/* ============================================
   docFoundry - Styles Principaux
   Tutoriel "Créer son Premier Système FoundryVTT"
   ============================================ */

/* ============================================
   Variables CSS - Thème
   ============================================ */
:root {
  /* Couleurs principales */
  --color-primary: #e8640a;
  --color-primary-light: #ff7a1a;
  --color-primary-dark: #c45000;
  --color-secondary: #1a1a2e;
  --color-secondary-light: #2d2d44;
  --color-accent: #16213e;
  
  /* Thème clair (défaut) */
  --color-bg: #ffffff;
  --color-bg-alt: #f8f9fa;
  --color-bg-code: #f4f4f4;
  --color-text: #2d2d44;
  --color-text-muted: #6c757d;
  --color-text-inverse: #ffffff;
  --color-border: #e0e0e0;
  --color-shadow: rgba(0, 0, 0, 0.1);
  --color-shadow-strong: rgba(0, 0, 0, 0.2);
  
  /* Cards */
  --card-bg: #ffffff;
  --card-border: #e0e0e0;
  --card-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --card-shadow-hover: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
  
  /* Typography */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: "Fira Code", "Consolas", "Monaco", "Andale Mono", monospace;
  
  /* 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: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-full: 9999px;
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 350ms ease;
  
  /* Header */
  --header-height: 70px;
  
  /* Z-index */
  --z-header: 100;
  --z-nav: 90;
  --z-overlay: 80;
}

/* Thème sombre */
[data-theme="dark"] {
  --color-bg: #0f0f1a;
  --color-bg-alt: #1a1a2e;
  --color-bg-code: #1e1e2e;
  --color-text: #e4e4e7;
  --color-text-muted: #a1a1aa;
  --color-border: #2d2d44;
  --color-shadow: rgba(0, 0, 0, 0.3);
  --color-shadow-strong: rgba(0, 0, 0, 0.5);
  
  --card-bg: #1a1a2e;
  --card-border: #2d2d44;
  --card-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
  --card-shadow-hover: 0 20px 25px -5px rgba(0, 0, 0, 0.4);
}

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

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

body {
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  transition: background-color var(--transition-base), color var(--transition-base);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

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

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

ul, ol {
  list-style: none;
}

button {
  font-family: inherit;
  font-size: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

/* ============================================
   Container
   ============================================ */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

/* ============================================
   Header
   ============================================ */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background-color: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  z-index: var(--z-header);
  transition: background-color var(--transition-base), border-color var(--transition-base);
}

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

.header__logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text);
  text-decoration: none;
  flex: 0 0 180px; /* Largeur fixe pour équilibrer avec actions */
}

.header__logo:hover {
  color: var(--color-primary);
}

.header__logo-icon {
  font-size: 1.5rem;
}

.header__actions {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  flex: 0 0 180px; /* Même largeur que le logo pour centrer la nav */
  justify-content: flex-end;
}

/* Navigation - Centrée */
.nav {
  flex: 1;
  display: flex;
  justify-content: center;
}

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

.nav__link {
  color: var(--color-text);
  font-weight: 500;
  padding: var(--spacing-sm) 0;
  position: relative;
}

.nav__link::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--color-primary);
  transition: width var(--transition-base);
}

.nav__link:hover {
  color: var(--color-primary);
}

.nav__link:hover::after {
  width: 100%;
}

/* Theme Toggle */
.theme-toggle {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  background-color: var(--color-bg-alt);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  transition: background-color var(--transition-fast);
}

.theme-toggle:hover {
  background-color: var(--color-border);
}

.theme-toggle__icon--dark {
  display: none;
}

[data-theme="dark"] .theme-toggle__icon--light {
  display: none;
}

[data-theme="dark"] .theme-toggle__icon--dark {
  display: inline;
}

/* Nav Toggle (Mobile) */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  width: 30px;
  height: 24px;
  padding: 0;
}

.nav-toggle__bar {
  display: block;
  width: 100%;
  height: 3px;
  background-color: var(--color-text);
  border-radius: var(--radius-full);
  transition: transform var(--transition-base), opacity var(--transition-base);
}

/* ============================================
   Hero Section
   ============================================ */
.hero {
  padding-top: calc(var(--header-height) + var(--spacing-3xl));
  padding-bottom: var(--spacing-3xl);
  background: linear-gradient(135deg, var(--color-bg) 0%, var(--color-bg-alt) 100%);
  min-height: 90vh;
  display: flex;
  align-items: center;
}

.hero__container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-3xl);
  align-items: center;
}

.hero__title {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: var(--spacing-lg);
}

.hero__title-highlight {
  display: block;
  color: var(--color-primary);
}

.hero__subtitle {
  font-size: 1.25rem;
  color: var(--color-text-muted);
  margin-bottom: var(--spacing-xl);
  max-width: 540px;
}

.hero__cta {
  display: flex;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-xl);
  flex-wrap: wrap;
}

.hero__badges {
  display: flex;
  gap: var(--spacing-sm);
  flex-wrap: wrap;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-md) var(--spacing-xl);
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 1rem;
  transition: all var(--transition-fast);
}

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

.btn--primary:hover {
  background-color: var(--color-primary-light);
  color: var(--color-text-inverse);
  transform: translateY(-2px);
  box-shadow: 0 10px 20px rgba(232, 100, 10, 0.3);
}

.btn--secondary {
  background-color: transparent;
  color: var(--color-text);
  border: 2px solid var(--color-border);
}

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

/* Badge */
.badge {
  display: inline-block;
  padding: var(--spacing-xs) var(--spacing-md);
  background-color: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-muted);
}

/* Hero Code Preview */
.hero__illustration {
  position: relative;
}

.hero__code-preview {
  background-color: #1e1e2e;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--card-shadow-hover);
  transform: perspective(1000px) rotateY(-5deg) rotateX(5deg);
  transition: transform var(--transition-base);
}

.hero__code-preview:hover {
  transform: perspective(1000px) rotateY(0) rotateX(0);
}

.code-header {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-md);
  background-color: #16161e;
}

.code-header__dot {
  width: 12px;
  height: 12px;
  border-radius: var(--radius-full);
}

.code-header__dot--red { background-color: #ff5f56; }
.code-header__dot--yellow { background-color: #ffbd2e; }
.code-header__dot--green { background-color: #27c93f; }

.code-header__title {
  margin-left: auto;
  font-size: 0.75rem;
  color: #6c7086;
  font-family: var(--font-mono);
}

.hero__code {
  margin: 0;
  padding: var(--spacing-lg);
  font-size: 0.875rem;
  line-height: 1.5;
  overflow-x: auto;
}

.hero__code code {
  font-family: var(--font-mono);
}

/* ============================================
   Sections
   ============================================ */
.section {
  padding: var(--spacing-3xl) 0;
}

.section--alt {
  background-color: var(--color-bg-alt);
}

.section__title {
  font-size: 2rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: var(--spacing-md);
}

.section__subtitle {
  text-align: center;
  color: var(--color-text-muted);
  max-width: 600px;
  margin: 0 auto var(--spacing-2xl);
}

/* ============================================
   Introduction Cards
   ============================================ */
.intro-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--spacing-lg);
}

.intro-card {
  text-align: center;
  padding: var(--spacing-xl);
  background-color: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.intro-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--card-shadow-hover);
}

.intro-card__icon {
  font-size: 2.5rem;
  margin-bottom: var(--spacing-md);
}

.intro-card__title {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
}

.intro-card__text {
  color: var(--color-text-muted);
  font-size: 0.9375rem;
}

/* ============================================
   Prerequisites
   ============================================ */
.prereq-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-2xl);
}

.prereq-card {
  background-color: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
}

.prereq-card__header {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
}

.prereq-card__icon {
  font-size: 1.5rem;
}

.prereq-card__title {
  font-size: 1.125rem;
  font-weight: 600;
}

.prereq-card__list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.prereq-card__item {
  display: flex;
  gap: var(--spacing-sm);
  font-size: 0.9375rem;
}

.prereq-card__check {
  color: var(--color-primary);
  font-weight: bold;
}

.prereq-install {
  background-color: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
}

.prereq-install h3 {
  margin-bottom: var(--spacing-lg);
  font-size: 1.125rem;
}

.prereq-install pre {
  margin: 0;
  border-radius: var(--radius-md);
  overflow-x: auto;
}

/* ============================================
   Chapters Grid
   ============================================ */
.chapters-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--spacing-lg);
}

.chapter-card {
  display: flex;
  background-color: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.chapter-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--card-shadow-hover);
}

.chapter-card__number {
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 80px;
  background-color: var(--color-secondary);
  color: var(--color-text-inverse);
  font-size: 1.5rem;
  font-weight: 700;
  font-family: var(--font-mono);
}

.chapter-card__content {
  padding: var(--spacing-lg);
  flex: 1;
}

.chapter-card__badge {
  display: inline-block;
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--radius-sm);
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: var(--spacing-sm);
}

.chapter-card__badge--beginner {
  background-color: #d4edda;
  color: #155724;
}

.chapter-card__badge--intermediate {
  background-color: #fff3cd;
  color: #856404;
}

.chapter-card__badge--advanced {
  background-color: #f8d7da;
  color: #721c24;
}

[data-theme="dark"] .chapter-card__badge--beginner {
  background-color: #1e4620;
  color: #a3d9a5;
}

[data-theme="dark"] .chapter-card__badge--intermediate {
  background-color: #4a4016;
  color: #f0d98d;
}

[data-theme="dark"] .chapter-card__badge--advanced {
  background-color: #4a1c1c;
  color: #f5a5a5;
}

.chapter-card__title {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
}

.chapter-card__desc {
  color: var(--color-text-muted);
  font-size: 0.9375rem;
  margin-bottom: var(--spacing-md);
}

.chapter-card__topics {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-md);
}

.chapter-card__topics li {
  font-size: 0.8125rem;
  padding: var(--spacing-xs) var(--spacing-sm);
  background-color: var(--color-bg-alt);
  border-radius: var(--radius-sm);
  color: var(--color-text-muted);
}

.chapter-card__link {
  font-weight: 600;
  color: var(--color-primary);
  transition: gap var(--transition-fast);
}

.chapter-card__link:hover {
  text-decoration: underline;
}

/* ============================================
   Code Example Section
   ============================================ */
.code-example {
  background-color: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.code-tabs {
  display: flex;
  background-color: var(--color-bg-alt);
  border-bottom: 1px solid var(--card-border);
}

.code-tab {
  padding: var(--spacing-md) var(--spacing-xl);
  font-weight: 500;
  color: var(--color-text-muted);
  border-bottom: 2px solid transparent;
  transition: all var(--transition-fast);
}

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

.code-tab--active {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}

.code-panel {
  display: none;
  padding: 0;
}

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

.code-panel pre {
  margin: 0;
  border-radius: 0;
}

/* ============================================
   Resources Grid
   ============================================ */
.resources-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--spacing-lg);
}

.resource-card {
  display: flex;
  flex-direction: column;
  padding: var(--spacing-xl);
  background-color: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  text-decoration: none;
  color: inherit;
  transition: transform var(--transition-base), box-shadow var(--transition-base), border-color var(--transition-base);
}

.resource-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--card-shadow-hover);
  border-color: var(--color-primary);
  color: inherit;
}

.resource-card__icon {
  font-size: 2rem;
  margin-bottom: var(--spacing-md);
}

.resource-card__title {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
}

.resource-card__desc {
  color: var(--color-text-muted);
  font-size: 0.9375rem;
  flex: 1;
  margin-bottom: var(--spacing-md);
}

.resource-card__link {
  color: var(--color-primary);
  font-weight: 500;
  font-size: 0.875rem;
}

/* ============================================
   Footer
   ============================================ */
.footer {
  background-color: var(--color-secondary);
  color: var(--color-text-inverse);
  padding: var(--spacing-3xl) 0 var(--spacing-xl);
}

.footer__container {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-2xl);
}

.footer__brand {
  text-align: center;
}

.footer__logo {
  font-size: 1.5rem;
  font-weight: 700;
}

.footer__tagline {
  color: rgba(255, 255, 255, 0.7);
  margin-top: var(--spacing-sm);
}

.footer__links {
  display: flex;
  justify-content: center;
  gap: var(--spacing-3xl);
}

.footer__col {
  text-align: center;
}

.footer__heading {
  font-size: 0.875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: var(--spacing-md);
  color: var(--color-primary);
}

.footer__list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.footer__list a {
  color: rgba(255, 255, 255, 0.7);
  font-size: 0.9375rem;
  transition: color var(--transition-fast);
}

.footer__list a:hover {
  color: var(--color-text-inverse);
}

.footer__bottom {
  text-align: center;
  padding-top: var(--spacing-xl);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.footer__copyright {
  color: rgba(255, 255, 255, 0.5);
  font-size: 0.875rem;
}

/* ============================================
   Code Blocks General Styling
   ============================================ */
pre[class*="language-"] {
  background: #1e1e2e !important;
  border-radius: var(--radius-md);
  padding: var(--spacing-lg);
  overflow-x: auto;
  font-size: 0.875rem;
  line-height: 1.6;
}

code[class*="language-"] {
  font-family: var(--font-mono);
}

:not(pre) > code {
  font-family: var(--font-mono);
  background-color: var(--color-bg-code);
  padding: 0.125em 0.375em;
  border-radius: var(--radius-sm);
  font-size: 0.875em;
}

/* ============================================
   Section Contexte IA
   ============================================ */
.ia-context-card {
  display: flex;
  gap: var(--spacing-xl);
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
  box-shadow: var(--card-shadow);
  margin-bottom: var(--spacing-xl);
}

.ia-context-card__icon {
  font-size: 4rem;
  flex-shrink: 0;
}

.ia-context-card__content {
  flex: 1;
}

.ia-context-card__title {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: var(--spacing-sm);
  color: var(--color-text);
}

.ia-context-card__desc {
  color: var(--color-text-muted);
  margin-bottom: var(--spacing-md);
  line-height: 1.7;
}

.ia-context-card__desc code {
  background: var(--color-bg-code);
  padding: 0.15em 0.4em;
  border-radius: var(--radius-sm);
  font-size: 0.9em;
}

.ia-context-card__list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-lg);
}

.ia-context-card__list li {
  color: var(--color-text);
  font-size: 0.95rem;
}

.ia-context-card__btn {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-md) var(--spacing-xl);
  background: var(--color-primary);
  color: white;
  font-weight: 600;
  border-radius: var(--radius-md);
  text-decoration: none;
  transition: background-color var(--transition-fast), transform var(--transition-fast);
}

.ia-context-card__btn:hover {
  background: var(--color-primary-light);
  color: white;
  transform: translateY(-2px);
}

.ia-context-tip {
  background: var(--color-bg-alt);
  border-left: 4px solid var(--color-primary);
  padding: var(--spacing-md) var(--spacing-lg);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  color: var(--color-text);
}

.ia-context-tip code {
  background: var(--color-bg-code);
  padding: 0.15em 0.4em;
  border-radius: var(--radius-sm);
  font-size: 0.9em;
}

/* Responsive */
@media (max-width: 768px) {
  .ia-context-card {
    flex-direction: column;
    text-align: center;
  }
  
  .ia-context-card__list {
    grid-template-columns: 1fr;
    text-align: left;
  }
}

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

/* Tablet */
@media (max-width: 1024px) {
  .hero__container {
    grid-template-columns: 1fr;
    text-align: center;
  }
  
  .hero__subtitle {
    margin-left: auto;
    margin-right: auto;
  }
  
  .hero__cta {
    justify-content: center;
  }
  
  .hero__badges {
    justify-content: center;
  }
  
  .hero__illustration {
    display: none;
  }
  
  .intro-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .prereq-grid {
    grid-template-columns: 1fr;
  }
  
  .chapters-grid {
    grid-template-columns: 1fr;
  }
  
  .resources-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .footer__links {
    flex-wrap: wrap;
    gap: var(--spacing-xl);
  }
}

/* Mobile */
@media (max-width: 768px) {
  .nav {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    bottom: 0;
    background-color: var(--color-bg);
    padding: var(--spacing-xl);
    transform: translateX(100%);
    transition: transform var(--transition-base);
    z-index: var(--z-nav);
  }
  
  .nav--open {
    transform: translateX(0);
  }
  
  .nav__list {
    flex-direction: column;
    gap: var(--spacing-lg);
  }
  
  .nav__link {
    font-size: 1.25rem;
  }
  
  .nav-toggle {
    display: flex;
  }
  
  .nav-toggle--active .nav-toggle__bar:nth-child(1) {
    transform: translateY(8px) rotate(45deg);
  }
  
  .nav-toggle--active .nav-toggle__bar:nth-child(2) {
    opacity: 0;
  }
  
  .nav-toggle--active .nav-toggle__bar:nth-child(3) {
    transform: translateY(-8px) rotate(-45deg);
  }
  
  .hero {
    padding-top: calc(var(--header-height) + var(--spacing-2xl));
    min-height: auto;
  }
  
  .hero__title {
    font-size: 2rem;
  }
  
  .hero__subtitle {
    font-size: 1rem;
  }
  
  .hero__cta {
    flex-direction: column;
  }
  
  .btn {
    width: 100%;
  }
  
  .section {
    padding: var(--spacing-2xl) 0;
  }
  
  .section__title {
    font-size: 1.5rem;
  }
  
  .intro-grid {
    grid-template-columns: 1fr;
  }
  
  .chapter-card {
    flex-direction: column;
  }
  
  .chapter-card__number {
    min-width: auto;
    padding: var(--spacing-md);
    font-size: 1.25rem;
  }
  
  .resources-grid {
    grid-template-columns: 1fr;
  }
  
  .code-tabs {
    overflow-x: auto;
  }
  
  .code-tab {
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 0.875rem;
    white-space: nowrap;
  }
  
  .footer__links {
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xl);
  }
}

/* ============================================
   Animations
   ============================================ */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.hero__content {
  animation: fadeInUp 0.6s ease-out;
}

.hero__illustration {
  animation: fadeInUp 0.6s ease-out 0.2s both;
}

/* Accessibility */
@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;
  }
}

/* Focus visible styles */
:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

button:focus:not(:focus-visible),
a:focus:not(:focus-visible) {
  outline: none;
}

/* Selection */
::selection {
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
}

/* ============================================
   Chapter Pages Styles
   ============================================ */

/* Chapter Content Layout */
.chapter-content {
  padding-top: calc(var(--header-height) + var(--spacing-2xl));
  padding-bottom: var(--spacing-3xl);
  min-height: calc(100vh - 300px);
}

/* Breadcrumb */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-xl);
  font-size: 0.875rem;
  color: var(--color-text-muted);
}

.breadcrumb a {
  color: var(--color-text-muted);
}

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

/* Chapter Article */
.chapter {
  max-width: 800px;
  margin: 0 auto;
}

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

.chapter-number {
  display: inline-block;
  padding: var(--spacing-xs) var(--spacing-md);
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
  border-radius: var(--radius-full);
  font-size: 0.875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: var(--spacing-md);
}

.chapter-header h1 {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 700;
  margin-bottom: var(--spacing-md);
}

.chapter-intro {
  font-size: 1.125rem;
  color: var(--color-text-muted);
  max-width: 600px;
  margin: 0 auto;
}

/* Chapter Sections */
.chapter-section {
  margin-bottom: var(--spacing-3xl);
}

.chapter-section h2 {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: var(--spacing-lg);
  padding-bottom: var(--spacing-sm);
  border-bottom: 2px solid var(--color-primary);
}

.chapter-section h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-top: var(--spacing-xl);
  margin-bottom: var(--spacing-md);
  color: var(--color-text);
}

.chapter-section p {
  margin-bottom: var(--spacing-md);
  line-height: 1.8;
}

.chapter-section ul,
.chapter-section ol {
  margin-bottom: var(--spacing-lg);
  padding-left: var(--spacing-xl);
}

.chapter-section ul {
  list-style-type: disc;
}

.chapter-section ol {
  list-style-type: decimal;
}

.chapter-section li {
  margin-bottom: var(--spacing-sm);
  line-height: 1.7;
}

.chapter-section li strong {
  color: var(--color-text);
}

/* Callouts: Tips and Warnings */
.tip,
.warning,
.info {
  padding: var(--spacing-lg);
  border-radius: var(--radius-md);
  margin: var(--spacing-lg) 0;
  border-left: 4px solid;
}

.tip {
  background-color: rgba(39, 201, 63, 0.1);
  border-color: #27c93f;
}

.tip strong {
  color: #27c93f;
}

.warning {
  background-color: rgba(255, 189, 46, 0.1);
  border-color: #ffbd2e;
}

.warning strong {
  color: #d4a012;
}

.info {
  background-color: rgba(66, 153, 225, 0.1);
  border-color: #4299e1;
}

.info strong {
  color: #4299e1;
}

[data-theme="dark"] .tip {
  background-color: rgba(39, 201, 63, 0.15);
}

[data-theme="dark"] .warning {
  background-color: rgba(255, 189, 46, 0.15);
}

[data-theme="dark"] .info {
  background-color: rgba(66, 153, 225, 0.15);
}

/* Data Tables */
.data-table {
  width: 100%;
  border-collapse: collapse;
  margin: var(--spacing-lg) 0;
  font-size: 0.9375rem;
}

.data-table th,
.data-table td {
  padding: var(--spacing-md);
  text-align: left;
  border-bottom: 1px solid var(--color-border);
}

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

.data-table tr:hover {
  background-color: var(--color-bg-alt);
}

.data-table code {
  font-size: 0.875em;
}

/* Chapter Navigation */
.chapter-nav {
  display: flex;
  justify-content: space-between;
  gap: var(--spacing-lg);
  margin-top: var(--spacing-3xl);
  padding-top: var(--spacing-xl);
  border-top: 1px solid var(--color-border);
}

.chapter-nav a {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-md) var(--spacing-lg);
  background-color: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-md);
  font-weight: 500;
  transition: all var(--transition-fast);
}

.chapter-nav a:hover {
  border-color: var(--color-primary);
  background-color: var(--color-bg-alt);
}

.chapter-nav .prev {
  margin-right: auto;
}

.chapter-nav .next {
  margin-left: auto;
}

/* Exercise Section */
.exercise {
  background-color: var(--color-bg-alt);
  border: 2px dashed var(--color-primary);
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
}

.exercise h2 {
  border-bottom: none;
  color: var(--color-primary);
}

/* Details/Summary (Solutions) */
details {
  margin-top: var(--spacing-lg);
}

details summary {
  cursor: pointer;
  font-weight: 600;
  color: var(--color-primary);
  padding: var(--spacing-sm) 0;
}

details summary:hover {
  text-decoration: underline;
}

details[open] summary {
  margin-bottom: var(--spacing-md);
}

/* Resources List */
.resources-list {
  list-style: none;
  padding: 0;
}

.resources-list li {
  margin-bottom: var(--spacing-md);
}

.resources-list a {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-md);
  background-color: var(--color-bg-alt);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.resources-list a:hover {
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
}

/* Active Nav Link */
.nav__link--active,
.nav__link.active {
  color: var(--color-primary);
}

.nav__link--active::after,
.nav__link.active::after {
  width: 100%;
}

/* Table of Contents (Optional) */
.toc {
  background-color: var(--color-bg-alt);
  border-radius: var(--radius-md);
  padding: var(--spacing-lg);
  margin-bottom: var(--spacing-2xl);
}

.toc h3 {
  margin-bottom: var(--spacing-md);
  font-size: 1rem;
}

.toc ul {
  list-style: none;
  padding-left: 0;
}

.toc li {
  margin-bottom: var(--spacing-xs);
}

.toc a {
  color: var(--color-text-muted);
  font-size: 0.9375rem;
}

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

/* Responsive Chapter */
@media (max-width: 768px) {
  .chapter-content {
    padding-top: calc(var(--header-height) + var(--spacing-lg));
  }
  
  .chapter-header {
    margin-bottom: var(--spacing-2xl);
  }
  
  .chapter-section h2 {
    font-size: 1.25rem;
  }
  
  .chapter-nav {
    flex-direction: column;
  }
  
  .chapter-nav a {
    justify-content: center;
  }
  
  .data-table {
    display: block;
    overflow-x: auto;
  }
}