/* AI Knowledge Base - Dark Theme CSS
   ================================== */

/* CSS Custom Properties */
:root {
  /* Colors */
  --bg-primary: #0a0a0f;
  --bg-secondary: #12121a;
  --bg-card: #1a1a24;
  --bg-elevated: #22222e;
  --bg-sidebar: #0d0d14;
  
  --text-primary: #f0f0f5;
  --text-secondary: #a0a0b0;
  --text-muted: #606070;
  
  --accent: #6366f1;
  --accent-hover: #818cf8;
  --accent-light: rgba(99, 102, 241, 0.15);
  --accent-glow: rgba(99, 102, 241, 0.3);
  
  --success: #10b981;
  --warning: #f59e0b;
  --error: #ef4444;
  
  /* Borders & Shadows */
  --border: rgba(255, 255, 255, 0.06);
  --border-strong: rgba(255, 255, 255, 0.12);
  --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 12px 40px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 20px rgba(99, 102, 241, 0.2);
  
  /* Gradients */
  --gradient-hero: linear-gradient(135deg, rgba(99, 102, 241, 0.15) 0%, rgba(168, 85, 247, 0.1) 50%, rgba(236, 72, 153, 0.05) 100%);
  --gradient-accent: linear-gradient(135deg, #6366f1 0%, #a855f7 100%);
  
  /* Typography */
  --font-display: 'Inter', system-ui, -apple-system, sans-serif;
  --font-body: 'Inter', system-ui, -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Consolas', monospace;
  
  /* Layout */
  --sidebar-width: 280px;
  --content-max-width: 900px;
  --spacing-xs: 4px;
  --spacing-sm: 8px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 32px;
  --spacing-2xl: 48px;
  --spacing-3xl: 64px;
  
  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-normal: 0.2s ease;
  --transition-slow: 0.3s ease;
  
  /* Border Radius */
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-full: 100px;
}

/* ===================
   Reset & Base Styles
   =================== */

*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  background: var(--bg-primary);
  scroll-padding-top: var(--spacing-xl);
}

body {
  font-family: var(--font-body);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
}

/* Links */
a {
  color: inherit;
  text-decoration: none;
  transition: color var(--transition-fast);
}

/* Images */
img {
  max-width: 100%;
  height: auto;
  display: block;
}

/* Lists */
ul, ol {
  list-style-position: inside;
}

/* ===================
   Skip Link (A11y)
   =================== */

.skip-link {
  position: absolute;
  top: -100%;
  left: var(--spacing-md);
  z-index: 9999;
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--accent);
  color: white;
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 0.9rem;
  transition: top var(--transition-fast);
}

.skip-link:focus {
  top: var(--spacing-md);
  outline: 2px solid white;
  outline-offset: 2px;
}

/* ===================
   Focus States (A11y)
   =================== */

:focus {
  outline: none;
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* Remove focus outline for mouse users */
:focus:not(:focus-visible) {
  outline: none;
}

/* ===================
   Layout
   =================== */

.layout {
  display: flex;
  min-height: 100vh;
}

/* ===================
   Sidebar
   =================== */

.sidebar {
  position: fixed;
  left: 0;
  top: 0;
  width: var(--sidebar-width);
  height: 100vh;
  background: var(--bg-sidebar);
  border-right: 1px solid var(--border);
  overflow-y: auto;
  z-index: 100;
  display: flex;
  flex-direction: column;
  transition: transform var(--transition-slow);
}

.sidebar-header {
  padding: var(--spacing-lg) var(--spacing-lg);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  background: var(--bg-sidebar);
  z-index: 10;
}

.sidebar-logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

.sidebar-logo:hover .logo-text {
  color: var(--accent);
}

.logo-icon {
  width: 40px;
  height: 40px;
  background: var(--gradient-accent);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  box-shadow: var(--shadow-glow);
  flex-shrink: 0;
}

.logo-icon svg {
  width: 22px;
  height: 22px;
}

.logo-text {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--text-primary);
  transition: color var(--transition-fast);
}

.logo-subtitle {
  font-size: 0.7rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

/* Sidebar Navigation */
.sidebar-nav {
  flex: 1;
  padding: var(--spacing-md) 0;
  overflow-y: auto;
}

/* Collapsible Nav Sections */
.nav-section {
  margin-bottom: var(--spacing-sm);
}

.nav-section-toggle {
  display: block;
  width: 100%;
  padding: var(--spacing-md) var(--spacing-lg) var(--spacing-sm);
  font-size: 0.7rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  background: none;
  border: none;
  cursor: pointer;
  text-align: left;
  transition: color var(--transition-fast);
}

.nav-section-toggle:hover {
  color: var(--text-secondary);
}

.nav-section-toggle::before {
  content: '▸';
  display: inline-block;
  margin-right: var(--spacing-sm);
  transition: transform var(--transition-fast);
}

.nav-section[open] .nav-section-toggle::before {
  transform: rotate(90deg);
}

.nav-section-title {
  padding: var(--spacing-md) var(--spacing-lg) var(--spacing-sm);
  font-size: 0.7rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.nav-links {
  list-style: none;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  padding: 10px var(--spacing-lg);
  color: var(--text-secondary);
  font-size: 0.9rem;
  transition: all var(--transition-fast);
  border-left: 3px solid transparent;
}

.nav-link:hover {
  background: var(--bg-elevated);
  color: var(--text-primary);
}

.nav-link.active {
  background: var(--accent-light);
  color: var(--accent);
  border-left-color: var(--accent);
}

.nav-link svg {
  width: 18px;
  height: 18px;
  opacity: 0.7;
  flex-shrink: 0;
}

.nav-link.active svg {
  opacity: 1;
}

/* Sidebar Footer */
.sidebar-footer {
  padding: var(--spacing-md) var(--spacing-lg);
  border-top: 1px solid var(--border);
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* ===================
   Main Content
   =================== */

.main-content {
  flex: 1;
  margin-left: var(--sidebar-width);
  min-height: 100vh;
  animation: fadeIn 0.4s ease-out;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ===================
   Mobile Menu Toggle
   =================== */

.menu-toggle {
  display: none;
  position: fixed;
  top: var(--spacing-md);
  left: var(--spacing-md);
  z-index: 200;
  width: 44px;
  height: 44px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  cursor: pointer;
  align-items: center;
  justify-content: center;
  color: var(--text-primary);
  transition: all var(--transition-fast);
}

.menu-toggle:hover {
  background: var(--bg-elevated);
  border-color: var(--accent);
}

.menu-toggle svg {
  width: 24px;
  height: 24px;
}

.sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.7);
  z-index: 90;
  backdrop-filter: blur(4px);
}

/* ===================
   Page Header
   =================== */

.page-header {
  padding: 80px var(--spacing-2xl) var(--spacing-2xl);
  background: var(--gradient-hero);
  border-bottom: 1px solid var(--border);
  position: relative;
  overflow: hidden;
}

.page-header::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, var(--accent-glow) 0%, transparent 70%);
  pointer-events: none;
}

.page-header h1 {
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 700;
  margin-bottom: var(--spacing-md);
  position: relative;
}

.page-header p {
  font-size: 1.1rem;
  color: var(--text-secondary);
  max-width: 600px;
  position: relative;
}

/* Breadcrumb */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-md);
  font-size: 0.85rem;
  color: var(--text-muted);
}

.breadcrumb a {
  color: var(--accent);
}

.breadcrumb a:hover {
  color: var(--accent-hover);
}

/* ===================
   Page Content
   =================== */

.page-content {
  padding: var(--spacing-2xl);
  max-width: var(--content-max-width);
}

/* Typography */
.page-content h2 {
  font-size: 1.75rem;
  font-weight: 700;
  margin: var(--spacing-2xl) 0 var(--spacing-lg);
  color: var(--text-primary);
  position: relative;
  scroll-margin-top: var(--spacing-xl);
}

.page-content h2:first-child {
  margin-top: 0;
}

.page-content h3 {
  font-size: 1.35rem;
  font-weight: 600;
  margin: var(--spacing-xl) 0 var(--spacing-md);
  color: var(--text-primary);
  scroll-margin-top: var(--spacing-xl);
}

.page-content h4 {
  font-size: 1.1rem;
  font-weight: 600;
  margin: var(--spacing-lg) 0 var(--spacing-md);
  color: var(--text-primary);
  scroll-margin-top: var(--spacing-xl);
}

.page-content p {
  color: var(--text-secondary);
  margin-bottom: var(--spacing-lg);
  font-size: 1.05rem;
  line-height: 1.8;
}

.page-content ul,
.page-content ol {
  color: var(--text-secondary);
  margin-bottom: var(--spacing-lg);
  padding-left: var(--spacing-lg);
  line-height: 1.8;
  list-style-position: outside;
}

.page-content li {
  margin-bottom: 10px;
}

.page-content strong {
  color: var(--text-primary);
  font-weight: 600;
}

.page-content a {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
}

.page-content a:hover {
  color: var(--accent-hover);
}

/* Anchor Links for Headings */
.heading-anchor {
  color: var(--text-muted);
  text-decoration: none;
  margin-left: var(--spacing-sm);
  opacity: 0;
  transition: opacity var(--transition-fast);
}

.page-content h2:hover .heading-anchor,
.page-content h3:hover .heading-anchor,
.page-content h4:hover .heading-anchor,
.heading-anchor:focus {
  opacity: 1;
}

/* ===================
   Info Cards
   =================== */

.info-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  margin: var(--spacing-lg) 0;
}

.info-card.highlight {
  border-color: var(--accent);
  background: var(--accent-light);
}

.info-card.success {
  border-color: var(--success);
  background: rgba(16, 185, 129, 0.1);
}

.info-card.warning {
  border-color: var(--warning);
  background: rgba(245, 158, 11, 0.1);
}

.info-card h4 {
  margin-top: 0;
  color: var(--accent);
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.info-card.success h4 {
  color: var(--success);
}

.info-card.warning h4 {
  color: var(--warning);
}

.info-card p:last-child {
  margin-bottom: 0;
}

/* ===================
   Code Blocks
   =================== */

.code-block {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: var(--spacing-lg);
  margin: var(--spacing-lg) 0;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  overflow-x: auto;
  color: var(--text-secondary);
}

code {
  background: var(--bg-elevated);
  padding: 2px var(--spacing-sm);
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: 0.85em;
  color: var(--accent);
}

pre code {
  background: none;
  padding: 0;
}

/* ===================
   Feature Grid
   =================== */

.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-lg);
  margin: var(--spacing-xl) 0;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  transition: all var(--transition-slow);
}

.feature-card:hover {
  border-color: var(--accent);
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.feature-card h4 {
  margin-top: 0;
  display: flex;
  align-items: center;
  gap: 10px;
}

.feature-icon {
  width: 40px;
  height: 40px;
  background: var(--accent-light);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent);
  flex-shrink: 0;
}

/* ===================
   Stats Grid
   =================== */

.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: var(--spacing-md);
  margin: var(--spacing-xl) 0;
}

.stat-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: var(--spacing-lg);
  text-align: center;
  transition: border-color var(--transition-fast);
}

.stat-card:hover {
  border-color: var(--accent);
}

.stat-value {
  font-size: 2rem;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: var(--spacing-xs);
}

.stat-label {
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* ===================
   Tables
   =================== */

.table-container {
  overflow-x: auto;
  margin: var(--spacing-lg) 0;
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
}

table {
  width: 100%;
  border-collapse: collapse;
  background: var(--bg-card);
  min-width: 500px;
}

th, td {
  padding: var(--spacing-md) var(--spacing-lg);
  text-align: left;
  border-bottom: 1px solid var(--border);
}

th {
  background: var(--bg-elevated);
  font-weight: 600;
  color: var(--text-primary);
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  position: sticky;
  top: 0;
}

td {
  color: var(--text-secondary);
}

tr:last-child td {
  border-bottom: none;
}

tr:hover td {
  background: var(--bg-elevated);
}

/* ===================
   Blockquote
   =================== */

blockquote {
  border-left: 4px solid var(--accent);
  padding: var(--spacing-md) var(--spacing-lg);
  margin: var(--spacing-lg) 0;
  background: var(--bg-card);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  font-style: italic;
  color: var(--text-secondary);
}

blockquote p {
  margin-bottom: 0;
}

/* ===================
   Timeline
   =================== */

.timeline {
  position: relative;
  padding-left: var(--spacing-xl);
  margin: var(--spacing-xl) 0;
}

.timeline::before {
  content: '';
  position: absolute;
  left: var(--spacing-sm);
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--border-strong);
}

.timeline-item {
  position: relative;
  padding-bottom: var(--spacing-xl);
}

.timeline-item:last-child {
  padding-bottom: 0;
}

.timeline-item::before {
  content: '';
  position: absolute;
  left: -28px;
  top: 4px;
  width: 12px;
  height: 12px;
  background: var(--accent);
  border-radius: 50%;
  border: 3px solid var(--bg-primary);
}

.timeline-date {
  font-size: 0.85rem;
  color: var(--accent);
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
}

.timeline-content h4 {
  margin: 0 0 var(--spacing-sm);
}

.timeline-content p {
  margin: 0;
}

/* ===================
   Page Navigation
   =================== */

.page-nav {
  display: flex;
  justify-content: space-between;
  gap: var(--spacing-lg);
  margin-top: var(--spacing-3xl);
  padding-top: var(--spacing-xl);
  border-top: 1px solid var(--border);
}

.page-nav-link {
  flex: 1;
  max-width: 300px;
  padding: var(--spacing-lg);
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.page-nav-link:hover {
  border-color: var(--accent);
  background: var(--bg-elevated);
  transform: translateX(4px);
}

.page-nav-link.prev:hover {
  transform: translateX(-4px);
}

.page-nav-link.next {
  text-align: right;
  margin-left: auto;
}

.page-nav-label {
  font-size: 0.75rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: var(--spacing-xs);
}

.page-nav-title {
  color: var(--text-primary);
  font-weight: 600;
}

/* ===================
   Hero Section (Home)
   =================== */

.hero-section {
  padding: 100px var(--spacing-2xl) 80px;
  background: var(--gradient-hero);
  position: relative;
  overflow: hidden;
  text-align: center;
}

.hero-section::before {
  content: '';
  position: absolute;
  top: -30%;
  left: 50%;
  transform: translateX(-50%);
  width: 800px;
  height: 800px;
  background: radial-gradient(circle, var(--accent-glow) 0%, transparent 60%);
  pointer-events: none;
}

.hero-badge {
  display: inline-block;
  background: var(--accent-light);
  color: var(--accent);
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--radius-full);
  font-size: 0.8rem;
  font-weight: 600;
  margin-bottom: var(--spacing-lg);
  position: relative;
}

.hero-title {
  font-size: clamp(2.5rem, 6vw, 4rem);
  font-weight: 700;
  margin-bottom: var(--spacing-lg);
  line-height: 1.1;
  position: relative;
}

.hero-title span {
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-description {
  font-size: 1.2rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto 40px;
  position: relative;
}

/* ===================
   Topic Cards (Home)
   =================== */

.topics-section {
  padding: var(--spacing-3xl) var(--spacing-2xl);
}

.section-header {
  display: flex;
  align-items: center;
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-xl);
}

.section-header h2 {
  font-size: 1.5rem;
  font-weight: 700;
  white-space: nowrap;
  margin: 0;
}

.section-line {
  flex: 1;
  height: 1px;
  background: var(--border-strong);
}

.topics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: var(--spacing-lg);
}

.topic-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px;
  transition: all var(--transition-slow);
  display: flex;
  flex-direction: column;
}

.topic-card:hover {
  border-color: var(--accent);
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.topic-icon {
  width: 48px;
  height: 48px;
  background: var(--accent-light);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent);
  margin-bottom: var(--spacing-md);
}

.topic-icon svg {
  width: 24px;
  height: 24px;
}

.topic-card h3 {
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
  color: var(--text-primary);
}

.topic-card p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.6;
  flex: 1;
  margin: 0;
}

.topic-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--accent);
  font-weight: 500;
  font-size: 0.9rem;
  margin-top: var(--spacing-md);
  transition: gap var(--transition-fast);
}

.topic-link:hover {
  gap: 10px;
}

/* ===================
   Footer
   =================== */

.footer {
  padding: var(--spacing-xl) var(--spacing-2xl);
  border-top: 1px solid var(--border);
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
}

/* ===================
   404 Page
   =================== */

.error-page {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: var(--spacing-2xl);
  text-align: center;
}

.error-code {
  font-size: clamp(6rem, 20vw, 12rem);
  font-weight: 700;
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1;
  margin-bottom: var(--spacing-lg);
}

.error-page h1 {
  font-size: 1.5rem;
  margin-bottom: var(--spacing-md);
}

.error-page p {
  color: var(--text-secondary);
  margin-bottom: var(--spacing-xl);
  max-width: 400px;
}

.error-link {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-md) var(--spacing-lg);
  background: var(--accent);
  color: white;
  border-radius: var(--radius-md);
  font-weight: 600;
  transition: all var(--transition-fast);
}

.error-link:hover {
  background: var(--accent-hover);
  transform: translateY(-2px);
}

/* ===================
   Responsive Design
   =================== */

@media (max-width: 900px) {
  .sidebar {
    transform: translateX(-100%);
  }

  .sidebar.open {
    transform: translateX(0);
  }

  .sidebar-overlay.open {
    display: block;
  }

  .menu-toggle {
    display: flex;
  }

  .main-content {
    margin-left: 0;
  }

  .page-header,
  .page-content,
  .hero-section,
  .topics-section {
    padding-left: var(--spacing-lg);
    padding-right: var(--spacing-lg);
  }

  .page-header {
    padding-top: 100px;
  }

  .hero-section {
    padding-top: 120px;
  }

  .page-nav {
    flex-direction: column;
  }

  .page-nav-link {
    max-width: none;
  }

  .page-nav-link.next {
    text-align: left;
  }

  .page-nav-link:hover {
    transform: translateY(-2px);
  }
}

@media (max-width: 600px) {
  .topics-grid {
    grid-template-columns: 1fr;
  }

  .feature-grid {
    grid-template-columns: 1fr;
  }

  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .hero-title {
    font-size: 2rem;
  }

  .page-content h2 {
    font-size: 1.5rem;
  }

  .page-content h3 {
    font-size: 1.2rem;
  }
  
  .table-container {
    margin-left: calc(-1 * var(--spacing-lg));
    margin-right: calc(-1 * var(--spacing-lg));
    border-radius: 0;
    border-left: none;
    border-right: none;
  }
}

/* ===================
   Scrollbar Styling
   =================== */

::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

::-webkit-scrollbar-track {
  background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
  background: var(--border-strong);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--text-muted);
}

/* Firefox */
* {
  scrollbar-width: thin;
  scrollbar-color: var(--border-strong) var(--bg-secondary);
}

/* ===================
   Selection
   =================== */

::selection {
  background: var(--accent);
  color: white;
}

/* ===================
   Print Styles
   =================== */

@media print {
  *,
  *::before,
  *::after {
    background: white !important;
    color: black !important;
    box-shadow: none !important;
    text-shadow: none !important;
  }
  
  .sidebar,
  .menu-toggle,
  .sidebar-overlay,
  .page-nav,
  .skip-link {
    display: none !important;
  }
  
  .main-content {
    margin-left: 0 !important;
  }
  
  .page-header {
    padding: 20px 0 !important;
    border-bottom: 2px solid #333 !important;
  }
  
  .page-content {
    padding: 20px 0 !important;
    max-width: 100% !important;
  }
  
  a {
    text-decoration: underline !important;
  }
  
  a[href^="http"]::after {
    content: " (" attr(href) ")";
    font-size: 0.8em;
    color: #666 !important;
  }
  
  h2, h3, h4 {
    page-break-after: avoid;
  }
  
  .info-card,
  .feature-card,
  .topic-card {
    border: 1px solid #ccc !important;
    page-break-inside: avoid;
  }
  
  table {
    border: 1px solid #ccc !important;
  }
  
  th, td {
    border: 1px solid #ccc !important;
  }
  
  .heading-anchor {
    display: none !important;
  }
  
  .footer {
    border-top: 1px solid #ccc !important;
    padding: 10px 0 !important;
  }
}

/* ===================
   Utility Classes
   =================== */

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.text-center {
  text-align: center;
}

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

.mt-0 { margin-top: 0; }
.mb-0 { margin-bottom: 0; }