
                const nextLine = lines[i + 1];
                if (nextLine && /^\|[\s:|-]+\|$/.test(nextLine.trim())) {
                    const tableLines = [line];
                    let j = i + 1;
                    while (j < lines.length && lines[j].trim().startsWith('|')) {
                        tableLines.push(lines[j]);
                        j++;
                    }
                    result.push(this._convertTableToHtmlForPdf(tableLines));
                    i = j;
                    continue;
                }
            }
            result.push(line);
            i++;
        }
        return result.join('\n');
    }

    _convertTableToHtmlForPdf(lines) {
        if (lines.length < 2) return lines.join('\n');
        
        const sep = lines[1];
        const aligns = sep.split('|').filter(c => c.trim()).map(c => {
            const t = c.trim();
            if (t.startsWith(':') && t.endsWith(':')) return 'center';
            if (t.endsWith(':')) return 'right';
            return 'left';
        });
        
        const headerCells = lines[0].split('|').filter(c => c.trim()).map(c => c.trim());
        let html = '<table style="width:100%;border-collapse:collapse;margin:20px 0;border-radius:12px;overflow:hidden;box-shadow:0 4px 12px rgba(0,0,0,0.1);"><thead><tr style="background:linear-gradient(135deg, #667eea 0%, #764ba2 100%);">';
        headerCells.forEach((h, i) => {
            html += `<th style="text-align:${aligns[i] || 'left'};padding:14px 16px;color:#ffffff;font-weight:600;font-size:12px;text-transform:uppercase;letter-spacing:0.5px;border:none;">${this._formatInlineContentForPdf(h)}</th>`;
        });
        html += '</tr></thead><tbody>';
        for (let i = 2; i < lines.length; i++) {
            const cells = lines[i].match(/\|([^|]*)/g)?.map(c => c.slice(1).trim()) || [];
            const rowBg = (i - 2) % 2 === 0 ? '#ffffff' : '#f8fafc';
            html += `<tr style="background:${rowBg};">`;
            cells.forEach((c, j) => {
                if (c !== undefined) {
                    html += `<td style="text-align:${aligns[j] || 'left'};padding:14px 16px;border-bottom:1px solid #e2e8f0;color:#2d3748;font-size:14px;">${this._formatInlineContentForPdf(c)}</td>`;
                }
            });
            html += '</tr>';
        }
        html += '</tbody></table>';
        return html;
    }

    // Format inline content for PDF (bold, italic, code, underline)
    _formatInlineContentForPdf(text) {
        if (!text) return '';
        let result = text;
        
        // Convert any escaped HTML tags back to markdown first
        result = result.replace(/&lt;strong[^&]*&gt;([\s\S]*?)&lt;\/strong&gt;/gi, '**$1**');
        result = result.replace(/&lt;b[^&]*&gt;([\s\S]*?)&lt;\/b&gt;/gi, '**$1**');
        result = result.replace(/&lt;em[^&]*&gt;([\s\S]*?)&lt;\/em&gt;/gi, '*$1*');
        result = result.replace(/&lt;i[^&]*&gt;([\s\S]*?)&lt;\/i&gt;/gi, '*$1*');
        result = result.replace(/&lt;u[^&]*&gt;([\s\S]*?)&lt;\/u&gt;/gi, '_$1_');
        result = result.replace(/&lt;code[^&]*&gt;([\s\S]*?)&lt;\/code&gt;/gi, '`$1`');
        
        // Convert raw HTML tags to markdown
        result = result.replace(/<strong[^>]*>([\s\S]*?)<\/strong>/gi, '**$1**');
        result = result.replace(/<b[^>]*>([\s\S]*?)<\/b>/gi, '**$1**');
        result = result.replace(/<em[^>]*>([\s\S]*?)<\/em>/gi, '*$1*');
        result = result.replace(/<i[^>]*>([\s\S]*?)<\/i>/gi, '*$1*');
        result = result.replace(/<u[^>]*>([\s\S]*?)<\/u>/gi, '_$1_');
        result = result.replace(/<code[^>]*>([\s\S]*?)<\/code>/gi, '`$1`');
        result = result.replace(/<span[^>]*>([\s\S]*?)<\/span>/gi, '$1');
        
        // Store formatted content with markers
        const bolds = [];
        const italics = [];
        const underlines = [];
        const codes = [];
        const boldMarker = '\u0000BOLD\u0000';
        const italicMarker = '\u0000ITALIC\u0000';
        const underlineMarker = '\u0000UNDERLINE\u0000';
        const codeMarker = '\u0000CODE\u0000';
        
        // Extract bold **text**
        result = result.replace(/\*\*([^*]+)\*\*/g, (_, content) => {
            bolds.push(content);
            return `${boldMarker}${bolds.length - 1}${boldMarker}`;
        });
        
        // Extract italic *text*
        result = result.replace(/(?<!\*)\*([^*]+)\*(?!\*)/g, (_, content) => {
            italics.push(content);
            return `${italicMarker}${italics.length - 1}${italicMarker}`;
        });
        
        // Extract underline _text_
        result = result.replace(/(?<![_\w])_([^_]+)_(?![_\w])/g, (match, content) => {
            if (/__/.test(match)) return match;
            underlines.push(content);
            return `${underlineMarker}${underlines.length - 1}${underlineMarker}`;
        });
        
        // Extract inline code `code`
        result = result.replace(/`([^`]+)`/g, (_, content) => {
            codes.push(content);
            return `${codeMarker}${codes.length - 1}${codeMarker}`;
        });
        
        // Escape HTML for XSS protection
        result = this.escapeHtmlDisplay(result);
        
        // Restore bold with styled HTML for PDF
        bolds.forEach((content, i) => {
            result = result.replace(new RegExp(`${boldMarker}${i}${boldMarker}`, 'g'), 
                `<strong style="font-weight:600;color:#1a202c;">${this.escapeHtmlDisplay(content)}</strong>`);
        });
        
        // Restore italic with styled HTML for PDF
        italics.forEach((content, i) => {
            result = result.replace(new RegExp(`${italicMarker}${i}${italicMarker}`, 'g'), 
                `<em style="font-style:italic;color:#4a5568;">${this.escapeHtmlDisplay(content)}</em>`);
        });
        
        // Restore underline with styled HTML for PDF
        underlines.forEach((content, i) => {
            result = result.replace(new RegExp(`${underlineMarker}${i}${underlineMarker}`, 'g'), 
                `<u style="text-decoration:underline;">${this.escapeHtmlDisplay(content)}</u>`);
        });
        
        // Restore inline code with styled HTML for PDF
        codes.forEach((content, i) => {
            result = result.replace(new RegExp(`${codeMarker}${i}${codeMarker}`, 'g'), 
                `<code style="background:#f1f5f9;padding:2px 6px;border-radius:4px;font-family:'Fira Code',monospace;font-size:12px;color:#e53e3e;">${this.escapeHtmlDisplay(content)}</code>`);
        });
        
        return result;
    }

    // Generate PDF HTML template (same professional styling as main app.js)
    _getPdfTemplate(title, dateStr, timeStr, content, isChat = false) {
        return `<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>${this.escapeHtml(title)}</title>
    <link href="https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&family=Fira+Code:wght@400;500&display=swap" rel="stylesheet">
    <style>
        * { margin: 0; padding: 0; box-sizing: border-box; }
        @page { margin: 0.5in; size: A4; }
        @media print {
            * { -webkit-print-color-adjust: exact !important; print-color-adjust: exact !important; }
            body { padding: 0.5in; }
            .code-header { background: linear-gradient(135deg, #667eea 0%, #764ba2 100%) !important; }
        }
        body {
            font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            font-size: 14px; line-height: 1.7; color: #1a1a2e; background: #fff;
            padding: 40px; max-width: 800px; margin: 0 auto;
        }
        .pdf-header {
            display: flex; align-items: center; justify-content: space-between;
            padding-bottom: 24px; margin-bottom: 32px; border-bottom: 2px solid #e5e7eb;
        }
        .pdf-brand { display: flex; align-items: center; gap: 16px; }
        .pdf-logo { width: 64px; height: 64px; shape-rendering: geometricPrecision; image-rendering: -webkit-optimize-contrast; image-rendering: crisp-edges; }
        .pdf-title {
            font-size: 28px; font-weight: 700;
            color: #667eea;
            text-rendering: optimizeLegibility;
            -webkit-font-smoothing: antialiased;
            letter-spacing: -0.5px;
        }
        .pdf-meta { text-align: right; color: #6b7280; font-size: 12px; }
        .pdf-meta-date { font-weight: 600; color: #374151; margin-bottom: 4px; }
        .pdf-meta-label {
            display: inline-block; padding: 4px 10px;
            background: #667eea;
            color: white; border-radius: 12px; font-size: 10px; font-weight: 600;
            text-transform: uppercase; letter-spacing: 0.5px; margin-top: 8px;
        }
        .pdf-content { padding: 24px 0; }
        .summary { font-size: 14px; color: #6b7280; margin-bottom: 20px; }
        .summary strong { color: #667eea; }
        
        /* Stats Grid */
        .stats-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin-bottom: 32px; }
        .stat-card {
            background: linear-gradient(135deg, #f8fafc 0%, #f1f5f9 100%);
            border: 1px solid #e5e7eb; border-radius: 12px; padding: 20px; text-align: center;
        }
        .stat-value { font-size: 28px; font-weight: 700; color: #667eea; }
        .stat-label { font-size: 12px; color: #6b7280; margin-top: 4px; }
        
        /* Model Usage */
        .model-usage { margin-top: 16px; }
        .usage-row { display: flex; align-items: center; gap: 12px; margin-bottom: 12px; }
        .usage-label { width: 120px; font-size: 13px; color: #374151; font-weight: 500; }
        .usage-bar { flex: 1; height: 8px; background: #e5e7eb; border-radius: 4px; overflow: hidden; }
        .usage-fill { height: 100%; background: linear-gradient(135deg, #667eea 0%, #764ba2 100%); border-radius: 4px; }
        .usage-value { width: 80px; font-size: 12px; color: #6b7280; text-align: right; }
        
        /* Tables */
        table { width: 100%; border-collapse: collapse; margin: 20px 0; font-size: 13px; border-radius: 8px; overflow: hidden; box-shadow: 0 2px 8px rgba(0,0,0,0.08); }
        th, td { padding: 12px 16px; text-align: left; border-bottom: 1px solid #e5e7eb; }
        th { background: linear-gradient(135deg, #667eea 0%, #764ba2 100%); color: white; font-weight: 600; }
        tr:nth-child(even) { background: #f9fafb; }
        tr:last-child td { border-bottom: none; }
        .status-badge { padding: 4px 8px; border-radius: 12px; font-size: 11px; font-weight: 500; }
        .status-badge.online { background: #d1fae5; color: #059669; }
        
        /* Messages */
        .messages { display: flex; flex-direction: column; gap: 24px; }
        .message { border-radius: 12px; overflow: hidden; }
        .message.user { background: #f8fafc; border: 1px solid #e5e7eb; }
        .message.assistant { background: linear-gradient(135deg, rgba(102,126,234,0.05) 0%, rgba(118,75,162,0.05) 100%); border: 1px solid rgba(102,126,234,0.2); }
        .message-header { display: flex; align-items: center; justify-content: space-between; padding: 12px 16px; border-bottom: 1px solid rgba(0,0,0,0.05); }
        .role-badge { padding: 4px 12px; border-radius: 12px; font-size: 11px; font-weight: 600; text-transform: uppercase; }
        .user-badge { background: #374151; color: white; }
        .ai-badge { background: linear-gradient(135deg, #667eea 0%, #764ba2 100%); color: white; }
        .message-meta { font-size: 11px; color: #9ca3af; }
        .message-content { padding: 16px; line-height: 1.7; color: #374151; }
        .message-content p { margin: 0 0 12px; }
        .message-content p:last-child { margin-bottom: 0; }
        
        /* Headings */
        h1 { font-size: 22px; font-weight: 700; color: #667eea; margin: 24px 0 12px; padding-bottom: 8px; border-bottom: 2px solid #667eea; }
        h2 { font-size: 18px; font-weight: 600; color: #1f2937; margin: 20px 0 10px; padding-bottom: 6px; border-bottom: 1px solid #e5e7eb; }
        h3 { font-size: 16px; font-weight: 600; color: #667eea; margin: 16px 0 8px; padding-left: 10px; border-left: 3px solid #667eea; }
        h4, h5, h6 { font-size: 14px; font-weight: 600; color: #374151; margin: 14px 0 6px; }
        
        /* Lists */
        ul, ol { margin: 12px 0; padding-left: 24px; }
        li { margin: 6px 0; color: #374151; }
        li::marker { color: #667eea; }
        
        /* Code */
        .code-block { margin: 16px 0; border-radius: 8px; overflow: hidden; box-shadow: 0 2px 8px rgba(0,0,0,0.1); }
        .code-block-wrapper { margin: 16px 0; border-radius: 8px; overflow: hidden; box-shadow: 0 4px 12px rgba(0,0,0,0.1); }
        .code-header, .code-block-header { background: linear-gradient(135deg, #667eea 0%, #764ba2 100%); color: white; padding: 8px 16px; font-size: 11px; font-weight: 600; letter-spacing: 0.5px; }
        .code-block pre, .code-block-wrapper pre { margin: 0; background: #1e293b; }
        .code-block code, .code-block-wrapper code { display: block; padding: 16px; font-family: 'Fira Code', monospace; font-size: 13px; line-height: 1.6; color: #e2e8f0; white-space: pre-wrap; word-wrap: break-word; }
        .inline-code { background: #f3e8ff; color: #7c3aed; padding: 2px 6px; border-radius: 4px; font-family: 'Fira Code', monospace; font-size: 13px; }
        
        /* Blockquotes */
        blockquote { margin: 16px 0; padding: 12px 20px; border-left: 4px solid #667eea; background: #f8fafc; border-radius: 0 8px 8px 0; color: #4b5563; font-style: italic; }
        
        /* Links */
        a { color: #667eea; text-decoration: none; border-bottom: 1px solid #667eea; }
        
        /* HR */
        hr { border: none; height: 2px; background: linear-gradient(90deg, #667eea 0%, #764ba2 50%, #667eea 100%); margin: 24px 0; }
        
        strong { font-weight: 600; color: #1f2937; }
        em { font-style: italic; color: #4b5563; }
        
        /* Footer */
        .pdf-footer { margin-top: 40px; padding-top: 20px; border-top: 2px solid #e5e7eb; text-align: center; color: #9ca3af; font-size: 12px; text-rendering: optimizeLegibility; }
        .pdf-footer-brand { display: inline-flex; align-items: center; gap: 8px; font-weight: 600; color: #6b7280; -webkit-font-smoothing: antialiased; }
        .pdf-footer-logo { width: 28px; height: 28px; shape-rendering: geometricPrecision; image-rendering: crisp-edges; }
        
        @media print {
            .message { page-break-inside: avoid; }
            .code-block { page-break-inside: avoid; }
            h1, h2, h3, h4, h5, h6 { page-break-after: avoid; }
        }
    </style>
</head>
<body>
    <header class="pdf-header">
        <div class="pdf-brand">
            <svg class="pdf-logo" viewBox="0 0 64 64" xmlns="http://www.w3.org/2000/svg" shape-rendering="geometricPrecision" text-rendering="geometricPrecision">
                <path d="M32 8 L56 20 L56 44 L32 56 L8 44 L8 20 Z" stroke="#667eea" stroke-width="4" fill="none" stroke-linejoin="round"/>
                <circle cx="32" cy="32" r="12" fill="#764ba2"/>
            </svg>
            <span class="pdf-title">${this.escapeHtml(title)}</span>
        </div>
        <div class="pdf-meta">
            <div class="pdf-meta-date">${dateStr} at ${timeStr}</div>
            <span class="pdf-meta-label">Admin Report</span>
        </div>
    </header>
    <main class="pdf-content">${content}</main>
    <footer class="pdf-footer">
        <div class="pdf-footer-brand">
            <svg class="pdf-footer-logo" viewBox="0 0 64 64" xmlns="http://www.w3.org/2000/svg" shape-rendering="geometricPrecision" text-rendering="geometricPrecision"><path d="M32 8 L56 20 L56 44 L32 56 L8 44 L8 20 Z" stroke="#667eea" stroke-width="4" fill="none" stroke-linejoin="round"/><circle cx="32" cy="32" r="10" fill="#764ba2"/></svg>
            Generated by Rox AI Admin Panel
        </div>
    </footer>
</body>
</html>`;
    }

    // Print PDF using browser print dialog (same approach as main app.js)
    _printPdf(pdfHtml) {
        let existingFrame = document.getElementById('adminPdfFrame');
        if (existingFrame) existingFrame.remove();
        
        const printFrame = document.createElement('iframe');
        printFrame.id = 'adminPdfFrame';
        printFrame.style.cssText = 'position:fixed;right:0;bottom:0;width:0;height:0;border:0;';
        document.body.appendChild(printFrame);
        
        const frameWindow = printFrame.contentWindow;
        if (!frameWindow) {
            this._showToast('Failed to create print frame', 'error');
            return;
        }
        
        const doc = frameWindow.document;
        doc.open();
        doc.write(pdfHtml);
        doc.close();
        
        setTimeout(() => {
            try {
                frameWindow.focus();
                frameWindow.print();
            } catch (e) {
                const printWindow = window.open('', '_blank', 'width=800,height=600');
                if (printWindow) {
                    printWindow.document.write(pdfHtml);
                    printWindow.document.close();
                    printWindow.focus();
                    setTimeout(() => printWindow.print(), 300);
                }
            }
        }, 500);
    }

    // Store current messages for export
    _currentMessages = [];

    // ==================== USER DETAILS PANEL ====================
    _renderUserDetailsPanel(user) {
        if (!this.userDetailsContent || !user) return;
        
        const isOnline = user.isOnline;
        const firstSeenDate = user.firstSeen ? new Date(user.firstSeen).toLocaleDateString() : 'Unknown';
        const lastActiveDate = user.lastActivity ? new Date(user.lastActivity).toLocaleString() : 'Unknown';
        const engagementScore = user.engagementScore || 0;
        const userType = user.userType || 'New';
        
        // Generate avatar initials from IP
        const ipParts = user.ip.split('.');
        const avatarText = ipParts.length >= 2 ? ipParts[0].slice(-1) + ipParts[1].slice(-1) : 'U';
        
        // Build activity chart
        let activityChartHtml = '';
        if (user.activityByHour && user.activityByHour.some(v => v > 0)) {
            const maxActivity = Math.max(...user.activityByHour, 1);
            activityChartHtml = `
                <div class="user-activity-timeline">
                    <div class="activity-hour-bar">
                        ${user.activityByHour.map((val, hour) => {
                            const height = Math.max((val / maxActivity) * 100, 5);
                            const isPeak = val === maxActivity && val > 0;
                            return `<div class="activity-hour ${isPeak ? 'peak' : ''}" style="height: ${height}%" title="${hour}:00 - ${val} actions"></div>`;
                        }).join('')}
                    </div>
                    <div class="activity-hour-labels">
                        <span>12AM</span>
                        <span>6AM</span>
                        <span>12PM</span>
                        <span>6PM</span>
                        <span>11PM</span>
                    </div>
                </div>
            `;
        }
        
        // Build user tags
        const tags = [];
        if (user.sessionCount <= 1) tags.push({ label: 'New User', class: 'new' });
        else if (user.sessionCount > 5) tags.push({ label: 'Power User', class: 'power' });
        else tags.push({ label: 'Returning', class: 'returning' });
        
        if (user.bounceStatus === 'Bounced') tags.push({ label: 'Bounced', class: 'dormant' });
        if (user.totalTokensUsed > 10000) tags.push({ label: 'Heavy Usage', class: 'power' });
        if (user.errorCount > 0) tags.push({ label: `${user.errorCount} Errors`, class: 'dormant' });
        
        const tagsHtml = tags.map(t => `<span class="user-tag ${t.class}">${t.label}</span>`).join('');
        
        const html = `
            <!-- User Profile Card -->
            <div class="user-profile-card">
                <div class="user-profile-header">
                    <div class="user-profile-avatar">${avatarText.toUpperCase()}</div>
                    <div class="user-profile-info">
                        <div class="user-profile-ip">${this.escapeHtml(user.ip)}</div>
                        <div class="user-profile-status">
                            <span class="status-dot ${isOnline ? 'online' : ''}"></span>
                            <span>${isOnline ? 'Online now' : 'Offline'}</span>
                        </div>
                    </div>
                </div>
                
                <!-- User Stats Grid -->
                <div class="user-stats-grid">
                    <div class="user-stat-item">
                        <div class="user-stat-value">${user.chatCount || 0}</div>
                        <div class="user-stat-label">Chats</div>
                    </div>
                    <div class="user-stat-item">
                        <div class="user-stat-value">${user.totalMessages || 0}</div>
                        <div class="user-stat-label">Messages</div>
                    </div>
                    <div class="user-stat-item">
                        <div class="user-stat-value">${user.sessionCount || 1}</div>
                        <div class="user-stat-label">Sessions</div>
                    </div>
                    <div class="user-stat-item">
                        <div class="user-stat-value">${engagementScore}%</div>
                        <div class="user-stat-label">Engagement</div>
                    </div>
                </div>
                
                <!-- User Tags -->
                <div class="user-tags">${tagsHtml}</div>
            </div>
            
            <!-- Device Info Section -->
            <div class="user-info-section">
                <div class="user-info-section-title">
                    <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
                        <rect x="2" y="3" width="20" height="14" rx="2" ry="2"/><line x1="8" y1="21" x2="16" y2="21"/><line x1="12" y1="17" x2="12" y2="21"/>
                    </svg>
                    Device Info
                </div>
                <div class="user-info-row">
                    <span class="user-info-label">Browser</span>
                    <span class="user-info-value">${this.escapeHtml(user.device?.fullBrowser || user.device?.browser || 'Unknown')}</span>
                </div>
                <div class="user-info-row">
                    <span class="user-info-label">OS</span>
                    <span class="user-info-value">${this.escapeHtml(user.device?.fullOs || user.device?.os || 'Unknown')}</span>
                </div>
                <div class="user-info-row">
                    <span class="user-info-label">Device Type</span>
                    <span class="user-info-value">${this.escapeHtml(user.device?.device || 'Unknown')}</span>
                </div>
                ${user.screenResolution ? `
                <div class="user-info-row">
                    <span class="user-info-label">Screen</span>
                    <span class="user-info-value">${this.escapeHtml(user.screenResolution)}</span>
                </div>
                ` : ''}
                ${user.colorScheme ? `
                <div class="user-info-row">
                    <span class="user-info-label">Theme</span>
                    <span class="user-info-value">${user.colorScheme === 'dark' ? '🌙 Dark' : '☀️ Light'}</span>
                </div>
                ` : ''}
                ${user.connectionType ? `
                <div class="user-info-row">
                    <span class="user-info-label">Connection</span>
                    <span class="user-info-value">${this.escapeHtml(user.connectionType)}</span>
                </div>
                ` : ''}
            </div>
            
            <!-- Location Info Section -->
            <div class="user-info-section">
                <div class="user-info-section-title">
                    <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
                        <path d="M21 10c0 7-9 13-9 13s-9-6-9-13a9 9 0 0118 0z"/><circle cx="12" cy="10" r="3"/>
                    </svg>
                    Location & Source
                </div>
                ${user.country ? `
                <div class="user-info-row">
                    <span class="user-info-label">Country</span>
                    <span class="user-info-value">${this.escapeHtml(user.country)}</span>
                </div>
                ` : ''}
                ${user.city ? `
                <div class="user-info-row">
                    <span class="user-info-label">City</span>
                    <span class="user-info-value">${this.escapeHtml(user.city)}</span>
                </div>
                ` : ''}
                ${user.language && user.language !== 'Unknown' ? `
                <div class="user-info-row">
                    <span class="user-info-label">Language</span>
                    <span class="user-info-value">${this.escapeHtml(user.language)}</span>
                </div>
                ` : ''}
                ${user.referer && user.referer !== 'Direct' ? `
                <div class="user-info-row">
                    <span class="user-info-label">Source</span>
                    <span class="user-info-value">${this.escapeHtml(user.referer)}</span>
                </div>
                ` : `
                <div class="user-info-row">
                    <span class="user-info-label">Source</span>
                    <span class="user-info-value">Direct</span>
                </div>
                `}
            </div>
            
            <!-- Activity Info Section -->
            <div class="user-info-section">
                <div class="user-info-section-title">
                    <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
                        <polyline points="22 12 18 12 15 21 9 3 6 12 2 12"/>
                    </svg>
                    Activity
                </div>
                <div class="user-info-row">
                    <span class="user-info-label">First Seen</span>
                    <span class="user-info-value">${firstSeenDate}</span>
                </div>
                <div class="user-info-row">
                    <span class="user-info-label">Last Active</span>
                    <span class="user-info-value">${lastActiveDate}</span>
                </div>
                ${user.visits ? `
                <div class="user-info-row">
                    <span class="user-info-label">Visits</span>
                    <span class="user-info-value">${user.visits}</span>
                </div>
                ` : ''}
                ${user.pageViews ? `
                <div class="user-info-row">
                    <span class="user-info-label">Page Views</span>
                    <span class="user-info-value">${user.pageViews}</span>
                </div>
                ` : ''}
                ${user.totalSessionTime ? `
                <div class="user-info-row">
                    <span class="user-info-label">Total Time</span>
                    <span class="user-info-value">${user.totalSessionTime}m</span>
                </div>
                ` : ''}
                ${user.peakActivityHour !== null && user.peakActivityHour !== undefined ? `
                <div class="user-info-row">
                    <span class="user-info-label">Peak Hour</span>
                    <span class="user-info-value highlight">${user.peakActivityHour}:00</span>
                </div>
                ` : ''}
                ${activityChartHtml}
            </div>
            
            <!-- Model Usage Section -->
            ${user.favoriteModel || user.totalTokensUsed ? `
            <div class="user-info-section">
                <div class="user-info-section-title">
                    <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
                        <path d="M12 2L2 7l10 5 10-5-10-5z"/><path d="M2 17l10 5 10-5"/><path d="M2 12l10 5 10-5"/>
                    </svg>
                    AI Usage
                </div>
                ${user.favoriteModel ? `
                <div class="user-info-row">
                    <span class="user-info-label">Favorite Model</span>
                    <span class="user-info-value highlight">${this.escapeHtml(user.favoriteModel)}</span>
                </div>
                ` : ''}
                ${user.totalTokensUsed ? `
                <div class="user-info-row">
                    <span class="user-info-label">Tokens Used</span>
                    <span class="user-info-value">${this._formatNumber(user.totalTokensUsed)}</span>
                </div>
                ` : ''}
                ${user.avgResponseTime ? `
                <div class="user-info-row">
                    <span class="user-info-label">Avg Response</span>
                    <span class="user-info-value">${user.avgResponseTime}ms</span>
                </div>
                ` : ''}
                ${user.errorCount > 0 ? `
                <div class="user-info-row">
                    <span class="user-info-label">Errors</span>
                    <span class="user-info-value error">${user.errorCount}</span>
                </div>
                ` : ''}
            </div>
            ` : ''}
            
            <!-- Privacy Section -->
            ${user.doNotTrack ? `
            <div class="user-info-section">
                <div class="user-info-section-title">
                    <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
                        <path d="M12 22s8-4 8-10V5l-8-3-8 3v7c0 6 8 10 8 10z"/>
                    </svg>
                    Privacy
                </div>
                <div class="user-info-row">
                    <span class="user-info-label">Do Not Track</span>
                    <span class="user-info-value warning">Enabled</span>
                </div>
            </div>
            ` : ''}
        `;
        
        this.userDetailsContent.innerHTML = html;
        
        // Show the panel
        if (this.userDetailsPanel) {
            this.userDetailsPanel.classList.add('active');
        }
    }
    
    _hideUserDetails() {
        if (this.userDetailsPanel) {
            this.userDetailsPanel.classList.remove('active');
        }
        if (this.userDetailsContent) {
            this.userDetailsContent.innerHTML = `
                <div class="empty-state">
                    <svg width="48" height="48" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.5">
                        <path d="M20 21v-2a4 4 0 0 0-4-4H8a4 4 0 0 0-4 4v2"/><circle cx="12" cy="7" r="4"/>
                    </svg>
                    <p>Select a user to view details</p>
                </div>
            `;
        }
    }

    _confirmClearLogs() {
        this._showDialog({
            title: 'Clear All Logs',
            message: 'This will permanently delete all chat logs and user data. This action cannot be undone.',
            type: 'danger',
            onConfirm: () => this._clearLogs()
        });
    }

    async _clearLogs() {
        try {
            const res = await this._apiPost('/clear-logs', { confirm: true });
            if (res.success) {
                this._showToast(`Cleared ${res.cleared} logs`, 'success');
                this._loadData();
                this.currentUser = null;
                this.currentChat = null;
                this.selectedUserName.textContent = '-';
                this.chatsList.innerHTML = '<div class="empty-state"><p>Select a user to view chats</p></div>';
                this.messagesArea.innerHTML = '<div class="empty-state"><p>Select a chat to view messages</p></div>';
                this.chatHeader.style.display = 'none';
            } else {
                this._showToast(res.error || 'Clear failed', 'error');
            }
        } catch (err) {
            this._showToast('Clear failed', 'error');
        }
    }

    // ==================== UI HELPERS ====================
    _showDialog({ title, message, type = 'warning', onConfirm }) {
        this.dialogTitle.textContent = title;
        this.dialogMessage.textContent = message;
        
        const icon = document.getElementById('dialogIcon');
        icon.className = `dialog-icon ${type}`;
        icon.innerHTML = type === 'danger' 
            ? '<svg width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><path d="M3 6h18M19 6v14a2 2 0 01-2 2H7a2 2 0 01-2-2V6m3 0V4a2 2 0 012-2h4a2 2 0 012 2v2"/></svg>'
            : '<svg width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><path d="M10.29 3.86L1.82 18a2 2 0 001.71 3h16.94a2 2 0 001.71-3L13.71 3.86a2 2 0 00-3.42 0z"/><line x1="12" y1="9" x2="12" y2="13"/><line x1="12" y1="17" x2="12.01" y2="17"/></svg>';
        
        this.dialogConfirm.onclick = () => {
            this._hideDialog();
            if (onConfirm) onConfirm();
        };
        
        this.dialogOverlay.style.display = 'flex';
    }

    _hideDialog() {
        this.dialogOverlay.style.display = 'none';
    }
    
    _showHelp() {
        this.helpOverlay.style.display = 'flex';
    }
    
    _hideHelp() {
        this.helpOverlay.style.display = 'none';
    }

    _showToast(message, type = 'info', duration = 5000) {
        const toast = document.createElement('div');
        toast.className = `toast ${type}`;
        
        const icons = {
            success: '<svg width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><path d="M22 11.08V12a10 10 0 11-5.93-9.14"/><polyline points="22 4 12 14.01 9 11.01"/></svg>',
            error: '<svg width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><circle cx="12" cy="12" r="10"/><line x1="15" y1="9" x2="9" y2="15"/><line x1="9" y1="9" x2="15" y2="15"/></svg>',
            warning: '<svg width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><path d="M10.29 3.86L1.82 18a2 2 0 001.71 3h16.94a2 2 0 001.71-3L13.71 3.86a2 2 0 00-3.42 0z"/><line x1="12" y1="9" x2="12" y2="13"/><line x1="12" y1="17" x2="12.01" y2="17"/></svg>',
            info: '<svg width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><circle cx="12" cy="12" r="10"/><path d="M12 16v-4M12 8h.01"/></svg>'
        };
        
        toast.innerHTML = `
            <span class="toast-icon">${icons[type] || icons.info}</span>
            <span class="toast-message">${this.escapeHtml(message)}</span>
            <button class="toast-close" aria-label="Close notification">×</button>
        `;
        
        const closeBtn = toast.querySelector('.toast-close');
        closeBtn.onclick = () => this._removeToast(toast);
        
        this.toastContainer.appendChild(toast);
        
        // Auto-remove with enhanced animation
        const timeoutId = setTimeout(() => this._removeToast(toast), duration);
        
        // Pause auto-remove on hover
        toast.addEventListener('mouseenter', () => clearTimeout(timeoutId));
        toast.addEventListener('mouseleave', () => {
            setTimeout(() => this._removeToast(toast), 1000);
        });
        
        // Add progress bar for visual feedback
        if (duration > 2000) {
            const progressBar = document.createElement('div');
            progressBar.className = 'toast-progress';
            progressBar.style.cssText = `
                position: absolute;
                bottom: 0;
                left: 0;
                height: 2px;
                background: currentColor;
                opacity: 0.3;
                animation: toast-progress ${duration}ms linear;
            `;
            toast.appendChild(progressBar);
        }
    }
    
    _removeToast(toast) {
        if (toast && toast.parentNode) {
            toast.classList.add('removing');
            setTimeout(() => {
                if (toast.parentNode) {
                    toast.parentNode.removeChild(toast);
                }
            }, 300);
        }
    }

    // ==================== UTILITY FUNCTIONS ====================
    escapeHtml(str) {
        if (!str || typeof str !== 'string') return '';
        return str.replace(/[&<>"']/g, c => HTML_ESCAPE_MAP[c] || c);
    }

    // Display-safe escape - only escapes < and > for XSS, preserves & and quotes for readability
    escapeHtmlDisplay(text) {
        if (typeof text !== 'string') return '';
        return text.replace(/</g, '&lt;').replace(/>/g, '&gt;');
    }

    // Auto-format math expressions (superscripts, subscripts, symbols)
    _autoFormatMathExpressions(content) {
        if (!content || typeof content !== 'string') return content;
        
        let formatted = content;
        
        // Convert superscript patterns: x^2, r^6, n^{10}, etc.
        formatted = formatted.replace(/\b([a-zA-Z])\^(\{([^}]+)\}|([0-9]+))\b/g, (match, base, _, bracedExp, plainExp) => {
            const exp = bracedExp || plainExp;
            const converted = exp.split('').map(c => SUPERSCRIPTS[c] || SUPERSCRIPTS[c.toLowerCase()] || c).join('');
            const allConverted = exp.split('').every(c => SUPERSCRIPTS[c] || SUPERSCRIPTS[c.toLowerCase()]);
            if (allConverted) return base + converted;
            return match;
        });
        
        // Convert subscript patterns: x_1, a_n, x_{10}, etc.
        formatted = formatted.replace(/\b([a-zA-Z])_(\{([^}]+)\}|([0-9]))\b/g, (match, base, _, bracedSub, plainSub) => {
            if (match.includes('__')) return match;
            const sub = bracedSub || plainSub;
            const converted = sub.split('').map(c => SUBSCRIPTS[c] || SUBSCRIPTS[c.toLowerCase()] || c).join('');
            const allConverted = sub.split('').every(c => SUBSCRIPTS[c] || SUBSCRIPTS[c.toLowerCase()]);
            if (allConverted) return base + converted;
            return match;
        });
        
        // Convert scientific notation: 1e6 → 1×10⁶
        formatted = formatted.replace(/\b(\d+\.?\d*)[eE]([+-]?\d+)\b/g, (_, num, exp) => {
            const expConverted = exp.split('').map(c => SUPERSCRIPTS[c] || c).join('');
            return `${num}×10${expConverted}`;
        });
        
        // Style common math symbols
        const mathSymbols = [
            '≈', '≠', '≤', '≥', '±', '∓', '×', '÷', '·',
            '→', '←', '↔', '⇒', '⇐', '⇔', '↑', '↓',
            '∞', '∝', '∂', '∇', '∫', '∑', '∏',
            '∈', '∉', '⊂', '⊃', '⊆', '⊇', '∪', '∩', '∅',
            '∀', '∃', '∧', '∨', '¬',
            'α', 'β', 'γ', 'δ', 'ε', 'ζ', 'η', 'θ',
            'ι', 'κ', 'λ', 'μ', 'ν', 'ξ', 'π', 'ρ',
            'σ', 'τ', 'υ', 'φ', 'χ', 'ψ', 'ω',
            'Γ', 'Δ', 'Θ', 'Λ', 'Ξ', 'Π', 'Σ', 'Φ', 'Ψ', 'Ω',
            '√', '∛', '∜'
        ];
        const symbolPattern = new RegExp(`([${mathSymbols.join('')}])`, 'g');
        formatted = formatted.replace(symbolPattern, '<span class="math-symbol">$1</span>');
        formatted = formatted.replace(/<span class="math-symbol"><span class="math-symbol">([^<]+)<\/span><\/span>/g, '<span class="math-symbol">$1</span>');
        
        return formatted;
    }

    _sanitizeUrl(url) {
        if (!url || typeof url !== 'string') return null;
        const trimmed = url.trim();
        if (trimmed.startsWith('javascript:') || trimmed.startsWith('data:')) return null;
        if (trimmed.startsWith('http://') || trimmed.startsWith('https://') || trimmed.startsWith('/')) {
            return trimmed;
        }
        return null;
    }

    _maskIp(ip) {
        // Show full IP address for admin panel
        if (!ip) return 'Unknown';
        return ip;
    }

    _formatTimeAgo(timestamp) {
        if (!timestamp) return 'Unknown';
        const date = new Date(timestamp);
        const now = new Date();
        const diff = now - date;
        
        const minutes = Math.floor(diff / 60000);
        const hours = Math.floor(diff / 3600000);
        const days = Math.floor(diff / 86400000);
        
        if (minutes < 1) return 'Just now';
        if (minutes < 60) return `${minutes}m ago`;
        if (hours < 24) return `${hours}h ago`;
        if (days < 7) return `${days}d ago`;
        return date.toLocaleDateString();
    }

    _formatDate(timestamp) {
        if (!timestamp) return 'Unknown';
        return new Date(timestamp).toLocaleDateString('en-US', {
            month: 'short', day: 'numeric', year: 'numeric'
        });
    }

    _formatTime(timestamp) {
        if (!timestamp) return '';
        return new Date(timestamp).toLocaleTimeString('en-US', {
            hour: 'numeric', minute: '2-digit', hour12: true
        });
    }
}

// ==================== INITIALIZE ====================
document.addEventListener('DOMContentLoaded', () => {
    window.adminPanel = new AdminPanel();
});