@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&display=swap');

/* ===== CSS Custom Properties ===== */
:root {
  --bg-primary: #0a0a0f;
  --bg-secondary: #12121a;
  --bg-tertiary: #1a1a2e;
  --bg-glass: rgba(26, 26, 46, 0.7);
  --bg-glass-hover: rgba(26, 26, 46, 0.9);

  --text-primary: #e8e8f0;
  --text-secondary: #9494b8;
  --text-muted: #5a5a7a;

  --accent-primary: #6c5ce7;
  --accent-secondary: #a855f7;
  --accent-gradient: linear-gradient(135deg, #6c5ce7 0%, #a855f7 50%, #ec4899 100%);
  --accent-glow: rgba(108, 92, 231, 0.3);

  --border-color: rgba(148, 148, 184, 0.12);
  --border-hover: rgba(148, 148, 184, 0.25);

  --success: #10b981;
  --error: #ef4444;
  --warning: #f59e0b;

  --sidebar-width: 320px;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 20px;

  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 30px var(--accent-glow);

  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s ease;
  --transition-slow: 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ===== Reset & Base ===== */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html, body, #root {
  height: 100%;
  width: 100%;
  overflow: hidden;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ===== App Layout ===== */
.app {
  display: flex;
  height: 100vh;
  width: 100vw;
  overflow: hidden;
  background: var(--bg-primary);
}

/* ===== Sidebar ===== */
.sidebar {
  width: var(--sidebar-width);
  min-width: var(--sidebar-width);
  height: 100vh;
  background: var(--bg-secondary);
  border-right: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  transition: all var(--transition-slow);
  position: relative;
  z-index: 10;
}

.sidebar.closed {
  width: 0;
  min-width: 0;
  overflow: hidden;
  border-right: none;
}

.sidebar-header {
  padding: 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--border-color);
  flex-shrink: 0;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.1rem;
  font-weight: 600;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.logo svg {
  stroke: var(--accent-primary);
  flex-shrink: 0;
}

.sidebar-toggle {
  background: none;
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  cursor: pointer;
  padding: 6px;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  justify-content: center;
}

.sidebar-toggle:hover {
  background: var(--bg-tertiary);
  color: var(--text-primary);
  border-color: var(--border-hover);
}

.sidebar-content {
  flex: 1;
  overflow-y: auto;
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.sidebar-content::-webkit-scrollbar {
  width: 4px;
}

.sidebar-content::-webkit-scrollbar-track {
  background: transparent;
}

.sidebar-content::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 2px;
}

.sidebar-footer {
  padding: 16px 20px;
  border-top: 1px solid var(--border-color);
  text-align: center;
  flex-shrink: 0;
}

.sidebar-footer p {
  font-size: 0.75rem;
  color: var(--text-muted);
  letter-spacing: 0.5px;
}

/* ===== Mobile Sidebar Toggle ===== */
.mobile-sidebar-toggle {
  position: fixed;
  top: 16px;
  left: 16px;
  z-index: 20;
  background: var(--bg-glass);
  backdrop-filter: blur(12px);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  cursor: pointer;
  padding: 10px;
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-md);
}

.mobile-sidebar-toggle:hover {
  background: var(--bg-glass-hover);
  border-color: var(--accent-primary);
  box-shadow: var(--shadow-glow);
}

/* ===== File Upload ===== */
.file-upload-container {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.drop-zone {
  border: 2px dashed var(--border-color);
  border-radius: var(--radius-lg);
  padding: 24px 16px;
  text-align: center;
  cursor: pointer;
  transition: all var(--transition-normal);
  background: var(--bg-primary);
  position: relative;
  overflow: hidden;
}

.drop-zone::before {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--accent-gradient);
  opacity: 0;
  transition: opacity var(--transition-normal);
  border-radius: var(--radius-lg);
}

.drop-zone:hover,
.drop-zone.dragging {
  border-color: var(--accent-primary);
  box-shadow: var(--shadow-glow);
}

.drop-zone:hover::before,
.drop-zone.dragging::before {
  opacity: 0.05;
}

.drop-zone.uploading {
  border-color: var(--accent-secondary);
  cursor: wait;
}

.drop-zone-content {
  position: relative;
  z-index: 1;
}

.upload-icon {
  color: var(--text-muted);
  margin-bottom: 8px;
  transition: color var(--transition-normal);
}

.drop-zone:hover .upload-icon {
  color: var(--accent-primary);
}

.drop-zone-text {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 4px;
}

.browse-link {
  color: var(--accent-primary);
  font-weight: 500;
  text-decoration: underline;
  text-underline-offset: 2px;
}

.drop-zone-hint {
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* Upload Spinner */
.upload-spinner {
  width: 32px;
  height: 32px;
  border: 3px solid var(--border-color);
  border-top-color: var(--accent-primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  margin: 0 auto 12px;
}

.upload-status {
  font-size: 0.85rem;
  color: var(--accent-secondary);
  font-weight: 500;
}

.upload-error {
  background: rgba(239, 68, 68, 0.1);
  border: 1px solid rgba(239, 68, 68, 0.3);
  color: var(--error);
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  font-size: 0.8rem;
}

.upload-success {
  background: rgba(16, 185, 129, 0.1);
  border: 1px solid rgba(16, 185, 129, 0.3);
  color: var(--success);
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  font-size: 0.8rem;
}

/* ===== Document List ===== */
.document-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.section-title {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.8px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border-color);
}

.section-title svg {
  opacity: 0.6;
}

.doc-count {
  background: var(--accent-primary);
  color: white;
  font-size: 0.65rem;
  padding: 2px 7px;
  border-radius: 10px;
  font-weight: 700;
  margin-left: auto;
}

.doc-items {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.doc-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 12px;
  border-radius: var(--radius-sm);
  background: var(--bg-primary);
  border: 1px solid transparent;
  transition: all var(--transition-fast);
}

.doc-item:hover {
  border-color: var(--border-hover);
  background: var(--bg-tertiary);
}

.doc-info {
  display: flex;
  align-items: center;
  gap: 8px;
  min-width: 0;
  flex: 1;
}

.doc-info svg {
  color: var(--accent-secondary);
  flex-shrink: 0;
  opacity: 0.7;
}

.doc-name {
  font-size: 0.82rem;
  color: var(--text-primary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.delete-btn {
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  padding: 4px;
  border-radius: 4px;
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  opacity: 0;
  flex-shrink: 0;
}

.doc-item:hover .delete-btn {
  opacity: 1;
}

.delete-btn:hover {
  color: var(--error);
  background: rgba(239, 68, 68, 0.1);
}

.no-documents {
  text-align: center;
  padding: 20px 8px;
}

.no-documents p {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.no-documents .hint {
  font-size: 0.75rem;
  margin-top: 4px;
}

/* Loading Shimmer */
.loading-shimmer {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 8px 0;
}

.shimmer-line {
  height: 40px;
  border-radius: var(--radius-sm);
  background: linear-gradient(90deg, var(--bg-tertiary) 25%, var(--bg-glass) 50%, var(--bg-tertiary) 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
}

.shimmer-line.short {
  width: 70%;
}

/* ===== Main Content ===== */
.main-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-width: 0;
  position: relative;
  background: var(--bg-primary);
}

/* ===== Chat Window ===== */
.chat-window {
  display: flex;
  flex-direction: column;
  height: 100%;
}

.chat-messages {
  flex: 1;
  overflow-y: auto;
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.chat-messages::-webkit-scrollbar {
  width: 6px;
}

.chat-messages::-webkit-scrollbar-track {
  background: transparent;
}

.chat-messages::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 3px;
}

/* Chat Empty State */
.chat-empty {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 40px;
  gap: 12px;
}

.chat-empty-icon {
  color: var(--text-muted);
  opacity: 0.4;
  margin-bottom: 8px;
}

.chat-empty h2 {
  font-size: 1.8rem;
  font-weight: 700;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.chat-empty p {
  font-size: 1rem;
  color: var(--text-secondary);
  max-width: 400px;
}

.chat-empty .hint {
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* Messages */
.message {
  display: flex;
  gap: 12px;
  padding: 16px 20px;
  border-radius: var(--radius-md);
  transition: background var(--transition-fast);
  max-width: 85%;
  animation: messageIn 0.3s ease;
}

.message.user {
  align-self: flex-end;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
}

.message.assistant {
  align-self: flex-start;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
}

.message.error .message-text {
  color: var(--error);
}

.message-avatar {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.message.user .message-avatar {
  background: var(--accent-gradient);
  color: white;
}

.message.assistant .message-avatar {
  background: linear-gradient(135deg, #10b981 0%, #059669 100%);
  color: white;
}

.message-content {
  flex: 1;
  min-width: 0;
}

.message-role {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 4px;
}

.message-text {
  font-size: 0.92rem;
  line-height: 1.65;
  color: var(--text-primary);
  white-space: pre-wrap;
  word-break: break-word;
}

/* Cursor Blink */
.cursor-blink {
  animation: blink 0.7s infinite;
  color: var(--accent-primary);
  font-weight: 300;
}

/* Sources */
.message-sources {
  margin-top: 12px;
  padding-top: 10px;
  border-top: 1px solid var(--border-color);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
}

.sources-label {
  font-size: 0.72rem;
  color: var(--text-muted);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.source-tag {
  font-size: 0.75rem;
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  padding: 3px 8px;
  border-radius: 12px;
  color: var(--text-secondary);
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

.relevance {
  font-size: 0.65rem;
  color: var(--accent-secondary);
  font-weight: 600;
}

/* ===== Chat Input ===== */
.chat-input-area {
  padding: 16px 24px 24px;
  border-top: 1px solid var(--border-color);
  background: var(--bg-secondary);
  flex-shrink: 0;
}

.no-docs-warning {
  background: rgba(245, 158, 11, 0.08);
  border: 1px solid rgba(245, 158, 11, 0.2);
  color: var(--warning);
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  font-size: 0.8rem;
  margin-bottom: 12px;
  text-align: center;
}

.chat-input-wrapper {
  display: flex;
  align-items: flex-end;
  gap: 10px;
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 8px 8px 8px 16px;
  transition: all var(--transition-fast);
}

.chat-input-wrapper:focus-within {
  border-color: var(--accent-primary);
  box-shadow: var(--shadow-glow);
}

.chat-input {
  flex: 1;
  background: none;
  border: none;
  color: var(--text-primary);
  font-family: inherit;
  font-size: 0.92rem;
  line-height: 1.5;
  resize: none;
  outline: none;
  padding: 6px 0;
  min-height: 20px;
  max-height: 120px;
}

.chat-input::placeholder {
  color: var(--text-muted);
}

.send-btn {
  width: 40px;
  height: 40px;
  border: none;
  border-radius: var(--radius-md);
  background: var(--accent-gradient);
  color: white;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.send-btn:hover:not(:disabled) {
  transform: scale(1.05);
  box-shadow: var(--shadow-glow);
}

.send-btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.send-spinner {
  width: 18px;
  height: 18px;
  border: 2px solid rgba(255, 255, 255, 0.3);
  border-top-color: white;
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

/* ===== Animations ===== */
@keyframes spin {
  to { transform: rotate(360deg); }
}

@keyframes blink {
  0%, 100% { opacity: 1; }
  50% { opacity: 0; }
}

@keyframes shimmer {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

@keyframes messageIn {
  from {
    opacity: 0;
    transform: translateY(8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .sidebar {
    position: fixed;
    top: 0;
    left: 0;
    height: 100vh;
    z-index: 100;
    box-shadow: var(--shadow-lg);
  }

  .sidebar.closed {
    transform: translateX(-100%);
  }

  .message {
    max-width: 95%;
  }

  .chat-messages {
    padding: 16px;
  }

  .chat-input-area {
    padding: 12px 16px 16px;
  }
}