/* ========================================
   MatrixVault - Main Stylesheet
   ======================================== */

/* CSS Variables */
:root {
  /* Colors */
  --color-primary: #3B82F6;
  --color-primary-dark: #2563EB;
  --color-primary-light: #60A5FA;
  --color-accent: #10B981;
  --color-accent-dark: #059669;
  
  --color-bg: #F0F2F5;
  --color-bg-alt: #E8EAED;
  --color-card: #FAFBFC;
  --color-text: #1F2937;
  --color-text-secondary: #6B7280;
  --color-text-light: #9CA3AF;
  --color-border: #E5E7EB;
  --color-border-light: #F3F4F6;
  
  /* Theme-aware colors */
  --color-header-bg: rgba(255, 255, 255, 0.9);
  --color-header-bg-scrolled: rgba(255, 255, 255, 0.98);
  --color-badge-primary-bg: rgba(59, 130, 246, 0.1);
  --color-badge-accent-bg: rgba(16, 185, 129, 0.1);
  --color-badge-danger-bg: rgba(239, 68, 68, 0.1);
  --color-code-bg: #1F2937;
  --color-code-text: #E5E7EB;
  
  /* Typography */
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 2rem;
  --font-size-4xl: 2.5rem;
  
  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --spacing-3xl: 4rem;
  
  /* Border Radius */
  --radius-sm: 0.25rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-full: 9999px;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
  --transition-slow: 350ms ease;
  
  /* Layout */
  --container-max: 1200px;
  --header-height: 64px;
}

/* Dark Theme */
html.dark {
  --color-bg: #0F172A;
  --color-bg-alt: #1E293B;
  --color-card: #1E293B;
  --color-text: #F1F5F9;
  --color-text-secondary: #94A3B8;
  --color-text-light: #64748B;
  --color-border: #334155;
  --color-border-light: #1E293B;
  --color-header-bg: rgba(15, 23, 42, 0.9);
  --color-header-bg-scrolled: rgba(15, 23, 42, 0.98);
  --color-badge-primary-bg: rgba(59, 130, 246, 0.2);
  --color-badge-accent-bg: rgba(16, 185, 129, 0.2);
  --color-badge-danger-bg: rgba(239, 68, 68, 0.2);
  --color-code-bg: #0F172A;
  --color-code-text: #E2E8F0;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.2);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -1px rgba(0, 0, 0, 0.2);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.3), 0 4px 6px -2px rgba(0, 0, 0, 0.2);
}

/* Theme Transition (added by JS after load to prevent flash) */
html.theme-transition,
html.theme-transition *,
html.theme-transition *::before,
html.theme-transition *::after {
  transition: background-color 300ms ease, color 300ms ease, border-color 300ms ease, box-shadow 300ms ease !important;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

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

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--color-primary-dark);
}

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

ul, ol {
  list-style: none;
}

/* Layout */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.section {
  padding: var(--spacing-3xl) 0;
}

.section-title {
  font-size: var(--font-size-3xl);
  font-weight: 700;
  color: var(--color-text);
  text-align: center;
  margin-bottom: var(--spacing-md);
}

.section-subtitle {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  text-align: center;
  margin-bottom: var(--spacing-2xl);
}

/* ========================================
   Header & Navigation
   ======================================== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background: var(--color-header-bg);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--color-border-light);
  z-index: 1000;
  transition: background var(--transition-normal), box-shadow var(--transition-normal);
}

.header.scrolled {
  background: var(--color-header-bg-scrolled);
  box-shadow: var(--shadow-sm);
}

.header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--color-text);
}

.logo-icon {
  width: 32px;
  height: 32px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-light));
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: var(--font-size-sm);
  font-weight: 700;
}

.nav {
  display: flex;
  align-items: center;
  gap: var(--spacing-xl);
}

.nav-link {
  font-size: var(--font-size-base);
  color: var(--color-text-secondary);
  font-weight: 500;
  padding: var(--spacing-sm) 0;
  position: relative;
  transition: color var(--transition-fast);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--color-primary);
  transform: scaleX(0);
  transition: transform var(--transition-fast);
}

.nav-link:hover,
.nav-link.active {
  color: var(--color-primary);
}

.nav-link.active::after,
.nav-link:hover::after {
  transform: scaleX(1);
}

/* Mobile Menu Toggle */
.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: var(--spacing-sm);
  background: none;
  border: none;
  cursor: pointer;
}

.menu-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

.menu-toggle.active span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.menu-toggle.active span:nth-child(2) {
  opacity: 0;
}

.menu-toggle.active span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* ========================================
   Buttons
   ======================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-lg);
  font-size: var(--font-size-base);
  font-weight: 500;
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
}

.btn-primary {
  background: var(--color-primary);
  color: white;
}

.btn-primary:hover {
  background: var(--color-primary-dark);
  color: white;
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn-secondary {
  background: var(--color-card);
  color: var(--color-text);
  border: 1px solid var(--color-border);
}

.btn-secondary:hover {
  background: var(--color-bg-alt);
  color: var(--color-text);
  border-color: var(--color-border);
}

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

.btn-accent:hover {
  background: var(--color-accent-dark);
  color: white;
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn-lg {
  padding: var(--spacing-md) var(--spacing-xl);
  font-size: var(--font-size-lg);
}

/* ========================================
   Cards
   ======================================== */
.card {
  background: var(--color-card);
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-border-light);
  transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

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

.card-icon {
  width: 48px;
  height: 48px;
  background: linear-gradient(135deg, var(--color-primary-light), var(--color-primary));
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--spacing-md);
  font-size: var(--font-size-xl);
}

.card-title {
  font-size: var(--font-size-xl);
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: var(--spacing-sm);
}

.card-text {
  font-size: var(--font-size-base);
  color: var(--color-text-secondary);
  line-height: 1.7;
}

/* ========================================
   Hero Section
   ======================================== */
.hero {
  padding-top: calc(var(--header-height) + var(--spacing-3xl));
  padding-bottom: var(--spacing-3xl);
  background: linear-gradient(180deg, var(--color-bg) 0%, var(--color-bg-alt) 100%);
  min-height: 80vh;
  display: flex;
  align-items: center;
}

.hero-content {
  text-align: center;
  max-width: 800px;
  margin: 0 auto;
}

.hero-badge {
  display: inline-block;
  padding: var(--spacing-xs) var(--spacing-md);
  background: var(--color-badge-primary-bg);
  color: var(--color-primary);
  font-size: var(--font-size-sm);
  font-weight: 500;
  border-radius: var(--radius-full);
  margin-bottom: var(--spacing-lg);
}

.hero-title {
  font-size: var(--font-size-4xl);
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.2;
  margin-bottom: var(--spacing-lg);
}

.hero-title span {
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-description {
  font-size: var(--font-size-xl);
  color: var(--color-text-secondary);
  line-height: 1.7;
  margin-bottom: var(--spacing-xl);
}

.hero-buttons {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
  flex-wrap: wrap;
}

/* ========================================
   Features Section
   ======================================== */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-xl);
}

/* ========================================
   Product Section
   ======================================== */
.product-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-3xl);
  align-items: center;
}

.product-info h3 {
  font-size: var(--font-size-2xl);
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: var(--spacing-md);
}

.product-info p {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  line-height: 1.7;
  margin-bottom: var(--spacing-lg);
}

.product-features {
  margin-bottom: var(--spacing-xl);
}

.product-features li {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) 0;
  color: var(--color-text-secondary);
}

.product-features li::before {
  content: '';
  width: 20px;
  height: 20px;
  background: var(--color-accent);
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.product-preview {
  background: var(--color-card);
  border-radius: var(--radius-xl);
  padding: var(--spacing-lg);
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--color-border-light);
}

.preview-slider {
  position: relative;
}

.preview-slides {
  position: relative;
  border-radius: var(--radius-md);
  overflow: hidden;
  aspect-ratio: 16/10;
  background: var(--color-bg-alt);
}

.preview-slide {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: contain;
  opacity: 0;
  transition: opacity var(--transition-slow);
  cursor: zoom-in;
  pointer-events: none;
}

.preview-slide.active {
  opacity: 1;
  pointer-events: auto;
}

.preview-controls {
  display: flex;
  justify-content: center;
  gap: var(--spacing-sm);
  margin-top: var(--spacing-md);
}

.preview-dot {
  width: 10px;
  height: 10px;
  border-radius: var(--radius-full);
  border: none;
  background: var(--color-border);
  cursor: pointer;
  padding: 0;
  transition: background var(--transition-fast), transform var(--transition-fast);
}

.preview-dot:hover {
  background: var(--color-primary-light);
}

.preview-dot.active {
  background: var(--color-primary);
  transform: scale(1.2);
}

.preview-captions {
  text-align: center;
  margin-top: var(--spacing-sm);
  min-height: 1.6em;
}

.preview-caption {
  display: none;
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}

.preview-caption.active {
  display: inline;
}

/* ========================================
   CTA Section
   ======================================== */
.cta {
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  color: white;
  text-align: center;
}

.cta .section-title {
  color: white;
}

.cta .section-subtitle {
  color: rgba(255, 255, 255, 0.8);
}

.cta .btn-secondary {
  background: var(--color-card);
  color: var(--color-primary);
  border: none;
}

.cta .btn-secondary:hover {
  background: var(--color-bg);
  color: var(--color-primary-dark);
}

/* ========================================
   Footer
   ======================================== */
.footer {
  background: var(--color-card);
  border-top: 1px solid var(--color-border-light);
  padding: var(--spacing-xl) 0;
}

.footer-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.footer-text {
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
}

.footer-links {
  display: flex;
  gap: var(--spacing-lg);
}

.footer-links a {
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
}

.footer-links a:hover {
  color: var(--color-primary);
}

.footer-bottom {
  margin-top: var(--spacing-lg);
  padding-top: var(--spacing-lg);
  border-top: 1px solid var(--color-border-light);
  text-align: center;
}

.footer-icp {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: var(--spacing-lg);
  flex-wrap: wrap;
  font-size: var(--font-size-xs);
  color: var(--color-text-light);
}

.footer-icp a {
  color: var(--color-text-light);
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
}

.footer-icp a:hover {
  color: var(--color-text-secondary);
}

.footer-icp img {
  width: 14px;
  height: 14px;
}

/* ========================================
   Documentation Page
   ======================================== */
.docs-layout {
  display: grid;
  grid-template-columns: 250px 1fr;
  gap: var(--spacing-2xl);
  padding-top: calc(var(--header-height) + var(--spacing-xl));
  min-height: 100vh;
}

.docs-sidebar {
  position: sticky;
  top: calc(var(--header-height) + var(--spacing-xl));
  height: fit-content;
  max-height: calc(100vh - var(--header-height) - var(--spacing-2xl));
  overflow-y: auto;
}

.docs-nav {
  background: var(--color-card);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  border: 1px solid var(--color-border-light);
}

.docs-nav-title {
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-text-light);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--spacing-md);
}

.docs-nav-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xs);
}

.docs-nav-link {
  display: block;
  padding: var(--spacing-sm) var(--spacing-md);
  color: var(--color-text-secondary);
  border-radius: var(--radius-md);
  font-size: var(--font-size-sm);
  transition: all var(--transition-fast);
}

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

.docs-nav-link.active {
  background: var(--color-badge-primary-bg);
  color: var(--color-primary);
  font-weight: 500;
}

.docs-content {
  background: var(--color-card);
  border-radius: var(--radius-lg);
  padding: var(--spacing-2xl);
  border: 1px solid var(--color-border-light);
  margin-bottom: var(--spacing-2xl);
}

.docs-content h1 {
  font-size: var(--font-size-3xl);
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: var(--spacing-lg);
  padding-bottom: var(--spacing-md);
  border-bottom: 1px solid var(--color-border-light);
}

.docs-content h2 {
  font-size: var(--font-size-2xl);
  font-weight: 600;
  color: var(--color-text);
  margin-top: var(--spacing-2xl);
  margin-bottom: var(--spacing-md);
}

.docs-content h3 {
  font-size: var(--font-size-xl);
  font-weight: 600;
  color: var(--color-text);
  margin-top: var(--spacing-xl);
  margin-bottom: var(--spacing-sm);
}

.docs-content p {
  color: var(--color-text-secondary);
  line-height: 1.8;
  margin-bottom: var(--spacing-md);
}

.docs-content ul,
.docs-content ol {
  margin-bottom: var(--spacing-md);
  padding-left: var(--spacing-xl);
}

.docs-content ul {
  list-style: disc;
}

.docs-content ol {
  list-style: decimal;
}

.docs-content li {
  color: var(--color-text-secondary);
  line-height: 1.8;
  margin-bottom: var(--spacing-sm);
}

.docs-content code {
  background: var(--color-bg-alt);
  padding: 0.2em 0.4em;
  border-radius: var(--radius-sm);
  font-size: 0.9em;
  font-family: "SF Mono", "Fira Code", "Consolas", monospace;
  color: var(--color-primary-dark);
}

.docs-content pre {
  background: var(--color-code-bg);
  color: var(--color-code-text);
  padding: var(--spacing-lg);
  border-radius: var(--radius-md);
  overflow-x: auto;
  margin-bottom: var(--spacing-md);
}

.docs-content pre code {
  background: none;
  padding: 0;
  color: inherit;
}

/* ========================================
   Download Page
   ======================================== */
.download-page {
  padding-top: calc(var(--header-height) + var(--spacing-2xl));
  padding-bottom: var(--spacing-3xl);
}

.download-hero {
  text-align: center;
  margin-bottom: var(--spacing-3xl);
}

.download-card {
  max-width: 600px;
  margin: 0 auto var(--spacing-3xl);
  text-align: center;
}

.download-card .card {
  padding: var(--spacing-2xl);
}

.download-icon {
  width: 80px;
  height: 80px;
  background: linear-gradient(135deg, var(--color-primary-light), var(--color-primary));
  border-radius: var(--radius-xl);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto var(--spacing-lg);
  font-size: var(--font-size-3xl);
}

.download-name {
  font-size: var(--font-size-2xl);
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: var(--spacing-sm);
}

.download-version {
  font-size: var(--font-size-lg);
  color: var(--color-primary);
  font-weight: 500;
  margin-bottom: var(--spacing-md);
}

.download-meta {
  display: flex;
  justify-content: center;
  gap: var(--spacing-xl);
  margin-bottom: var(--spacing-xl);
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
}

.download-btn {
  width: 100%;
  max-width: 300px;
}

.download-options {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
  flex-wrap: wrap;
  margin-top: var(--spacing-lg);
}

.download-options .download-btn {
  width: auto;
  min-width: 180px;
  max-width: none;
}

.btn-outline {
  background: transparent;
  border: 2px solid var(--color-border);
  color: var(--color-text);
  padding: var(--spacing-sm) var(--spacing-lg);
  border-radius: var(--radius-md);
  cursor: pointer;
  font-size: var(--font-size-base);
  font-weight: 500;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s ease;
}

.btn-outline:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  background: rgba(16, 185, 129, 0.05);
}

.requirements {
  background: var(--color-bg-alt);
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
  margin-bottom: var(--spacing-3xl);
}

.requirements h3 {
  font-size: var(--font-size-xl);
  font-weight: 600;
  margin-bottom: var(--spacing-md);
}

.requirements ul {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--spacing-md);
}

.requirements li {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  color: var(--color-text-secondary);
}

.requirements li::before {
  content: '';
  width: 8px;
  height: 8px;
  background: var(--color-accent);
  border-radius: var(--radius-full);
  flex-shrink: 0;
}

/* Version History Table */
.version-history {
  margin-bottom: var(--spacing-3xl);
}

.version-history h3 {
  font-size: var(--font-size-xl);
  font-weight: 600;
  margin-bottom: var(--spacing-lg);
}

.version-table {
  width: 100%;
  background: var(--color-card);
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--color-border-light);
}

.version-table th,
.version-table td {
  padding: var(--spacing-md) var(--spacing-lg);
  text-align: left;
}

.version-table th {
  background: var(--color-bg-alt);
  font-weight: 600;
  color: var(--color-text);
  font-size: var(--font-size-sm);
}

.version-table td {
  border-top: 1px solid var(--color-border-light);
  color: var(--color-text-secondary);
}

.version-table tr:hover td {
  background: var(--color-bg);
}

/* ========================================
   Changelog Page
   ======================================== */
.changelog-page {
  padding-top: calc(var(--header-height) + var(--spacing-2xl));
  padding-bottom: var(--spacing-3xl);
}

.changelog-hero {
  text-align: center;
  margin-bottom: var(--spacing-3xl);
}

.timeline {
  max-width: 800px;
  margin: 0 auto;
  position: relative;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 20px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--color-border);
}

.timeline-item {
  position: relative;
  padding-left: 60px;
  margin-bottom: var(--spacing-2xl);
}

.timeline-dot {
  position: absolute;
  left: 12px;
  top: 0;
  width: 18px;
  height: 18px;
  background: var(--color-primary);
  border-radius: var(--radius-full);
  border: 3px solid var(--color-bg);
}

.timeline-date {
  font-size: var(--font-size-sm);
  color: var(--color-text-light);
  margin-bottom: var(--spacing-sm);
}

.timeline-card {
  background: var(--color-card);
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
  border: 1px solid var(--color-border-light);
  box-shadow: var(--shadow-sm);
}

.timeline-version {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-md);
}

.timeline-version h3 {
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--color-text);
}

.version-tag {
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--radius-full);
  font-size: var(--font-size-xs);
  font-weight: 500;
}

.tag-new {
  background: var(--color-badge-accent-bg);
  color: var(--color-accent);
}

.tag-fix {
  background: var(--color-badge-danger-bg);
  color: #EF4444;
}

.tag-improve {
  background: var(--color-badge-primary-bg);
  color: var(--color-primary);
}

.timeline-changes {
  margin-top: var(--spacing-md);
}

.change-category {
  margin-bottom: var(--spacing-md);
}

.change-category h4 {
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: var(--spacing-sm);
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.change-category ul {
  padding-left: var(--spacing-lg);
  list-style: disc;
}

.change-category li {
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
  line-height: 1.7;
  margin-bottom: var(--spacing-xs);
}

/* ========================================
   Theme Toggle Button
   ======================================== */
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  padding: 0;
  background: none;
  border: none;
  border-radius: var(--radius-full);
  cursor: pointer;
  color: var(--color-text-secondary);
  transition: background var(--transition-fast), color var(--transition-fast);
}

.theme-toggle:hover {
  background: var(--color-bg-alt);
  color: var(--color-text);
}

.theme-toggle svg {
  width: 20px;
  height: 20px;
}

.theme-toggle .icon-sun {
  display: none;
}

html.dark .theme-toggle .icon-sun {
  display: block;
}

html.dark .theme-toggle .icon-moon {
  display: none;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

/* ========================================
   Responsive Design
   ======================================== */
@media (max-width: 1024px) {
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .product-content {
    grid-template-columns: 1fr;
    gap: var(--spacing-2xl);
  }
  
  .product-preview {
    order: -1;
  }
}

@media (max-width: 768px) {
  :root {
    --font-size-4xl: 2rem;
    --font-size-3xl: 1.75rem;
    --font-size-2xl: 1.25rem;
  }
  
  .nav {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    height: calc(100vh - var(--header-height));
    background: var(--color-card);
    flex-direction: column;
    padding: var(--spacing-xl);
    gap: var(--spacing-md);
    overflow-y: auto;
    z-index: 999;
  }
  
  .nav.active {
    display: flex;
  }
  
  .nav-link {
    font-size: var(--font-size-lg);
    padding: var(--spacing-md);
    border-bottom: 1px solid var(--color-border-light);
  }
  
  .nav-link::after {
    display: none;
  }
  
  .menu-toggle {
    display: flex;
  }
  
  .features-grid {
    grid-template-columns: 1fr;
  }
  
  .hero-buttons {
    flex-direction: column;
    align-items: center;
  }
  
  .hero-buttons .btn {
    width: 100%;
    max-width: 300px;
  }
  
  .footer-content {
    flex-direction: column;
    gap: var(--spacing-md);
    text-align: center;
  }
  
  /* Docs Layout */
  .docs-layout {
    grid-template-columns: 1fr;
  }
  
  .docs-sidebar {
    position: relative;
    top: 0;
    max-height: none;
  }
  
  /* Download Meta */
  .download-meta {
    flex-direction: column;
    gap: var(--spacing-sm);
  }
  
  /* Timeline */
  .timeline::before {
    left: 10px;
  }
  
  .timeline-item {
    padding-left: 40px;
  }
  
  .timeline-dot {
    left: 2px;
    width: 16px;
    height: 16px;
  }
}

/* ========================================
   Utility Classes
   ======================================== */
.text-center {
  text-align: center;
}

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

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

.mt-sm { margin-top: var(--spacing-sm); }

/* ========================================
   Lightbox
   ======================================== */
.lightbox-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.85);
  z-index: 2000;
  cursor: zoom-out;
  align-items: center;
  justify-content: center;
}

.lightbox-overlay.active {
  display: flex;
}

.lightbox-overlay img {
  max-width: 92vw;
  max-height: 92vh;
  object-fit: contain;
  border-radius: var(--radius-md);
  box-shadow: 0 0 40px rgba(0, 0, 0, 0.5);
  animation: lightbox-in 0.25s ease;
}

@keyframes lightbox-in {
  from { opacity: 0; transform: scale(0.92); }
  to   { opacity: 1; transform: scale(1); }
}

.lightbox-close {
  position: absolute;
  top: 20px;
  right: 24px;
  width: 36px;
  height: 36px;
  background: rgba(255, 255, 255, 0.15);
  border: none;
  border-radius: var(--radius-full);
  color: #fff;
  font-size: 22px;
  line-height: 36px;
  text-align: center;
  cursor: pointer;
  transition: background var(--transition-fast);
}

.lightbox-close:hover {
  background: rgba(255, 255, 255, 0.3);
}
.mt-md { margin-top: var(--spacing-md); }
.mt-lg { margin-top: var(--spacing-lg); }
.mt-xl { margin-top: var(--spacing-xl); }

.mb-sm { margin-bottom: var(--spacing-sm); }
.mb-md { margin-bottom: var(--spacing-md); }
.mb-lg { margin-bottom: var(--spacing-lg); }
.mb-xl { margin-bottom: var(--spacing-xl); }