/* ===== CSS Variables (Theme System) ===== */
:root {
  /* Light theme (default) */
  --bg-primary: #F8FAFC;
  --bg-secondary: #F1F5F9;
  --bg-tertiary: #E2E8F0;
  --bg-code: #1E293B;
  --bg-card: #FFFFFF;
  --bg-navbar: rgba(248, 250, 252, 0.85);
  --text-primary: #0F172A;
  --text-secondary: #475569;
  --text-tertiary: #64748B;
  --text-code: #E2E8F0;
  --border: #E2E8F0;
  --border-light: #F1F5F9;
  --accent: #2563EB;
  --accent-hover: #1D4ED8;
  --accent-light: #3B82F6;
  --accent-bg: rgba(37, 99, 235, 0.08);
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.07), 0 2px 4px -2px rgba(0, 0, 0, 0.05);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.08), 0 4px 6px -4px rgba(0, 0, 0, 0.04);
  --hero-gradient: linear-gradient(135deg, #F8FAFC 0%, #EFF6FF 50%, #F8FAFC 100%);
  --code-dot-opacity: 1;
  color-scheme: light;
}

[data-theme="dark"] {
  --bg-primary: #0F172A;
  --bg-secondary: #1E293B;
  --bg-tertiary: #334155;
  --bg-code: #0D1117;
  --bg-card: #1E293B;
  --bg-navbar: rgba(15, 23, 42, 0.85);
  --text-primary: #F1F5F9;
  --text-secondary: #94A3B8;
  --text-tertiary: #64748B;
  --text-code: #E2E8F0;
  --border: #334155;
  --border-light: #1E293B;
  --accent: #3B82F6;
  --accent-hover: #60A5FA;
  --accent-light: #60A5FA;
  --accent-bg: rgba(59, 130, 246, 0.12);
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -2px rgba(0, 0, 0, 0.2);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -4px rgba(0, 0, 0, 0.2);
  --hero-gradient: linear-gradient(135deg, #0F172A 0%, #1E293B 50%, #0F172A 100%);
  --code-dot-opacity: 0.8;
  color-scheme: dark;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.2s;
}

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

/* ===== Navbar ===== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: var(--bg-navbar);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  transition: background 0.3s, border-color 0.3s;
}

.navbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.navbar-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text-primary);
  font-weight: 700;
  font-size: 1.25rem;
}

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

.brand-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, #2563EB, #3B82F6);
  color: #fff;
  font-weight: 800;
  font-size: 1.1rem;
  border-radius: 8px;
  flex-shrink: 0;
}

.brand-text {
  letter-spacing: -0.02em;
}

.navbar-links {
  display: flex;
  align-items: center;
  gap: 32px;
}

.navbar-links a {
  color: var(--text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
  transition: color 0.2s;
}

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

.navbar-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

/* Theme Toggle */
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg-card);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.2s;
}

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

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

/* Show correct icon based on theme state (controlled by JS) */
.theme-toggle[data-mode="light"] .icon-sun { display: block; }
.theme-toggle[data-mode="dark"] .icon-moon { display: block; }
.theme-toggle[data-mode="device"] .icon-monitor { display: block; }

/* Mobile Menu Button */
.mobile-menu-btn {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  padding: 8px;
  background: none;
  border: 1px solid var(--border);
  border-radius: 8px;
  cursor: pointer;
}

.mobile-menu-btn span {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--text-secondary);
  border-radius: 1px;
  transition: all 0.3s;
}

.mobile-menu-btn.active span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}
.mobile-menu-btn.active span:nth-child(2) {
  opacity: 0;
}
.mobile-menu-btn.active span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ===== Hero ===== */
.hero {
  padding: 120px 0 80px;
  background: var(--hero-gradient);
  overflow: hidden;
}

.hero-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}

.hero-title {
  display: flex;
  align-items: center;
  gap: 16px;
  font-size: 3.5rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.1;
  margin-bottom: 16px;
}

.hero-logo {
  width: 64px;
  height: 64px;
  font-size: 2rem;
  border-radius: 16px;
}

.hero-tagline {
  font-size: 1.25rem;
  color: var(--accent);
  font-weight: 600;
  margin-bottom: 12px;
}

.hero-description {
  font-size: 1.1rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 32px;
  max-width: 520px;
}

.hero-actions {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  font-size: 1rem;
  font-weight: 600;
  border-radius: 10px;
  border: none;
  cursor: pointer;
  transition: all 0.2s;
  text-decoration: none;
}

.btn-primary {
  background: linear-gradient(135deg, #2563EB, #3B82F6);
  color: #fff;
  box-shadow: 0 4px 14px rgba(37, 99, 235, 0.35);
}

.btn-primary:hover {
  background: linear-gradient(135deg, #1D4ED8, #2563EB);
  box-shadow: 0 6px 20px rgba(37, 99, 235, 0.45);
  color: #fff;
  transform: translateY(-1px);
}

.btn-secondary {
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
}

.btn-secondary:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-bg);
  transform: translateY(-1px);
}

.btn-outline {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 20px;
  font-size: 0.9rem;
  font-weight: 600;
  border-radius: 8px;
  border: 1px solid var(--accent);
  color: var(--accent);
  background: transparent;
  cursor: pointer;
  transition: all 0.2s;
  text-decoration: none;
  margin-top: 12px;
}

.btn-outline:hover {
  background: var(--accent-bg);
  color: var(--accent-hover);
}

/* ===== Code Window ===== */
.code-window {
  border-radius: 12px;
  overflow: hidden;
  background: var(--bg-code);
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--border);
}

.code-header {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 12px 16px;
  background: rgba(0, 0, 0, 0.2);
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.code-dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  opacity: var(--code-dot-opacity);
}

.code-dot.red { background: #FF5F57; }
.code-dot.yellow { background: #FEBC2E; }
.code-dot.green { background: #28C840; }

.code-filename {
  margin-left: 8px;
  font-family: 'JetBrains Mono', 'Fira Code', monospace;
  font-size: 0.8rem;
  color: #94A3B8;
}

.code-body {
  padding: 20px;
  overflow-x: auto;
  font-family: 'JetBrains Mono', 'Fira Code', monospace;
  font-size: 0.85rem;
  line-height: 1.7;
  color: var(--text-code);
  margin: 0;
}

.code-body code {
  font-family: inherit;
}

.code-window-sm .code-body {
  font-size: 0.82rem;
  padding: 16px;
}

/* Syntax Highlighting */
.kd-keyword { color: #C084FC; font-weight: 500; }
.kd-type { color: #67E8F9; }
.kd-func { color: #60A5FA; }
.kd-string { color: #86EFAC; }
.kd-number { color: #FCA5A5; }
.kd-comment { color: #64748B; font-style: italic; }
.kd-ivar { color: #FB923C; }
.kd-symbol { color: #FDE047; }
.kd-ident { color: #A5B4FC; }

/* ===== Sections ===== */
.section-title {
  font-size: 2.25rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  text-align: center;
  margin-bottom: 12px;
}

.section-subtitle {
  text-align: center;
  color: var(--text-secondary);
  font-size: 1.1rem;
  margin-bottom: 48px;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

/* ===== Features ===== */
.features {
  padding: 100px 0;
  background: var(--bg-secondary);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 28px;
  transition: all 0.2s;
}

.feature-card:hover {
  border-color: var(--accent);
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.feature-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  background: var(--accent-bg);
  color: var(--accent);
  border-radius: 10px;
  margin-bottom: 16px;
}

.feature-card h3 {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.feature-card p {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ===== Examples ===== */
.examples {
  padding: 100px 0;
}

.tabs {
  max-width: 800px;
  margin: 0 auto;
}

.tab-bar {
  display: flex;
  gap: 4px;
  border-bottom: 2px solid var(--border);
  margin-bottom: 0;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}

.tab-bar::-webkit-scrollbar {
  display: none;
}

.tab-btn {
  padding: 12px 20px;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-tertiary);
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  margin-bottom: -2px;
  cursor: pointer;
  transition: all 0.2s;
  white-space: nowrap;
}

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

.tab-btn.active {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

.tab-panel {
  display: none;
}

.tab-panel.active {
  display: block;
}

/* ===== Installation ===== */
.install {
  padding: 100px 0;
  background: var(--bg-secondary);
}

.install-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.install-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 28px;
}

.install-card h3 {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 20px;
  color: var(--text-primary);
}

.install-card h3 svg {
  color: var(--accent);
  flex-shrink: 0;
}

.install-options {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 8px;
}

.install-link {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 14px;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text-primary);
  font-size: 0.9rem;
  font-weight: 500;
  transition: all 0.2s;
}

.install-link:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-bg);
}

.install-badge {
  display: inline-block;
  padding: 2px 8px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.78rem;
  font-weight: 600;
  background: var(--accent-bg);
  color: var(--accent);
  border-radius: 4px;
}

/* ===== Docs ===== */
.docs {
  padding: 100px 0;
}

.docs-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.docs-card {
  display: block;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 28px;
  color: var(--text-primary);
  transition: all 0.2s;
}

.docs-card:hover {
  border-color: var(--accent);
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
  color: var(--text-primary);
}

.docs-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  background: var(--accent-bg);
  color: var(--accent);
  border-radius: 10px;
  margin-bottom: 16px;
}

.docs-card h3 {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.docs-card p {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

/* ===== Footer ===== */
.footer {
  padding: 64px 0 32px;
  background: var(--bg-secondary);
  border-top: 1px solid var(--border);
}

.footer-content {
  display: flex;
  justify-content: space-between;
  gap: 48px;
  margin-bottom: 48px;
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.footer-brand .brand-icon {
  width: 40px;
  height: 40px;
  font-size: 1.2rem;
}

.footer-brand .brand-text {
  font-size: 1.3rem;
  font-weight: 700;
}

.footer-tagline {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-top: 4px;
}

.footer-links {
  display: flex;
  gap: 64px;
}

.footer-col {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-col h4 {
  font-size: 0.85rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-tertiary);
  margin-bottom: 4px;
}

.footer-col a {
  color: var(--text-secondary);
  font-size: 0.9rem;
  transition: color 0.2s;
}

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

.footer-bottom {
  border-top: 1px solid var(--border);
  padding-top: 24px;
  text-align: center;
}

.footer-bottom p {
  font-size: 0.85rem;
  color: var(--text-tertiary);
}

/* ===== Responsive ===== */
@media (max-width: 1024px) {
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }

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

  .hero-content {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .hero-title {
    font-size: 2.75rem;
  }
}

@media (max-width: 768px) {
  .navbar-links {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    flex-direction: column;
    gap: 0;
    background: var(--bg-navbar);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
    padding: 8px 0;
  }

  .navbar-links.active {
    display: flex;
  }

  .navbar-links a {
    padding: 12px 24px;
    width: 100%;
  }

  .mobile-menu-btn {
    display: flex;
  }

  .hero {
    padding: 100px 0 60px;
  }

  .hero-title {
    font-size: 2.25rem;
  }

  .hero-logo {
    width: 48px;
    height: 48px;
    font-size: 1.5rem;
    border-radius: 12px;
  }

  .hero-description {
    font-size: 1rem;
  }

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

  .section-title {
    font-size: 1.75rem;
  }

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

  .tab-btn {
    padding: 10px 14px;
    font-size: 0.82rem;
  }

  .footer-content {
    flex-direction: column;
    gap: 32px;
  }

  .footer-links {
    flex-wrap: wrap;
    gap: 32px;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 16px;
  }

  .hero-title {
    font-size: 1.75rem;
  }

  .hero-actions {
    flex-direction: column;
  }

  .btn {
    justify-content: center;
    width: 100%;
  }

  .code-body {
    font-size: 0.78rem;
    padding: 14px;
  }
}