/* ========================================
   Octopuses — Design Tokens & Global Styles
   Inspired by openakita.ai
   ======================================== */

/* -------- Design Tokens -------- */
:root {
  /* Primary palette — deep ocean blue */
  --color-primary-50: #eef5ff;
  --color-primary-100: #d9e8ff;
  --color-primary-200: #bcd4ff;
  --color-primary-300: #8eb5ff;
  --color-primary-400: #598bff;
  --color-primary-500: #3366ff;
  --color-primary-600: #1a4bdf;
  --color-primary-700: #143ab5;
  --color-primary-800: #153194;
  --color-primary-900: #172c78;

  /* Accent — teal/cyan for highlights */
  --color-accent-400: #22d3ee;
  --color-accent-500: #06b6d4;
  --color-accent-600: #0891b2;

  /* Purple accent for gradient */
  --color-purple-400: #a78bfa;
  --color-purple-500: #8b5cf6;
  --color-purple-600: #7c3aed;

  /* Surface — dark theme */
  --surface-bg: #0a0e17;
  --surface-1: #0f141e;
  --surface-2: #161c2a;
  --surface-3: #1e2535;
  --surface-4: #252d3f;

  /* Text */
  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-tertiary: #64748b;
  --text-muted: #475569;

  /* Borders */
  --border-default: rgba(255,255,255,0.06);
  --border-strong: rgba(255,255,255,0.10);
  --border-accent: rgba(51,102,255,0.25);

  /* Extra theme tokens */
  --surface-0: #0a0e17;
  --accent-orange: #d19a66;
  --accent-green: #28c840;

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', monospace;

  /* Spacing */
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 20px;
  --space-6: 24px;
  --space-8: 32px;
  --space-10: 40px;
  --space-12: 48px;
  --space-16: 64px;
  --space-20: 80px;
  --space-24: 96px;

  /* Radii */
  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-2xl: 24px;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.4);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.5);
  --shadow-lg: 0 8px 32px rgba(0,0,0,0.6);
  --shadow-glow: 0 0 40px rgba(51,102,255,0.15);
  --shadow-glow-purple: 0 0 40px rgba(139,92,246,0.12);

  /* Transitions */
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-in-out: cubic-bezier(0.65, 0, 0.35, 1);
  --transition-fast: 150ms var(--ease-out);
  --transition-base: 300ms var(--ease-out);
  --transition-slow: 500ms var(--ease-out);

  /* Layout */
  --nav-height: 64px;
  --max-width: 1200px;
}

/* -------- Light Theme -------- */
[data-theme="light"] {
  /* Surface — light theme */
  --surface-bg: #f8fafc;
  --surface-0: #f1f5f9;
  --surface-1: #ffffff;
  --surface-2: #f1f5f9;
  --surface-3: #e2e8f0;
  --surface-4: #cbd5e1;

  /* Text */
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-tertiary: #64748b;
  --text-muted: #94a3b8;

  /* Borders */
  --border-default: rgba(0,0,0,0.06);
  --border-strong: rgba(0,0,0,0.10);
  --border-accent: rgba(51,102,255,0.15);

  /* Shadows — lighter for light theme */
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
  --shadow-lg: 0 8px 32px rgba(0,0,0,0.10);
  --shadow-glow: 0 0 40px rgba(51,102,255,0.10);
  --shadow-glow-purple: 0 0 40px rgba(139,92,246,0.08);

  /* Syntax colors for code blocks — light bg */
  --code-keyword: #8250df;
  --code-string: #0a7a28;
  --code-function: #0550ae;
  --code-comment: #6e7781;
  --code-number: #953800;
  --code-operator: #0550ae;
}

[data-theme="light"] .nav {
  background: rgba(255,255,255,0.85);
  border-bottom-color: var(--border-default);
}
[data-theme="light"] .nav.scrolled {
  background: rgba(255,255,255,0.95);
  border-bottom-color: var(--border-strong);
}

[data-theme="light"] ::selection {
  background: rgba(51,102,255,0.2);
  color: #0f172a;
}

[data-theme="light"] .hero::before {
  background: radial-gradient(circle, rgba(51,102,255,0.05) 0%, transparent 60%);
}

[data-theme="light"] .hero-badge {
  color: var(--color-primary-600);
  background: rgba(51,102,255,0.06);
  border-color: rgba(51,102,255,0.12);
}

[data-theme="light"] .feature-card {
  background: var(--surface-1);
}
[data-theme="light"] .feature-card:hover {
  box-shadow: 0 8px 32px rgba(0,0,0,0.06);
}

[data-theme="light"] .terminal-mockup {
  box-shadow: var(--shadow-lg);
}
[data-theme="light"] .terminal-header {
  background: var(--surface-2);
}

[data-theme="light"] .step-number {
  box-shadow: 0 2px 8px rgba(51,102,255,0.25);
}

[data-theme="light"] .nav-links a.active {
  background: rgba(51,102,255,0.08);
}
[data-theme="light"] .theme-toggle:hover {
  background: var(--surface-3);
}

[data-theme="light"] ::-webkit-scrollbar-track { background: var(--surface-0); }
[data-theme="light"] ::-webkit-scrollbar-thumb { background: var(--surface-3); }
[data-theme="light"] ::-webkit-scrollbar-thumb:hover { background: var(--surface-4); }

/* Fix code syntax colors for light */
[data-theme="light"] .doc-code-block .kw { color: var(--code-keyword); }
[data-theme="light"] .doc-code-block .str { color: var(--code-string); }
[data-theme="light"] .doc-code-block .fn { color: var(--code-function); }
[data-theme="light"] .doc-code-block .cm { color: var(--code-comment); }
[data-theme="light"] .doc-code-block .num { color: var(--code-number); }
[data-theme="light"] .doc-code-block .op { color: var(--code-operator); }

[data-theme="light"] .doc-callout.tip { background: rgba(6,182,212,0.04); }
[data-theme="light"] .doc-callout.warning { background: rgba(210,153,34,0.04); }
[data-theme="light"] .doc-callout.note { background: rgba(51,102,255,0.04); }

/* Inline code contrast fix for light theme */
[data-theme="light"] .step-content code,
[data-theme="light"] .doc-content code,
[data-theme="light"] .prompt-vars-table code {
  color: var(--color-primary-600);
  background: var(--surface-2);
}
[data-theme="light"] .terminal-body .prompt {
  color: var(--color-primary-600);
}
[data-theme="light"] .terminal-body .highlight {
  color: var(--color-primary-600);
}

/* Light theme footer adjustment */
[data-theme="light"] .footer {
  background: var(--surface-1);
}

/* Tab-style override for light theme */
[data-theme="light"] .api-method.get {
  color: #0e7490;
}
[data-theme="light"] .api-method.post {
  color: #6d28d9;
}

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

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  background: var(--surface-bg);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
  transition: background var(--transition-base), color var(--transition-base);
}

::selection { background: rgba(51,102,255,0.3); color: #fff; }

::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--surface-1); }
::-webkit-scrollbar-thumb { background: var(--surface-4); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-muted); }

img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }
button { cursor: pointer; font-family: inherit; border: none; outline: none; background: none; }

/* -------- Utility -------- */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-6);
}

.section {
  padding: var(--space-24) 0;
}

/* Standalone page — used when content is a full page (not a section in SPA) */
.page {
  padding-top: calc(var(--nav-height) + var(--space-12));
  padding-bottom: var(--space-20);
  min-height: calc(100vh - 300px); /* account for footer */
}

.page-hero {
  text-align: center;
  margin-bottom: var(--space-16);
}

.section-label {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-primary-400);
  margin-bottom: var(--space-3);
}

.section-title {
  font-size: clamp(1.8rem, 4vw, 2.8rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.2;
  margin-bottom: var(--space-4);
  color: var(--text-primary);
}

.section-subtitle {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 600px;
  line-height: 1.7;
}

.text-gradient {
  background: linear-gradient(135deg, var(--color-primary-300) 0%, var(--color-accent-400) 50%, var(--color-purple-400) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* -------- Buttons -------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: 12px 28px;
  font-size: 0.9rem;
  font-weight: 600;
  border-radius: var(--radius-full);
  transition: all var(--transition-base);
  white-space: nowrap;
  letter-spacing: -0.01em;
}

.btn-primary {
  background: linear-gradient(135deg, var(--color-primary-500), var(--color-primary-600));
  color: #fff;
  box-shadow: 0 4px 20px rgba(51,102,255,0.3);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(51,102,255,0.45);
}

.btn-secondary {
  background: var(--surface-3);
  color: var(--text-primary);
  border: 1px solid var(--border-strong);
}
.btn-secondary:hover {
  background: var(--surface-4);
  border-color: var(--border-accent);
  transform: translateY(-2px);
}

.btn-ghost {
  color: var(--text-secondary);
  padding: 8px 16px;
  font-weight: 500;
}
.btn-ghost:hover { color: var(--text-primary); background: var(--surface-2); }

/* -------- Navigation -------- */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--nav-height);
  background: rgba(10,14,23,0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-default);
  transition: background var(--transition-base), border-color var(--transition-base), backdrop-filter var(--transition-base);
}
.nav.scrolled {
  background: rgba(10,14,23,0.95);
  border-bottom-color: var(--border-strong);
}

.nav-inner {
  display: flex;
  align-items: center;
  height: 100%;
}

.nav-brand {
  flex-shrink: 0;
}
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-weight: 700;
  font-size: 1.2rem;
  letter-spacing: -0.02em;
  color: var(--text-primary);
}
.nav-brand img { width: 36px; height: 36px; }
.nav-brand-text {
  background: linear-gradient(135deg, var(--color-primary-300), var(--color-accent-500));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  margin-right: auto;
  padding-left: 100px;
}
.nav-links a {
  padding: 8px 16px;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}
.nav-links a:hover { color: var(--text-primary); background: var(--surface-2); }
.nav-links a.active {
  color: var(--text-primary);
  background: rgba(51,102,255,0.1);
}

.nav-cta {
  margin-left: var(--space-4);
  padding: 8px 20px;
  font-size: 0.85rem;
}

/* Right-side actions (language, theme toggle, hamburger) */
.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  flex-shrink: 0;
}

/* -------- Language Selector -------- */
.lang-selector {
  position: relative;
  z-index: 100;
}

.lang-btn {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 0 10px;
  height: 32px;
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  font-size: 0.82rem;
  font-weight: 500;
  transition: all var(--transition-fast);
  background: var(--surface-2);
  border: 1px solid var(--border-default);
  cursor: pointer;
  white-space: nowrap;
}
.lang-btn:hover {
  color: var(--text-primary);
  background: var(--surface-3);
  border-color: var(--border-strong);
}
.lang-btn .fa-globe {
  font-size: 0.85rem;
  color: var(--color-primary-400);
}
.lang-current {
  min-width: 2em;
  text-align: center;
}
.lang-arrow {
  font-size: 0.5rem !important;
  transition: transform var(--transition-fast);
  color: var(--text-tertiary);
}
.lang-selector.open .lang-arrow {
  transform: rotate(180deg);
}

.lang-menu {
  position: absolute;
  top: calc(100% + 6px);
  right: 0;
  min-width: 130px;
  background: var(--surface-1);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-lg);
  padding: var(--space-2);
  box-shadow: 0 8px 32px rgba(0,0,0,0.35);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-4px);
  transition: all var(--transition-fast);
  list-style: none;
}
.lang-selector.open .lang-menu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.lang-menu li {
  padding: 8px 14px;
  font-size: 0.82rem;
  color: var(--text-secondary);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all var(--transition-fast);
  white-space: nowrap;
  display: flex;
  align-items: center;
  gap: 8px;
}
.lang-menu li:hover {
  color: var(--text-primary);
  background: var(--surface-2);
}
.lang-menu li.active {
  color: var(--color-primary-400);
  background: rgba(51,102,255,0.08);
  font-weight: 600;
}
.lang-menu li.active::before {
  content: '✓';
  font-size: 0.7rem;
  color: var(--color-primary-400);
}

/* Light theme adjustments */
[data-theme="light"] .lang-btn {
  background: var(--surface-2);
  border-color: var(--border-default);
}
[data-theme="light"] .lang-btn:hover {
  background: var(--surface-3);
}
[data-theme="light"] .lang-menu {
  box-shadow: 0 8px 32px rgba(0,0,0,0.12);
}

/* -------- Theme Toggle Button -------- */
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  font-size: 1rem;
  transition: all var(--transition-fast);
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
}
.theme-toggle:hover {
  color: var(--text-primary);
  background: var(--surface-2);
}

/* Mobile nav toggle */
.nav-toggle {
  display: none;
  width: 40px;
  height: 40px;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  font-size: 1.2rem;
}

/* -------- Hero -------- */
.hero {
  padding: calc(var(--nav-height) + var(--space-20)) 0 var(--space-20);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  left: 50%;
  transform: translateX(-50%);
  width: 900px;
  height: 900px;
  background: radial-gradient(circle, rgba(51,102,255,0.08) 0%, transparent 60%);
  pointer-events: none;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: 6px 16px;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--color-primary-300);
  background: rgba(51,102,255,0.08);
  border: 1px solid rgba(51,102,255,0.15);
  border-radius: var(--radius-full);
  margin-bottom: var(--space-8);
  letter-spacing: 0.04em;
}

.hero-title {
  font-size: clamp(2.4rem, 6vw, 4.2rem);
  font-weight: 800;
  letter-spacing: -0.04em;
  line-height: 1.1;
  margin-bottom: var(--space-6);
}

.hero-subtitle {
  font-size: clamp(1rem, 2vw, 1.2rem);
  color: var(--text-secondary);
  max-width: 640px;
  margin: 0 auto var(--space-10);
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-4);
  flex-wrap: wrap;
  margin-bottom: var(--space-16);
}

.hero-scroll {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-2);
  color: var(--text-tertiary);
  font-size: 0.8rem;
  transition: color var(--transition-fast);
}
.hero-scroll:hover { color: var(--text-secondary); }
.hero-scroll-icon {
  width: 24px;
  height: 24px;
  animation: scrollBounce 2s ease-in-out infinite;
}

@keyframes scrollBounce {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(6px); }
}

/* -------- Features Grid -------- */
.features-header {
  text-align: center;
  margin-bottom: var(--space-16);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-6);
}

.feature-card {
  background: var(--surface-1);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-xl);
  padding: var(--space-8);
  transition: background var(--transition-base), border-color var(--transition-base), box-shadow var(--transition-base), transform var(--transition-base);
  position: relative;
  overflow: hidden;
}
.feature-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--color-primary-500), transparent);
  opacity: 0;
  transition: opacity var(--transition-base);
}
.feature-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-accent);
  box-shadow: var(--shadow-glow);
}
.feature-card:hover::before { opacity: 1; }

.feature-icon {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-lg);
  background: rgba(51,102,255,0.1);
  color: var(--color-primary-400);
  font-size: 1.4rem;
  margin-bottom: var(--space-5);
}

.feature-card h3 {
  font-size: 1.1rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  margin-bottom: var(--space-3);
  color: var(--text-primary);
}

.feature-card p {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* -------- Quick Start -------- */
.quickstart {
  position: relative;
}

.quickstart-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-16);
  align-items: center;
}

.quickstart-text .section-title { margin-bottom: var(--space-4); }
.quickstart-text .section-subtitle { margin-bottom: var(--space-8); }

.quickstart-steps {
  display: flex;
  flex-direction: column;
  gap: var(--space-5);
}

.step {
  display: flex;
  gap: var(--space-4);
  align-items: flex-start;
}

.step-number {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-full);
  background: linear-gradient(135deg, var(--color-primary-500), var(--color-primary-700));
  color: #fff;
  font-weight: 700;
  font-size: 0.9rem;
  flex-shrink: 0;
}

.step-content h4 {
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 2px;
  color: var(--text-primary);
}

.step-content p {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.step-content code {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  background: var(--surface-2);
  padding: 1px 6px;
  border-radius: 3px;
  color: var(--color-accent-400);
  border: 1px solid var(--border-default);
}

/* Terminal mockup */
.terminal-mockup {
  background: var(--surface-1);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: var(--shadow-lg), var(--shadow-glow);
  transition: background var(--transition-base), box-shadow var(--transition-base), border-color var(--transition-base);
}

.terminal-header {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 12px 16px;
  background: var(--surface-2);
  border-bottom: 1px solid var(--border-default);
}
.terminal-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}
.terminal-dot.red { background: #ff5f57; }
.terminal-dot.yellow { background: #febc2e; }
.terminal-dot.green { background: #28c840; }
.terminal-title {
  margin-left: var(--space-3);
  font-size: 0.75rem;
  color: var(--text-tertiary);
  font-family: var(--font-mono);
}

.terminal-body {
  padding: var(--space-5);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  line-height: 1.8;
  color: var(--text-secondary);
}

.terminal-body .prompt { color: var(--color-accent-400); }
.terminal-body .cmd { color: var(--text-primary); }
.terminal-body .output { color: var(--text-tertiary); }
.terminal-body .highlight { color: var(--color-primary-400); }
.terminal-body .success { color: #28c840; }

/* -------- API Section -------- */
.api-header {
  text-align: center;
  margin-bottom: var(--space-16);
}

.api-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-5);
}

.api-card {
  background: var(--surface-1);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-lg);
  padding: var(--space-5) var(--space-6);
  transition: all var(--transition-base);
}
.api-card:hover {
  border-color: var(--border-strong);
  box-shadow: var(--shadow-md);
}

.api-method {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 700;
  padding: 2px 8px;
  border-radius: 3px;
  margin-bottom: var(--space-3);
}
.api-method.get { background: rgba(34,211,238,0.1); color: var(--color-accent-400); }
.api-method.post { background: rgba(139,92,246,0.12); color: var(--color-purple-400); }

.api-card .api-path {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--text-primary);
  margin-bottom: var(--space-2);
  word-break: break-all;
}

.api-card .api-desc {
  font-size: 0.8rem;
  color: var(--text-tertiary);
  line-height: 1.5;
}

/* -------- Architecture Section -------- */
.arch-diagram {
  background: var(--surface-1);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-xl);
  padding: var(--space-10);
  max-width: 900px;
  margin: 0 auto;
}

.arch-flow {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-4);
  flex-wrap: nowrap;
  width: auto;
}

.arch-node {
  background: var(--surface-2);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-lg);
  padding: var(--space-4) var(--space-6);
  text-align: center;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-primary);
  transition: all var(--transition-base);
  min-width: 100px;
  flex: 1;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  align-self: stretch;
  white-space: nowrap;
}
.arch-node:hover {
  border-color: var(--border-accent);
  box-shadow: var(--shadow-glow);
}
.arch-node.accent {
  background: rgba(51,102,255,0.08);
  border-color: var(--border-accent);
}
.arch-arrow {
  color: var(--text-tertiary);
  font-size: 1.2rem;
  font-weight: 300;
  flex-shrink: 0;
}

/* -------- Footer -------- */
.footer {
  background: var(--surface-1);
  border-top: 1px solid var(--border-default);
  padding: var(--space-16) 0 var(--space-8);
  transition: background var(--transition-base), border-color var(--transition-base);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--space-12);
  margin-bottom: var(--space-12);
}

.footer-brand h4 {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: var(--space-3);
  letter-spacing: -0.02em;
}

.footer-brand p {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: var(--space-5);
  max-width: 300px;
}

.footer-social {
  display: flex;
  gap: var(--space-3);
}
.footer-social a {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  background: var(--surface-2);
  color: var(--text-tertiary);
  font-size: 0.9rem;
  transition: all var(--transition-fast);
  border: 1px solid var(--border-default);
}
.footer-social a:hover {
  background: var(--surface-3);
  color: var(--text-primary);
  border-color: var(--border-strong);
}

/* WeChat QR Code Hover Effect */
.wechat-container {
  position: relative;
  display: inline-block;
}

.wechat-qr {
  position: absolute;
  bottom: calc(100% + 10px);
  left: 50%;
  transform: translateX(-50%) translateY(10px);
  background: var(--surface-1);
  padding: 10px;
  border-radius: var(--radius-md);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.15);
  border: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  z-index: 100;
  width: 140px;
  pointer-events: none; /* 防止在隐藏状态下阻挡点击 */
}

/* Little triangle pointer */
.wechat-qr::after {
  content: '';
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  border-width: 6px;
  border-style: solid;
  border-color: var(--surface-1) transparent transparent transparent;
}

.wechat-qr img {
  width: 120px;
  height: 120px;
  object-fit: cover;
  border-radius: var(--radius-sm);
  background: #fff; /* fallback for transparent images */
}

.wechat-qr span {
  font-size: 0.75rem;
  color: var(--text-secondary);
  white-space: nowrap;
}

.wechat-container.show-qr .wechat-qr {
  opacity: 1;
  visibility: visible;
  transform: translateX(-50%) translateY(0);
  pointer-events: auto;
}

.footer-col h4 {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-tertiary);
  margin-bottom: var(--space-5);
}

.footer-col ul {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.footer-col a {
  font-size: 0.85rem;
  color: var(--text-secondary);
  transition: color var(--transition-fast);
}
.footer-col a:hover { color: var(--text-primary); }

.footer-bottom {
  padding-top: var(--space-8);
  border-top: 1px solid var(--border-default);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-4);
  font-size: 0.8rem;
  color: var(--text-tertiary);
}

.footer-bottom a {
  color: var(--text-secondary);
  transition: color var(--transition-fast);
}
.footer-bottom a:hover { color: var(--text-primary); }

/* -------- Animations -------- */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s var(--ease-out), transform 0.6s var(--ease-out);
}
.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Stagger children */
.stagger-children > * {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.5s var(--ease-out), transform 0.5s var(--ease-out);
}
.stagger-children.reveal > *:nth-child(1) { transition-delay: 0.05s; }
.stagger-children.reveal > *:nth-child(2) { transition-delay: 0.1s; }
.stagger-children.reveal > *:nth-child(3) { transition-delay: 0.15s; }
.stagger-children.reveal > *:nth-child(4) { transition-delay: 0.2s; }
.stagger-children.reveal > *:nth-child(5) { transition-delay: 0.25s; }
.stagger-children.reveal > *:nth-child(6) { transition-delay: 0.3s; }
.stagger-children.reveal > * {
  opacity: 1;
  transform: translateY(0);
}

/* -------- Responsive -------- */
@media (max-width: 1024px) {
  .features-grid { grid-template-columns: repeat(2, 1fr); }
  .api-grid { grid-template-columns: repeat(2, 1fr); }
  .quickstart-inner { grid-template-columns: 1fr; gap: var(--space-10); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 768px) {
  :root { --nav-height: 56px; }
  .section { padding: var(--space-16) 0; }
  .container { padding: 0 var(--space-4); }

  .nav-links { display: none; }
  .nav-links.open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--surface-1);
    border-bottom: 1px solid var(--border-default);
    padding: var(--space-4);
    gap: var(--space-2);
  }
  .nav-links.open a { padding: 10px 16px; width: 100%; }
  .nav-toggle { display: flex; }
  .nav-cta { margin-left: 0; }

  /* Mobile: language selector compact — globe only */
  .lang-btn { padding: 0 7px; }
  .lang-current { display: none; }
  .lang-arrow { display: none; }
  .lang-menu { right: auto; left: 0; }

  .features-grid { grid-template-columns: 1fr; }
  .api-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: var(--space-8); }

  .hero-title { font-size: clamp(1.8rem, 8vw, 2.8rem); }
  .hero-actions { flex-direction: column; }
  .hero-actions .btn { width: 100%; justify-content: center; }

  .arch-flow { flex-direction: column; }
  .arch-arrow { transform: rotate(90deg); }

  .footer-bottom { flex-direction: column; text-align: center; }
}