/* ============================================================
   TANTRA VIDYA — Design System
   Aesthetic: "Sacred Organic" — Dark-first, golden warmth, mystical depth
   ============================================================ */

/* --- Google Fonts --- */
@import url('https://fonts.googleapis.com/css2?family=Cormorant+Garamond:ital,wght@0,400;0,500;0,600;0,700;1,400;1,500&family=Source+Sans+3:ital,wght@0,300;0,400;0,500;0,600;0,700;1,400&family=Noto+Sans+Devanagari:wght@400;500;600;700&display=swap');

/* ============================================================
   1. DESIGN TOKENS
   ============================================================ */
:root {
  /* --- Color Palette (Dark Theme — Primary) --- */
  --color-bg-primary: #0a0a12;
  --color-bg-secondary: #111122;
  --color-bg-tertiary: #1a1a2e;
  --color-bg-card: #16162a;
  --color-bg-card-hover: #1e1e3a;

  --color-gold: #d4a853;
  --color-gold-bright: #f0c860;
  --color-gold-dim: #a07830;
  --color-gold-glow: rgba(212, 168, 83, 0.15);

  --color-indigo: #4a3f8a;
  --color-indigo-bright: #6b5dc7;
  --color-indigo-dim: #2e2560;

  --color-crimson: #b83a3a;
  --color-crimson-bright: #e04848;

  --color-text-primary: #e8e0d0;
  --color-text-secondary: #b0a890;
  --color-text-muted: #787060;
  --color-text-accent: var(--color-gold);

  --color-border: rgba(212, 168, 83, 0.12);
  --color-border-strong: rgba(212, 168, 83, 0.25);
  --color-divider: rgba(212, 168, 83, 0.08);

  --color-link: var(--color-gold);
  --color-link-hover: var(--color-gold-bright);

  /* --- Typography --- */
  --font-display: 'Cormorant Garamond', Georgia, 'Times New Roman', serif;
  --font-body: 'Source Sans 3', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-devanagari: 'Noto Sans Devanagari', sans-serif;

  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-md: 1.125rem;
  --font-size-lg: 1.25rem;
  --font-size-xl: 1.5rem;
  --font-size-2xl: 2rem;
  --font-size-3xl: 2.5rem;
  --font-size-4xl: 3.5rem;
  --font-size-5xl: 5rem;

  --line-height-tight: 1.15;
  --line-height-normal: 1.6;
  --line-height-relaxed: 1.8;

  /* --- Spacing (8px Base) --- */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;
  --space-32: 8rem;

  /* --- Layout --- */
  --max-width: 1200px;
  --max-width-content: 800px;
  --max-width-narrow: 680px;

  /* --- Borders & Radius --- */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-round: 50%;

  /* --- Shadows --- */
  --shadow-sm: 0 1px 3px 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 var(--color-gold-glow);
  --shadow-card: 0 2px 16px rgba(0,0,0,0.4), inset 0 1px 0 rgba(212,168,83,0.05);

  /* --- Transitions --- */
  --transition-fast: 150ms ease;
  --transition-normal: 300ms ease;
  --transition-slow: 500ms cubic-bezier(0.25, 0.46, 0.45, 0.94);

  /* --- Z-Index --- */
  --z-nav: 100;
  --z-overlay: 200;
  --z-modal: 300;
  --z-toast: 400;
}

/* --- Light Theme --- */
[data-theme="light"] {
  --color-bg-primary: #faf5ee;
  --color-bg-secondary: #f0e8d8;
  --color-bg-tertiary: #e8dfc8;
  --color-bg-card: #fff9f0;
  --color-bg-card-hover: #fff4e0;

  --color-text-primary: #1a1408;
  --color-text-secondary: #45401a;
  --color-text-muted: #8a7e60;

  --color-border: rgba(100, 80, 30, 0.15);
  --color-border-strong: rgba(100, 80, 30, 0.3);
  --color-divider: rgba(100, 80, 30, 0.08);

  --shadow-sm: 0 1px 3px rgba(0,0,0,0.1);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.12);
  --shadow-lg: 0 8px 32px rgba(0,0,0,0.15);
  --shadow-card: 0 2px 16px rgba(0,0,0,0.08), inset 0 1px 0 rgba(255,255,255,0.8);
}

/* ============================================================
   2. RESET & BASE
   ============================================================ */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: var(--font-body);
  font-size: var(--font-size-md);
  line-height: var(--line-height-normal);
  color: var(--color-text-primary);
  background-color: var(--color-bg-primary);
  overflow-x: hidden;
  min-height: 100vh;
}

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

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

::selection {
  background-color: var(--color-gold);
  color: var(--color-bg-primary);
}

/* ============================================================
   3. TYPOGRAPHY
   ============================================================ */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: 600;
  line-height: var(--line-height-tight);
  color: var(--color-text-primary);
}

h1 {
  font-size: var(--font-size-4xl);
  font-weight: 700;
  letter-spacing: -0.02em;
}
h2 {
  font-size: var(--font-size-2xl);
  font-weight: 600;
  margin-top: var(--space-16);
  margin-bottom: var(--space-6);
}
h3 {
  font-size: var(--font-size-xl);
  margin-top: var(--space-12);
  margin-bottom: var(--space-4);
}

p {
  margin-bottom: var(--space-6);
}

.sanskrit {
  font-family: var(--font-devanagari);
  font-weight: 500;
}

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

/* ============================================================
   4. LAYOUT
   ============================================================ */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-6);
}
.container--narrow {
  max-width: var(--max-width-narrow);
}
.container--content {
  max-width: var(--max-width-content);
}

.section {
  padding: var(--space-24) 0;
}
.section--alt {
  background-color: var(--color-bg-secondary);
}

.grid {
  display: grid;
  gap: var(--space-8);
}
.grid--2 { grid-template-columns: repeat(2, 1fr); }
.grid--3 { grid-template-columns: repeat(3, 1fr); }
.grid--4 { grid-template-columns: repeat(4, 1fr); }
.grid--5 { grid-template-columns: repeat(5, 1fr); }

.flex {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}
.flex--between { justify-content: space-between; }
.flex--center { justify-content: center; }
.flex--column { flex-direction: column; align-items: stretch; }

/* ============================================================
   5. NAVIGATION
   ============================================================ */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: var(--z-nav);
  background: rgba(10, 10, 18, 0.85);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border-bottom: 1px solid var(--color-border);
  transition: background var(--transition-normal), box-shadow var(--transition-normal);
}
.nav.scrolled {
  background: rgba(10, 10, 18, 0.95);
  box-shadow: 0 4px 30px rgba(0,0,0,0.5);
}

[data-theme="light"] .nav {
  background: rgba(250, 245, 238, 0.85);
}
[data-theme="light"] .nav.scrolled {
  background: rgba(250, 245, 238, 0.95);
  box-shadow: 0 4px 30px rgba(0,0,0,0.1);
}

.nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-6);
}

.nav__logo {
  font-family: var(--font-display);
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--color-gold);
  display: flex;
  align-items: center;
  gap: var(--space-3);
}
.nav__logo-icon {
  width: 36px;
  height: 36px;
  opacity: 0.9;
}

.nav__links {
  display: flex;
  gap: var(--space-2);
  list-style: none;
}
.nav__link {
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  position: relative;
}
.nav__link:hover,
.nav__link.active {
  color: var(--color-gold);
  background: var(--color-gold-glow);
}

.nav__actions {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.nav__theme-toggle {
  width: 40px;
  height: 40px;
  border: none;
  background: transparent;
  color: var(--color-text-secondary);
  cursor: pointer;
  border-radius: var(--radius-round);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--font-size-lg);
  transition: all var(--transition-fast);
}
.nav__theme-toggle:hover {
  color: var(--color-gold);
  background: var(--color-gold-glow);
}

.nav__mobile-toggle {
  display: none;
  width: 40px;
  height: 40px;
  border: none;
  background: transparent;
  color: var(--color-text-primary);
  cursor: pointer;
  font-size: var(--font-size-xl);
}

/* Mobile Nav */
.nav__mobile-menu {
  display: none;
  position: fixed;
  top: 72px;
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--color-bg-primary);
  padding: var(--space-8);
  overflow-y: auto;
  z-index: var(--z-overlay);
}
.nav__mobile-menu.open {
  display: block;
}
.nav__mobile-menu .nav__links {
  flex-direction: column;
  gap: var(--space-2);
}
.nav__mobile-menu .nav__link {
  font-size: var(--font-size-lg);
  padding: var(--space-4);
}

/* ============================================================
   6. HERO SECTION
   ============================================================ */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: var(--space-32) var(--space-6);
  overflow: hidden;
}

.hero__bg {
  position: absolute;
  inset: 0;
  z-index: 0;
}
.hero__bg img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.15;
  filter: blur(1px);
}
.hero__bg::after {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at center, transparent 20%, var(--color-bg-primary) 75%);
}

.hero__content {
  position: relative;
  z-index: 1;
  max-width: 800px;
}

.hero__subtitle {
  font-family: var(--font-display);
  font-size: var(--font-size-lg);
  color: var(--color-gold);
  font-weight: 400;
  letter-spacing: 0.3em;
  text-transform: uppercase;
  margin-bottom: var(--space-6);
  opacity: 0;
  animation: fadeUp 0.8s 0.2s forwards;
}
.hero__subtitle .sanskrit {
  letter-spacing: 0.1em;
}

.hero__title {
  font-size: var(--font-size-5xl);
  font-weight: 700;
  line-height: 1.05;
  margin-bottom: var(--space-8);
  background: linear-gradient(135deg, var(--color-gold-bright), var(--color-gold), var(--color-gold-dim));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  opacity: 0;
  animation: fadeUp 0.8s 0.4s forwards;
}

.hero__description {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  max-width: 600px;
  margin: 0 auto var(--space-12);
  line-height: var(--line-height-relaxed);
  opacity: 0;
  animation: fadeUp 0.8s 0.6s forwards;
}

.hero__cta-group {
  display: flex;
  gap: var(--space-4);
  justify-content: center;
  flex-wrap: wrap;
  opacity: 0;
  animation: fadeUp 0.8s 0.8s forwards;
}

.hero__scroll-hint {
  position: absolute;
  bottom: var(--space-10);
  left: 50%;
  transform: translateX(-50%);
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-2);
  opacity: 0;
  animation: fadeUp 0.8s 1s forwards;
}
.hero__scroll-hint .arrow {
  animation: bounce 2s infinite;
}

/* ============================================================
   7. BUTTONS
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-4) var(--space-8);
  font-family: var(--font-body);
  font-size: var(--font-size-base);
  font-weight: 600;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-normal);
  text-decoration: none;
}

.btn--primary {
  background: linear-gradient(135deg, var(--color-gold), var(--color-gold-dim));
  color: var(--color-bg-primary);
}
.btn--primary:hover {
  background: linear-gradient(135deg, var(--color-gold-bright), var(--color-gold));
  color: var(--color-bg-primary);
  box-shadow: 0 4px 20px rgba(212, 168, 83, 0.3);
  transform: translateY(-2px);
}

.btn--secondary {
  background: transparent;
  color: var(--color-gold);
  border: 1px solid var(--color-border-strong);
}
.btn--secondary:hover {
  background: var(--color-gold-glow);
  color: var(--color-gold-bright);
  border-color: var(--color-gold);
}

.btn--sm {
  padding: var(--space-2) var(--space-5);
  font-size: var(--font-size-sm);
}

/* ============================================================
   8. CHAPTER CARDS
   ============================================================ */
.chapter-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: var(--space-8);
  margin-top: var(--space-10);
}

.chapter-card {
  position: relative;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-8);
  transition: all var(--transition-normal);
  cursor: pointer;
  text-decoration: none;
  display: block;
  overflow: hidden;
}
.chapter-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--color-gold-dim), var(--color-gold), var(--color-gold-dim));
  opacity: 0;
  transition: opacity var(--transition-normal);
}
.chapter-card:hover {
  background: var(--color-bg-card-hover);
  border-color: var(--color-border-strong);
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg), var(--shadow-glow);
}
.chapter-card:hover::before {
  opacity: 1;
}

.chapter-card__number {
  font-family: var(--font-display);
  font-size: var(--font-size-3xl);
  font-weight: 700;
  color: var(--color-gold);
  opacity: 0.2;
  position: absolute;
  top: var(--space-4);
  right: var(--space-6);
}

.chapter-card__icon {
  font-size: var(--font-size-2xl);
  margin-bottom: var(--space-4);
}

.chapter-card__title {
  font-family: var(--font-display);
  font-size: var(--font-size-xl);
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: var(--space-3);
}
.chapter-card__sanskrit {
  font-family: var(--font-devanagari);
  font-size: var(--font-size-sm);
  color: var(--color-gold);
  margin-bottom: var(--space-4);
}
.chapter-card__desc {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
}

/* ============================================================
   9. SECTION TITLES
   ============================================================ */
.section-header {
  text-align: center;
  max-width: 700px;
  margin: 0 auto var(--space-16);
}
.section-header__label {
  font-family: var(--font-display);
  font-size: var(--font-size-sm);
  color: var(--color-gold);
  letter-spacing: 0.25em;
  text-transform: uppercase;
  font-weight: 500;
  margin-bottom: var(--space-4);
}
.section-header__title {
  font-size: var(--font-size-3xl);
  margin-bottom: var(--space-6);
  margin-top: 0;
}
.section-header__desc {
  color: var(--color-text-secondary);
  font-size: var(--font-size-md);
  line-height: var(--line-height-relaxed);
}

/* ============================================================
   10. DECORATIVE DIVIDER
   ============================================================ */
.divider {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-4);
  margin: var(--space-16) 0;
  color: var(--color-gold);
  opacity: 0.4;
}
.divider::before,
.divider::after {
  content: '';
  flex: 1;
  max-width: 120px;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--color-gold), transparent);
}
.divider__icon {
  font-size: var(--font-size-lg);
}

/* ============================================================
   11. BLOCKQUOTE (Sanskrit Slokas)
   ============================================================ */
blockquote {
  position: relative;
  border-left: 3px solid var(--color-gold);
  padding: var(--space-6) var(--space-8);
  margin: var(--space-8) 0;
  background: var(--color-gold-glow);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  font-family: var(--font-display);
  font-size: var(--font-size-lg);
  font-style: italic;
  color: var(--color-text-primary);
  line-height: var(--line-height-relaxed);
}  

/* ============================================================
   12. TABLES
   ============================================================ */
.table-wrapper {
  overflow-x: auto;
  margin: var(--space-8) 0;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
}
table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--font-size-sm);
}
thead {
  background: var(--color-bg-tertiary);
}
th {
  font-weight: 600;
  text-align: left;
  padding: var(--space-4) var(--space-5);
  color: var(--color-gold);
  border-bottom: 1px solid var(--color-border-strong);
  font-size: var(--font-size-xs);
  letter-spacing: 0.05em;
  text-transform: uppercase;
}
td {
  padding: var(--space-4) var(--space-5);
  border-bottom: 1px solid var(--color-divider);
  color: var(--color-text-secondary);
}
tbody tr:hover {
  background: var(--color-gold-glow);
}

/* ============================================================
   13. FOOTER
   ============================================================ */
.footer {
  background: var(--color-bg-secondary);
  border-top: 1px solid var(--color-border);
  padding: var(--space-20) 0 var(--space-10);
}
.footer__grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--space-12);
  margin-bottom: var(--space-16);
}
.footer__brand {
  font-family: var(--font-display);
  font-size: var(--font-size-xl);
  color: var(--color-gold);
  font-weight: 700;
}
.footer__desc {
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
  margin-top: var(--space-4);
  line-height: var(--line-height-relaxed);
}
.footer__heading {
  font-family: var(--font-display);
  color: var(--color-text-primary);
  font-size: var(--font-size-base);
  font-weight: 600;
  margin-bottom: var(--space-5);
}
.footer__links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}
.footer__links a {
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
  transition: color var(--transition-fast);
}
.footer__links a:hover {
  color: var(--color-gold);
}
.footer__bottom {
  border-top: 1px solid var(--color-border);
  padding-top: var(--space-8);
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: var(--color-text-muted);
  font-size: var(--font-size-xs);
}

/* ============================================================
   14. ANIMATIONS
   ============================================================ */
@keyframes fadeUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes bounce {
  0%, 20%, 50%, 80%, 100% { transform: translateY(0); }
  40% { transform: translateY(8px); }
  60% { transform: translateY(4px); }
}

@keyframes pulse-glow {
  0%, 100% { box-shadow: 0 0 20px var(--color-gold-glow); }
  50% { box-shadow: 0 0 40px rgba(212, 168, 83, 0.3); }
}

@keyframes shimmer {
  0% { background-position: -200% 0; }
  100% { background-position: 200% 0; }
}

/* Scroll-triggered animations */
.reveal {
  opacity: 0;
  transform: translateY(40px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}
.reveal--delay-1 { transition-delay: 0.1s; }
.reveal--delay-2 { transition-delay: 0.2s; }
.reveal--delay-3 { transition-delay: 0.3s; }
.reveal--delay-4 { transition-delay: 0.4s; }

/* ============================================================
   15. PROGRESS BAR (Reading Progress)
   ============================================================ */
.progress-bar {
  position: fixed;
  top: 0;
  left: 0;
  width: 0%;
  height: 3px;
  background: linear-gradient(90deg, var(--color-gold-dim), var(--color-gold), var(--color-gold-bright));
  z-index: calc(var(--z-nav) + 1);
  transition: width 50ms linear;
}

/* ============================================================
   16. BADGE / TAG
   ============================================================ */
.badge {
  display: inline-block;
  padding: var(--space-1) var(--space-3);
  font-size: var(--font-size-xs);
  font-weight: 600;
  letter-spacing: 0.05em;
  border-radius: var(--radius-sm);
  background: var(--color-gold-glow);
  color: var(--color-gold);
  border: 1px solid var(--color-border-strong);
}

/* ============================================================
   17. PRINCIPLE CARDS (Key Concepts)
   ============================================================ */
.principle-card {
  padding: var(--space-10);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  background: var(--color-bg-card);
  text-align: center;
  transition: all var(--transition-normal);
}
.principle-card:hover {
  border-color: var(--color-border-strong);
  box-shadow: var(--shadow-glow);
}
.principle-card__icon {
  font-size: 2.5rem;
  margin-bottom: var(--space-5);
}
.principle-card__title {
  font-family: var(--font-display);
  font-size: var(--font-size-lg);
  font-weight: 600;
  margin-bottom: var(--space-3);
}
.principle-card__desc {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
}

/* ============================================================
   18. RESPONSIVE
   ============================================================ */
@media (max-width: 1024px) {
  .grid--3 { grid-template-columns: repeat(2, 1fr); }
  .grid--4 { grid-template-columns: repeat(2, 1fr); }
  .grid--5 { grid-template-columns: repeat(2, 1fr); }
  .footer__grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 768px) {
  html { font-size: 15px; }

  h1 { font-size: var(--font-size-3xl); }
  .hero__title { font-size: var(--font-size-3xl); }
  .section-header__title { font-size: var(--font-size-2xl); }

  .nav__links { display: none; }
  .nav__mobile-toggle { display: flex; align-items: center; justify-content: center; }

  .grid--2,
  .grid--3,
  .grid--4,
  .grid--5 { grid-template-columns: 1fr; }

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

  .hero { min-height: 90vh; padding: var(--space-24) var(--space-5); }
  .hero__cta-group { flex-direction: column; }

  .footer__grid { grid-template-columns: 1fr; gap: var(--space-8); }
  .footer__bottom { flex-direction: column; gap: var(--space-4); text-align: center; }

  .section { padding: var(--space-16) 0; }
}

@media (max-width: 480px) {
  h1 { font-size: var(--font-size-2xl); }
  .hero__title { font-size: var(--font-size-2xl); }
  .hero__subtitle { font-size: var(--font-size-sm); }
}

/* ============================================================
   19. PRINT STYLES
   ============================================================ */
@media print {
  .nav, .footer, .btn, .nav__theme-toggle, .progress-bar { display: none; }
  body { background: #fff; color: #000; font-size: 12pt; }
  a { color: #000; text-decoration: underline; }
  h1, h2, h3 { page-break-after: avoid; }
  .chapter-card { break-inside: avoid; border: 1px solid #ccc; }
}

/* ============================================================
   20. REDUCED MOTION
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; }
}