/* ========================================
   CSS Variables & Reset
   ======================================== */

/* ----- Dark Theme (default) ----- */
:root,
[data-theme="dark"] {
  --color-bg: #000000;
  --color-surface: #0d0d0d;
  --color-surface-raised: #141414;
  --color-surface-hover: #1a1a1a;
  --color-border: rgba(255, 255, 255, 0.08);
  --color-border-hover: rgba(255, 255, 255, 0.14);
  --color-border-strong: rgba(255, 255, 255, 0.1);
  --color-text: #f5f5f7;
  --color-text-secondary: #a1a1aa;
  --color-text-muted: #71717a;
  --color-primary: #10a37f;
  --color-primary-hover: #0ec28b;
  --color-primary-dim: rgba(16, 163, 127, 0.12);
  --color-primary-glow: rgba(16, 163, 127, 0.2);

  --color-card-codex-bg: rgba(16, 163, 127, 0.03);
  --color-card-codex-border: rgba(16, 163, 127, 0.12);
  --color-card-codex-glow: rgba(16, 163, 127, 0.06);
  --color-card-claude-bg: rgba(217, 119, 6, 0.03);
  --color-card-claude-border: rgba(217, 119, 6, 0.12);
  --color-card-claude-glow: rgba(217, 119, 6, 0.05);
  --color-card-ccswitch-bg: rgba(59, 130, 246, 0.03);
  --color-card-ccswitch-border: rgba(59, 130, 246, 0.12);
  --color-card-ccswitch-glow: rgba(59, 130, 246, 0.05);

  --dot-color: rgba(255, 255, 255, 0.06);
  --header-bg: rgba(0, 0, 0, 0.75);
  --btn-primary-bg: #fff;
  --btn-primary-color: #000;
  --btn-primary-hover-bg: #e5e5e5;
  --btn-download-bg: rgba(255, 255, 255, 0.04);
  --btn-download-hover-bg: rgba(255, 255, 255, 0.07);
  --toast-bg: rgba(26, 26, 26, 0.95);
  --canvas-grid: rgba(255, 255, 255, 0.025);
}

/* ----- Light Theme ----- */
[data-theme="light"] {
  --color-bg: #f5f5f7;
  --color-surface: #ffffff;
  --color-surface-raised: #fafafa;
  --color-surface-hover: #f0f0f2;
  --color-border: rgba(0, 0, 0, 0.06);
  --color-border-hover: rgba(0, 0, 0, 0.12);
  --color-border-strong: rgba(0, 0, 0, 0.1);
  --color-text: #1d1d1f;
  --color-text-secondary: #6e6e73;
  --color-text-muted: #999;
  --color-primary: #10a37f;
  --color-primary-hover: #0d8c6a;
  --color-primary-dim: rgba(16, 163, 127, 0.1);
  --color-primary-glow: rgba(16, 163, 127, 0.15);

  --color-card-codex-bg: rgba(16, 163, 127, 0.04);
  --color-card-codex-border: rgba(16, 163, 127, 0.15);
  --color-card-codex-glow: rgba(16, 163, 127, 0.08);
  --color-card-claude-bg: rgba(217, 119, 6, 0.04);
  --color-card-claude-border: rgba(217, 119, 6, 0.15);
  --color-card-claude-glow: rgba(217, 119, 6, 0.07);
  --color-card-ccswitch-bg: rgba(59, 130, 246, 0.04);
  --color-card-ccswitch-border: rgba(59, 130, 246, 0.15);
  --color-card-ccswitch-glow: rgba(59, 130, 246, 0.07);

  --dot-color: rgba(0, 0, 0, 0.06);
  --header-bg: rgba(245, 245, 247, 0.75);
  --btn-primary-bg: #1d1d1f;
  --btn-primary-color: #fff;
  --btn-primary-hover-bg: #333;
  --btn-download-bg: rgba(0, 0, 0, 0.04);
  --btn-download-hover-bg: rgba(0, 0, 0, 0.07);
  --toast-bg: rgba(255, 255, 255, 0.95);
  --canvas-grid: rgba(0, 0, 0, 0.04);
}

:root {
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-xl: 28px;

  --font-sans: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;

  --gutter: 24px;
  --container-max: 1120px;

  --transition-fast: 180ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 300ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 500ms cubic-bezier(0.4, 0, 0.2, 1);

  --header-h: 60px;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 24px);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

/* Subtle dot grid background */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background-image: radial-gradient(circle, var(--dot-color) 1px, transparent 1px);
  background-size: 40px 40px;
  mask-image: linear-gradient(to bottom, transparent 0%, black 10%, black 90%, transparent 100%);
  -webkit-mask-image: linear-gradient(to bottom, transparent 0%, black 10%, black 90%, transparent 100%);
}

a { color: inherit; text-decoration: none; }
ul { list-style: none; }
img { display: block; max-width: 100%; }

.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--gutter);
  position: relative;
  z-index: 1;
}

/* ========================================
   Section Header
   ======================================== */

.section-header {
  text-align: center;
  margin-bottom: 64px;
}

.section-title {
  font-size: clamp(26px, 3.5vw, 38px);
  font-weight: 700;
  letter-spacing: -0.025em;
  line-height: 1.15;
  margin-bottom: 14px;
  color: var(--color-text);
}

.section-subtitle {
  font-size: 16px;
  color: var(--color-text-secondary);
  max-width: 500px;
  margin: 0 auto;
  line-height: 1.6;
}

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

.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  height: var(--header-h);
  transition: background var(--transition-base), border-color var(--transition-base);
  border-bottom: 1px solid transparent;
}

.header.scrolled {
  background: var(--header-bg);
  backdrop-filter: saturate(180%) blur(24px);
  -webkit-backdrop-filter: saturate(180%) blur(24px);
  border-bottom-color: var(--color-border);
}

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

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 17px;
  color: #fff;
  z-index: 1;
}

.logo img { transition: transform var(--transition-base), opacity var(--transition-base); }
.logo:hover img { transform: scale(1.05); opacity: 0.85; }

.nav-list { display: flex; gap: 36px; }

.nav-link {
  font-size: 13.5px;
  font-weight: 500;
  color: var(--color-text-secondary);
  transition: color var(--transition-fast);
  padding: 6px 0;
  letter-spacing: 0.01em;
}

.nav-link:hover { color: var(--color-text); }

/* Header controls group */
.header-controls {
  display: flex;
  align-items: center;
  gap: 4px;
  z-index: 1;
}

.theme-toggle,
.lang-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 10px;
  border: 1px solid var(--color-border);
  background: transparent;
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
  font-size: 12px;
  font-weight: 600;
  font-family: inherit;
  letter-spacing: 0.02em;
}

.theme-toggle:hover,
.lang-toggle:hover {
  color: var(--color-text);
  border-color: var(--color-border-hover);
  background: var(--color-surface-hover);
}

.theme-toggle svg,
.lang-toggle svg {
  width: 18px;
  height: 18px;
}

/* Mobile menu toggle */
.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
  z-index: 1;
}

.menu-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-text);
  border-radius: 1px;
  transition: transform var(--transition-base), opacity var(--transition-base);
}

/* ========================================
   Hero
   ======================================== */

.hero {
  position: relative;
  padding: 160px 0 100px;
  text-align: center;
  overflow: hidden;
  background: #000; /* always dark behind canvas particles */
  isolation: isolate;
}

/* Force hero section to have a dark background behind canvas */
.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  z-index: -1;
  background: #000;
  pointer-events: none;
}

#heroCanvas {
  position: absolute;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  width: 100%;
  height: 100%;
  display: block;
}

.hero .container {
  position: relative;
  z-index: 2;
}

.hero-bg {
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  opacity: 0.7;
}

/* Large soft gradient orbs */
.hero-bg::before {
  content: '';
  position: absolute;
  top: -20%;
  left: 50%;
  transform: translateX(-50%);
  width: 900px;
  height: 600px;
  background: radial-gradient(ellipse 50% 50% at 50% 0%, rgba(16, 163, 127, 0.15) 0%, transparent 60%);
  pointer-events: none;
}

.hero-bg::after {
  content: '';
  position: absolute;
  top: 25%;
  right: 5%;
  width: 500px;
  height: 400px;
  background: radial-gradient(ellipse 50% 50% at 50% 50%, rgba(99, 102, 241, 0.12) 0%, transparent 60%);
  pointer-events: none;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 7px 18px;
  background: rgba(255,255,255,0.06); /* subtle light badge */
  color: #a1a1aa; /* always light on dark hero bg */
  border: 1px solid rgba(255,255,255,0.1);
  border-radius: 100px;
  font-size: 13px;
  font-weight: 500;
  margin-bottom: 28px;
  letter-spacing: 0.01em;
  backdrop-filter: blur(8px);
  transition: background var(--transition-base), border-color var(--transition-base);
}

.hero-badge svg {
  color: var(--color-primary);
  opacity: 0.8;
}

.hero-title {
  font-size: clamp(44px, 7.5vw, 76px);
  font-weight: 800;
  letter-spacing: -0.035em;
  line-height: 1.08;
  margin-bottom: 24px;
  color: #fff; /* always white on dark hero bg */
}

.hero-title .highlight {
  background: linear-gradient(135deg, var(--color-primary) 0%, #3b82f6 60%, #8b5cf6 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: 17px;
  color: #a1a1aa; /* always light gray on dark hero bg */
  line-height: 1.7;
  margin-bottom: 40px;
  font-weight: 400;
}

.hero-actions {
  display: flex;
  gap: 14px;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 64px;
}

.hero-stats {
  display: flex;
  justify-content: center;
  gap: 56px;
  flex-wrap: wrap;
}

.stat { text-align: center; }

.stat-number {
  display: block;
  font-size: 32px;
  font-weight: 800;
  color: #fff; /* always white on dark hero bg */
  letter-spacing: -0.02em;
  margin-bottom: 4px;
}

.stat-label {
  font-size: 13px;
  color: #a1a1aa; /* always light gray on dark hero bg */
  font-weight: 500;
  letter-spacing: 0.02em;
}

/* ========================================
   Buttons
   ======================================== */

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 32px;
  border-radius: 100px;
  font-size: 15px;
  font-weight: 600;
  font-family: inherit;
  border: none;
  cursor: pointer;
  transition: all var(--transition-base);
  position: relative;
  letter-spacing: 0.01em;
}

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

.btn-primary:hover {
  background: var(--btn-primary-hover-bg);
  transform: translateY(-1px);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.15);
}

.btn-primary:active {
  transform: scale(0.97);
  transition: transform 0.1s ease;
}

.btn-secondary {
  background: transparent;
  color: #a1a1aa;
  border: 1px solid rgba(255,255,255,0.12);
}

.btn-secondary:hover {
  background: var(--color-surface-hover);
  border-color: var(--color-border-hover);
}

.btn-download {
  width: 100%;
  justify-content: center;
  padding: 14px 20px;
  background: var(--btn-download-bg);
  color: var(--color-text);
  border: 1px solid var(--color-border);
  font-size: 14px;
  font-weight: 600;
  border-radius: var(--radius-md);
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
}

.btn-download::after {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at center, rgba(127, 127, 127, 0.06) 0%, transparent 70%);
  opacity: 0;
  transition: opacity var(--transition-base);
}

.btn-download:hover {
  background: var(--btn-download-hover-bg);
  border-color: var(--color-border-hover);
  transform: translateY(-1px);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.15);
}

.btn-download:hover::after { opacity: 1; }

.btn-download:active {
  transform: scale(0.98);
  transition: transform 0.1s ease;
}

.btn-icon {
  display: flex;
  align-items: center;
  opacity: 0.6;
}

/* ========================================
   Download Cards
   ======================================== */

.downloads {
  padding: 100px 0 100px;
  position: relative;
}

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

.card {
  position: relative;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  overflow: hidden;
  transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Brand-colored card backgrounds */
.card-codex {
  background: var(--color-card-codex-bg);
  border-color: var(--color-card-codex-border);
}
.card-claude {
  background: var(--color-card-claude-bg);
  border-color: var(--color-card-claude-border);
}
.card-ccswitch {
  background: var(--color-card-ccswitch-bg);
  border-color: var(--color-card-ccswitch-border);
}

.card:hover {
  transform: translateY(-6px);
  box-shadow: 0 24px 64px rgba(0, 0, 0, 0.2);
}

.card-codex:hover {
  border-color: rgba(16, 163, 127, 0.25);
  box-shadow: 0 24px 64px rgba(0, 0, 0, 0.2), 0 0 0 1px rgba(16, 163, 127, 0.08);
}
.card-claude:hover {
  border-color: rgba(217, 119, 6, 0.25);
  box-shadow: 0 24px 64px rgba(0, 0, 0, 0.2), 0 0 0 1px rgba(217, 119, 6, 0.08);
}
.card-ccswitch:hover {
  border-color: rgba(59, 130, 246, 0.25);
  box-shadow: 0 24px 64px rgba(0, 0, 0, 0.2), 0 0 0 1px rgba(59, 130, 246, 0.08);
}

.card-glow {
  position: absolute;
  top: -1px;
  left: 50%;
  transform: translateX(-50%);
  width: 280px;
  height: 1px;
  opacity: 0;
  transition: opacity 0.5s ease;
}

.card-codex .card-glow { background: linear-gradient(90deg, transparent, rgba(16, 163, 127, 0.6), transparent); }
.card-claude .card-glow { background: linear-gradient(90deg, transparent, rgba(217, 119, 6, 0.5), transparent); }
.card-ccswitch .card-glow { background: linear-gradient(90deg, transparent, rgba(59, 130, 246, 0.5), transparent); }

.card:hover .card-glow { opacity: 1; }

/* Inner ambient glow per card */
.card-codex .card-content::before {
  content: '';
  position: absolute;
  top: -60px;
  right: -40px;
  width: 180px;
  height: 180px;
  background: radial-gradient(circle, var(--color-card-codex-glow) 0%, transparent 70%);
  pointer-events: none;
  transition: opacity 0.4s ease;
  opacity: 0.6;
}
.card-codex:hover .card-content::before { opacity: 1; }

.card-claude .card-content::before {
  content: '';
  position: absolute;
  top: -60px;
  right: -40px;
  width: 180px;
  height: 180px;
  background: radial-gradient(circle, var(--color-card-claude-glow) 0%, transparent 70%);
  pointer-events: none;
  transition: opacity 0.4s ease;
  opacity: 0.6;
}
.card-claude:hover .card-content::before { opacity: 1; }

.card-ccswitch .card-content::before {
  content: '';
  position: absolute;
  top: -60px;
  right: -40px;
  width: 180px;
  height: 180px;
  background: radial-gradient(circle, var(--color-card-ccswitch-glow) 0%, transparent 70%);
  pointer-events: none;
  transition: opacity 0.4s ease;
  opacity: 0.6;
}
.card-ccswitch:hover .card-content::before { opacity: 1; }

.card-content {
  padding: 40px 30px;
  display: flex;
  flex-direction: column;
  gap: 18px;
  height: 100%;
  position: relative;
}

.card-icon {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  transition: transform 0.3s ease, background 0.3s ease;
}

.card:hover .card-icon {
  transform: scale(1.05);
  background: var(--color-surface-hover);
}

.card-icon img {
  width: 44px;
  height: 44px;
}

.card-title {
  font-size: 24px;
  font-weight: 750;
  letter-spacing: -0.02em;
  color: var(--color-text);
}

.card-desc {
  font-size: 14px;
  color: var(--color-text-secondary);
  line-height: 1.7;
  flex: 1;
}

.card-platforms {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.platform-tag {
  padding: 4px 12px;
  border-radius: 100px;
  font-size: 11px;
  font-weight: 600;
  background: var(--color-surface);
  color: var(--color-text-muted);
  border: 1px solid var(--color-border);
  letter-spacing: 0.02em;
}

.card-version {
  font-size: 12px;
  color: var(--color-text-muted);
  font-weight: 500;
}

.card-buttons {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.card-note {
  font-size: 11.5px;
  color: var(--color-text-muted);
  text-align: center;
  opacity: 0.6;
}

/* ========================================
   Guide
   ======================================== */

.guide {
  padding: 100px 0;
  border-top: 1px solid var(--color-border);
}

.steps {
  display: flex;
  align-items: flex-start;
  justify-content: center;
  gap: 0;
  max-width: 860px;
  margin: 0 auto;
}

.step {
  flex: 1;
  text-align: center;
  padding: 0 24px;
}

.step-number {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--color-primary);
  margin-bottom: 20px;
  opacity: 0.7;
}

.step-icon {
  width: 68px;
  height: 68px;
  border-radius: 20px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 20px;
  color: var(--color-text-secondary);
  transition: all 0.3s ease;
}

.step:hover .step-icon {
  border-color: rgba(16, 163, 127, 0.2);
  background: var(--color-primary-dim);
  color: var(--color-primary);
}

.step-title {
  font-size: 17px;
  font-weight: 700;
  margin-bottom: 8px;
  color: var(--color-text);
  letter-spacing: -0.01em;
}

.step-desc {
  font-size: 14px;
  color: var(--color-text-secondary);
  line-height: 1.7;
}

.step-divider {
  width: 56px;
  height: 1.5px;
  background: linear-gradient(90deg, transparent, var(--color-border), transparent);
  margin-top: 34px;
  flex-shrink: 0;
}

/* ========================================
   FAQ
   ======================================== */

.faq {
  padding: 100px 0;
  border-top: 1px solid var(--color-border);
}

.faq-list {
  max-width: 700px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.faq-item {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  transition: all var(--transition-base);
}

.faq-item:hover {
  border-color: var(--color-border-hover);
  background: var(--color-surface-raised);
}

.faq-item[open] {
  border-color: rgba(16, 163, 127, 0.18);
  background: var(--color-surface-raised);
}

.faq-question {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 20px 26px;
  cursor: pointer;
  font-size: 15px;
  font-weight: 600;
  list-style: none;
  color: var(--color-text);
}

.faq-question::-webkit-details-marker { display: none; }
.faq-question::marker { display: none; content: ''; }

.faq-chevron {
  display: flex;
  flex-shrink: 0;
  color: var(--color-text-muted);
  transition: transform var(--transition-base);
}

.faq-item[open] .faq-chevron { transform: rotate(180deg); color: var(--color-primary); }

.faq-answer {
  padding: 0 26px 20px;
  font-size: 14px;
  color: var(--color-text-secondary);
  line-height: 1.8;
}

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

.footer {
  border-top: 1px solid var(--color-border);
  padding: 56px 0 36px;
}

.footer-main {
  text-align: center;
  margin-bottom: 28px;
}

.footer-brand {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  font-weight: 700;
  font-size: 16px;
  margin-bottom: 10px;
  color: var(--color-text);
}

.footer-brand img { opacity: 0.8; }

.footer-desc {
  font-size: 14px;
  color: var(--color-text-secondary);
}

.footer-disclaimer {
  text-align: center;
  margin-bottom: 28px;
  padding: 18px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
}

.footer-disclaimer p {
  font-size: 12px;
  color: var(--color-text-muted);
  line-height: 1.9;
}

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

.footer-bottom p {
  font-size: 12px;
  color: var(--color-text-muted);
}

/* ========================================
   Toast
   ======================================== */

.toast {
  position: fixed;
  bottom: 36px;
  left: 50%;
  transform: translateX(-50%) translateY(16px);
  padding: 14px 28px;
  border-radius: 100px;
  font-size: 14px;
  font-weight: 500;
  color: var(--color-text);
  background: var(--toast-bg);
  border: 1px solid var(--color-border-strong);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.2);
  z-index: 200;
  opacity: 0;
  transition: opacity 0.3s ease, transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  pointer-events: none;
}

.toast-visible {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

.toast-success { border-color: rgba(16, 163, 127, 0.25); }
.toast-info { border-color: rgba(99, 102, 241, 0.2); }

/* ========================================
   Animations
   ======================================== */

.fade-in {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.75s cubic-bezier(0.4, 0, 0.2, 1),
              transform 0.75s cubic-bezier(0.4, 0, 0.2, 1);
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Stagger card reveals */
.cards .card:nth-child(2) { transition-delay: 0.08s; }
.cards .card:nth-child(3) { transition-delay: 0.16s; }

.steps .step:nth-child(1) { transition-delay: 0s; }
.steps .step:nth-child(3) { transition-delay: 0.08s; }
.steps .step:nth-child(5) { transition-delay: 0.16s; }

.faq-list .faq-item:nth-child(1) { transition-delay: 0s; }
.faq-list .faq-item:nth-child(2) { transition-delay: 0.04s; }
.faq-list .faq-item:nth-child(3) { transition-delay: 0.08s; }
.faq-list .faq-item:nth-child(4) { transition-delay: 0.12s; }
.faq-list .faq-item:nth-child(5) { transition-delay: 0.16s; }

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

@media (max-width: 1024px) {
  .cards {
    grid-template-columns: repeat(2, 1fr);
  }

  .steps {
    flex-direction: column;
    align-items: center;
    gap: 0;
  }

  .step-divider {
    width: 1.5px;
    height: 48px;
    margin: 0;
  }

  .hero-stats { gap: 40px; }
}

@media (max-width: 768px) {
  .cards {
    grid-template-columns: 1fr;
    max-width: 420px;
    margin: 0 auto;
  }

  .nav {
    position: fixed;
    top: var(--header-h);
    left: 0;
    right: 0;
    background: var(--header-bg);
    backdrop-filter: saturate(180%) blur(24px);
    -webkit-backdrop-filter: saturate(180%) blur(24px);
    border-bottom: 1px solid var(--color-border);
    padding: 24px 0;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-12px);
    transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  }

  .nav.open {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }

  .nav-list {
    flex-direction: column;
    align-items: center;
    gap: 2px;
  }

  .nav-link { display: block; padding: 14px 24px; font-size: 16px; }

  .menu-toggle { display: flex; }

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

  .hero { padding: 120px 0 72px; }

  .hero-stats { gap: 32px; }
  .stat-number { font-size: 26px; }

  .section-header { margin-bottom: 44px; }

  .card-content { padding: 32px 24px; }
}