components/header.js

class CustomHeader extends HTMLElement {
    connectedCallback() {
        this.attachShadow({ mode: 'open' });
        this.shadowRoot.innerHTML = `
            <style>
                :host {
                    display: block;
                    width: 100%;
                }
                
                header {
                    background: rgba(17, 24, 39, 0.8);
                    backdrop-filter: blur(10px);
                    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
                }
                
                .nav-link {
                    position: relative;
                    transition: all 0.3s ease;
                }
                
                .nav-link:hover {
                    color: #0ea5e9;
                }
                
                .nav-link::after {
                    content: '';
                    position: absolute;
                    bottom: -2px;
                    left: 0;
                    width: 0;
                    height: 2px;
                    background: #0ea5e9;
                    transition: width 0.3s ease;
                }
                
                .nav-link:hover::after {
                    width: 100%;
                }
                
                .mobile-menu {
                    transform: translateX(-100%);
                    transition: transform 0.3s ease;
                }
                
                .mobile-menu.open {
                    transform: translateX(0);
                }
                
                @media (max-width: 768px) {
                    .desktop-nav {
                        display: none;
                    }
                }
            </style>
            
            <header class="sticky top-0 z-50">
                <nav class="container mx-auto px-4 py-4">
                    <div class="flex items-center justify-between">
                        <!-- Logo -->
                        <div class="flex items-center space-x-2">
                            <i data-feather="moon" class="w-8 h-8 text-primary-400"></i>
                            <span class="text-xl font-bold bg-gradient-to-r from-primary-400 to-secondary-500 bg-clip-text text-transparent">
                                Celestial Symphony
                            </span>
                        </div>
                        
                        <!-- Desktop Navigation -->
                        <div class="desktop-nav hidden md:flex items-center space-x-8">
                            <a href="#demo" class="nav-link text-gray-300 hover:text-primary-300">
                                <i data-feather="play" class="w-4 h-4 inline mr-2"></i>
                                Demo
                            </a>
                            <a href="#documentation" class="nav-link text-gray-300 hover:text-primary-300">
                                <i data-feather="book" class="w-4 h-4 inline mr-2"></i>
                                Docs
                            </a>
                            <a href="#" class="nav-link text-gray-300 hover:text-primary-300">
                                <i data-feather="download" class="w-4 h-4 inline mr-2"></i>
                                Download
                            </a>
                        </div>
                        
                        <!-- Mobile Menu Button -->
                        <button id="mobileMenuBtn" class="md:hidden text-gray-300 hover:text-primary-300">
                                <i data-feather="menu" class="w-6 h-6"></i>
                            </button>
                    </div>
                    
                    <!-- Mobile Navigation -->
                    <div id="mobileMenu" class="mobile-menu fixed inset-y-0 left-0 w-64 bg-gray-900 p-6 md:hidden">
                        <div class="flex justify-between items-center mb-8">
                            <span class="text-lg font-bold text-primary-300">Menu</span>
                            <button id="closeMobileMenu" class="text-gray-400 hover:text-white">
                            <i data-feather="x" class="w-6 h-6"></i>
                        </div>
                        
                        <div class="space-y-6">
                            <a href="#demo" class="block nav-link text-gray-300 hover:text-primary-300">
                                <i data-feather="play" class="w-4 h-4 inline mr-3"></i>
                                Live Demo
                            </a>
                            <a href="#documentation" class="block nav-link text-gray-300 hover:text-primary-300">
                                <i data-feather="book" class="w-4 h-4 inline mr-3"></i>
                                Documentation
                            </a>
                            <a href="#" class="block nav-link text-gray-300 hover:text-primary-300">
                                <i data-feather="download" class="w-4 h-4 inline mr-3"></i>
                                Download Package
                            </a>
                        </div>
                        
                        <div class="absolute bottom-6 left-6 right-6">
                            <div class="flex items-center space-x-4 text-sm text-gray-400">
                                <i data-feather="github" class="w-4 h-4"></i>
                                <span>View on GitHub</span>
                            </div>
                        </div>
                    </div>
                </nav>
            </header>
            
            <script>
                // Initialize mobile menu functionality
                document.addEventListener('DOMContentLoaded', () => {
                    const mobileMenuBtn = this.shadowRoot.getElementById('mobileMenuBtn');
                    const closeMobileMenu = this.shadowRoot.getElementById('closeMobileMenu');
                    const mobileMenu = this.shadowRoot.getElementById('mobileMenu');
                    
                    mobileMenuBtn?.addEventListener('click', () => {
                        mobileMenu?.classList.add('open');
                    });
                    
                    closeMobileMenu?.addEventListener('click', () => {
                        mobileMenu?.classList.remove('open');
                    });
                    
                    // Close mobile menu when clicking outside
                    document.addEventListener('click', (e) => {
                        if (!mobileMenu?.contains(e.target) && !mobileMenuBtn?.contains(e.target)) {
                            mobileMenu?.classList.remove('open');
                        }
                    });
                });
            </script>
        `;
        
        // Initialize Feather Icons in shadow DOM
        setTimeout(() => {
            if (window.feather) {
                window.feather.replace({ scope: this.shadowRoot });
        }, 100);
    }
}

customElements.define('custom-header', CustomHeader);