/* ========================================
   CHAPTER LAYOUTS
   ======================================== */

/* --- Main Content Area --- */
.main-content {
  margin-left: var(--sidebar-width);
  padding-top: calc(var(--nav-height) + 3px);
  min-height: 100vh;
}

/* --- Hero Section --- */
.hero-section {
  min-height: calc(100vh - var(--nav-height));
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: var(--space-16) var(--space-6);
  position: relative;
  overflow: hidden;
}

.hero-section::before {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--gradient-hero);
  z-index: 0;
}

.hero-section > * {
  position: relative;
  z-index: 1;
}

.hero-badge {
  margin-bottom: var(--space-6);
}

.hero-title {
  margin-bottom: var(--space-6);
  max-width: 800px;
}

.hero-subtitle {
  font-size: var(--fs-xl);
  color: var(--text-secondary);
  max-width: 600px;
  margin-bottom: var(--space-10);
}

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

.hero-stats {
  display: flex;
  gap: var(--space-12);
  margin-top: var(--space-16);
}

.hero-stat {
  text-align: center;
}

.hero-stat .stat-value {
  font-size: var(--fs-3xl);
  font-weight: 800;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-stat .stat-label {
  font-size: var(--fs-sm);
  color: var(--text-muted);
  margin-top: var(--space-1);
}

/* --- Particle Background --- */
#particle-canvas {
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
}

/* --- Chapter Section --- */
.chapter-section {
  padding: var(--space-20) var(--space-6);
  position: relative;
}

.chapter-section:nth-child(even) {
  background: var(--bg-secondary);
}

.chapter-header {
  margin-bottom: var(--space-12);
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
}

.chapter-number {
  font-size: var(--fs-sm);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--accent-blue);
  margin-bottom: var(--space-3);
}

.chapter-title {
  font-size: var(--fs-4xl);
  font-weight: 800;
  margin-bottom: var(--space-4);
}

.chapter-description {
  font-size: var(--fs-lg);
  color: var(--text-secondary);
  max-width: 65ch;
}

/* --- Content Layout --- */
.content-wrapper {
  max-width: var(--max-width);
  margin: 0 auto;
}

.content-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-10);
}

.content-block {
  margin-bottom: var(--space-10);
}

.content-block h3 {
  margin-bottom: var(--space-4);
  font-size: var(--fs-2xl);
}

.content-block p {
  margin-bottom: var(--space-4);
}

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

.content-block ul li {
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  color: var(--text-secondary);
  line-height: 1.6;
}

.content-block ul li::before {
  content: '▸';
  color: var(--accent-blue);
  font-weight: 700;
  flex-shrink: 0;
  margin-top: 2px;
}

/* --- Slides Grid --- */
.slides-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-8);
}

.slides-grid.two-col {
  grid-template-columns: repeat(2, 1fr);
}

/* --- Comparison Layout --- */
.comparison-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-6);
}

.comparison-card {
  background: var(--bg-glass);
  border: 1px solid var(--bg-glass-border);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
}

.comparison-card h4 {
  margin-bottom: var(--space-4);
}

/* --- Timeline --- */
.timeline {
  position: relative;
  padding-left: var(--space-10);
}

.timeline::before {
  content: '';
  position: absolute;
  left: 15px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: linear-gradient(to bottom, var(--accent-blue), var(--accent-violet), var(--accent-cyan));
}

.timeline-item {
  position: relative;
  margin-bottom: var(--space-8);
  padding-left: var(--space-6);
}

.timeline-item::before {
  content: '';
  position: absolute;
  left: calc(-1 * var(--space-10) + 10px);
  top: 6px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--accent-blue);
  border: 2px solid var(--bg-primary);
  box-shadow: var(--shadow-glow-blue);
}

.timeline-item .timeline-year {
  font-size: var(--fs-sm);
  font-weight: 700;
  color: var(--accent-blue);
  margin-bottom: var(--space-1);
}

.timeline-item h4 {
  font-size: var(--fs-lg);
  margin-bottom: var(--space-2);
}

.timeline-item p {
  font-size: var(--fs-sm);
  color: var(--text-secondary);
}

/* --- Interactive Section Divider --- */
.section-divider {
  text-align: center;
  padding: var(--space-12) 0;
  position: relative;
}

.section-divider::before {
  content: '';
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  top: 0;
  width: 200px;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--accent-blue), transparent);
}

.section-divider h3 {
  font-size: var(--fs-2xl);
  margin-bottom: var(--space-3);
}

.section-divider p {
  color: var(--text-muted);
  margin: 0 auto;
}

/* --- Footer --- */
.site-footer {
  padding: var(--space-16) var(--space-6);
  background: var(--bg-secondary);
  border-top: 1px solid var(--bg-glass-border);
  text-align: center;
}

.site-footer p {
  color: var(--text-muted);
  font-size: var(--fs-sm);
  margin: 0 auto;
}

/* --- Responsive --- */
@media (max-width: 1024px) {
  .main-content {
    margin-left: 0;
  }

  .chapter-section {
    padding: var(--space-16) var(--space-6);
  }

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

  .slides-grid.two-col {
    grid-template-columns: 1fr;
  }

  .hero-stats {
    gap: var(--space-8);
  }
}

@media (max-width: 768px) {
  .hero-section {
    padding: var(--space-10) var(--space-4);
  }

  .hero-stats {
    flex-direction: column;
    gap: var(--space-6);
  }

  .chapter-title {
    font-size: var(--fs-3xl);
  }
}