/* MiniLLM — Airy, Cloud-like Theme */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&display=swap');

:root {
  --bg-start: #f0e6ff;
  --bg-mid: #e0eaff;
  --bg-end: #f5f9ff;
  --text: #1a1a2e;
  --text-dim: #6b7280;
  --accent: #8b5cf6;
  --accent-light: #c4b5fd;
  --accent-glow: rgba(139, 92, 246, 0.3);
  --blue: #3b82f6;
  --orange: #f97316;
  --green: #10b981;
  --card-bg: rgba(255, 255, 255, 0.6);
  --card-border: rgba(255, 255, 255, 0.8);
  --glass: rgba(255, 255, 255, 0.4);
  --glass-border: rgba(255, 255, 255, 0.6);
  --radius: 16px;
  --radius-sm: 10px;
  --font: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
[hidden] { display: none !important; }
/* Ensure all range inputs have adequate touch targets */
input[type="range"] { min-height: 44px; cursor: pointer; }
html { scroll-behavior: smooth; font-size: 16px; }

body {
  font-family: var(--font);
  color: var(--text);
  background: linear-gradient(180deg, var(--bg-start) 0%, var(--bg-mid) 40%, var(--bg-end) 100%);
  background-attachment: fixed;
  min-height: 100vh;
  line-height: 1.7;
  overflow-x: hidden;
}

/* Particles canvas */
.particles-canvas {
  position: fixed;
  top: 0; left: 0;
  width: 100vw; height: 100vh;
  pointer-events: none;
  z-index: 0;
}

/* ===== Chapter Rail (floating nav) ===== */
.chapter-rail {
  position: fixed;
  right: 24px;
  top: 50%;
  transform: translateY(-50%);
  display: flex;
  flex-direction: column;
  gap: 12px;
  z-index: 100;
  opacity: 0;
  transition: opacity 0.5s ease;
}
.chapter-rail.visible { opacity: 1; }
.rail-dot {
  width: 10px; height: 10px;
  border-radius: 50%;
  background: rgba(139, 92, 246, 0.2);
  border: 1.5px solid rgba(139, 92, 246, 0.4);
  text-decoration: none;
  font-size: 0;
  transition: all 0.3s ease;
  position: relative;
}
/* Enlarge touch target without changing visual size */
.rail-dot::after {
  content: '';
  position: absolute;
  top: -17px; left: -17px; right: -17px; bottom: -17px;
}
.rail-dot:hover, .rail-dot.active {
  background: var(--accent);
  transform: scale(1.4);
  box-shadow: 0 0 12px var(--accent-glow);
}
.rail-dot::before {
  content: attr(data-tooltip);
  position: absolute;
  right: 20px;
  top: 50%;
  transform: translateY(-50%);
  background: rgba(255,255,255,0.9);
  backdrop-filter: blur(8px);
  padding: 4px 10px;
  border-radius: 6px;
  font-size: 12px;
  color: var(--text);
  white-space: nowrap;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s;
}
.rail-dot:hover::before { opacity: 1; }

/* ===== Story Sections ===== */
.story-section {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 4rem 2rem;
  z-index: 1;
}
.story-content {
  max-width: 900px;
  width: 100%;
  text-align: center;
}
.story-split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: center;
  text-align: left;
}

/* ===== Hero ===== */
.hero-section { min-height: 100vh; }
.hero-title {
  font-size: clamp(2.5rem, 6vw, 4rem);
  font-weight: 800;
  margin-top: 1rem;
  background: linear-gradient(135deg, var(--accent), var(--blue));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-sub {
  font-size: 1.2rem;
  color: var(--text-dim);
  margin-top: 0.5rem;
  font-weight: 300;
}
#hero-neuron {
  display: block;
  margin: 0 auto;
  max-width: 300px;
}

.scroll-hint {
  margin-top: 3rem;
  color: var(--text-dim);
  font-size: 0.85rem;
  letter-spacing: 0.05em;
}
.scroll-arrow {
  font-size: 1.5rem;
  animation: bounce 2s infinite;
}
@keyframes bounce {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(8px); }
}

/* ===== Reveal Animations ===== */
.fade-in { opacity: 0; animation: fadeUp 1s ease forwards; }
.delay-1 { animation-delay: 0.3s; }
.delay-2 { animation-delay: 0.6s; }
.delay-3 { animation-delay: 0.9s; }

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(30px); }
  to { opacity: 1; transform: translateY(0); }
}

.reveal {
  opacity: 0;
  transform: translateY(40px);
  transition: opacity 0.8s ease, transform 0.8s ease;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ===== Typography ===== */
h2 {
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 800;
  color: var(--text);
  margin-bottom: 0.5rem;
}
.story-text p {
  font-size: 1.05rem;
  color: var(--text-dim);
  margin-bottom: 1rem;
  line-height: 1.8;
}
.story-text em {
  color: var(--accent);
  font-style: normal;
  font-weight: 600;
}

/* ===== Interactive Widgets ===== */
.interactive-widget {
  background: var(--card-bg);
  backdrop-filter: blur(12px);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-top: 1rem;
}
.interactive-widget label {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  margin-bottom: 0.8rem;
  font-size: 0.9rem;
  font-weight: 500;
}
.interactive-widget input[type="range"] {
  flex: 1;
  accent-color: var(--accent);
  height: 6px;
  min-height: 44px;
  cursor: pointer;
}
.interactive-widget span {
  min-width: 40px;
  text-align: right;
  font-weight: 600;
  color: var(--accent);
  font-variant-numeric: tabular-nums;
}

/* ===== Canvas ===== */
.story-viz canvas {
  display: block;
  width: 100%;
  max-width: 500px;
  border-radius: var(--radius);
  background: rgba(255,255,255,0.3);
  backdrop-filter: blur(4px);
}

/* ===== Activation Display ===== */
.activation-display {
  margin: 2rem auto;
  max-width: 700px;
}
.computation-flow {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  flex-wrap: wrap;
}
.comp-box {
  background: var(--card-bg);
  backdrop-filter: blur(12px);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-sm);
  padding: 1rem 1.5rem;
  text-align: center;
  min-width: 120px;
}
.comp-box.highlight {
  border-color: var(--accent);
  box-shadow: 0 0 20px var(--accent-glow);
}
.comp-label { font-size: 0.75rem; color: var(--text-dim); text-transform: uppercase; letter-spacing: 0.05em; margin-bottom: 0.3rem; }
.comp-value { font-size: 1.5rem; font-weight: 700; color: var(--text); font-variant-numeric: tabular-nums; }
.comp-value.big { font-size: 2rem; color: var(--accent); }
.comp-arrow { font-size: 1.5rem; color: var(--text-dim); }

#sigmoid-curve { display: block; margin: 0.5rem auto 0; }

/* ===== Network Reveal ===== */
#network-reveal {
  display: block;
  margin: 0 auto;
  width: 100%;
  max-width: 800px;
  border-radius: var(--radius);
  background: rgba(255,255,255,0.2);
}

/* ===== Chapter Grid ===== */
.chapter-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 1rem;
  margin-top: 1.5rem;
}
.chapter-card {
  display: flex;
  flex-direction: column;
  padding: 1.2rem;
  background: var(--card-bg);
  backdrop-filter: blur(12px);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-sm);
  text-decoration: none;
  color: var(--text);
  transition: all 0.3s ease;
}
.chapter-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 30px rgba(139, 92, 246, 0.15);
  border-color: var(--accent-light);
}
.ch-num { font-size: 0.75rem; color: var(--accent); font-weight: 700; letter-spacing: 0.1em; }
.ch-title { font-size: 0.95rem; font-weight: 700; margin: 0.3rem 0; }
.ch-desc { font-size: 0.8rem; color: var(--text-dim); }

/* ===== Train Section ===== */
.train-section {
  min-height: auto;
  padding: 6rem 2rem 4rem;
}
.trainer-container {
  max-width: 700px;
  margin: 0 auto;
  text-align: left;
}
.train-step {
  background: var(--card-bg);
  backdrop-filter: blur(12px);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-bottom: 1rem;
}
.train-step h3 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 1rem;
  color: var(--text);
}

/* Preset buttons */
.preset-grid {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  margin-bottom: 1rem;
}
.preset-btn {
  padding: 0.6rem 1.2rem;
  border: 1.5px solid var(--card-border);
  border-radius: 24px;
  background: rgba(255,255,255,0.5);
  cursor: pointer;
  font-family: var(--font);
  font-size: 0.85rem;
  font-weight: 500;
  transition: all 0.2s;
  color: var(--text);
}
.preset-btn:hover { border-color: var(--accent-light); }
.preset-btn.active {
  background: var(--accent);
  color: white;
  border-color: var(--accent);
}
.custom-text-area {
  width: 100%;
  height: 120px;
  border: 1.5px solid var(--card-border);
  border-radius: var(--radius-sm);
  padding: 0.8rem;
  font-family: var(--font);
  font-size: 0.85rem;
  resize: vertical;
  background: rgba(255,255,255,0.5);
  margin-bottom: 1rem;
}
.data-preview {
  background: rgba(255,255,255,0.4);
  border-radius: var(--radius-sm);
  padding: 0.8rem;
  max-height: 100px;
  overflow-y: auto;
}
.preview-label { font-size: 0.7rem; text-transform: uppercase; letter-spacing: 0.05em; color: var(--text-dim); margin-bottom: 0.3rem; }
.preview-text { font-size: 0.8rem; color: var(--text-dim); line-height: 1.5; white-space: pre-wrap; }

/* Config */
.config-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}
.config-item { display: flex; flex-direction: column; gap: 0.3rem; }
.config-item label { font-size: 0.8rem; font-weight: 600; color: var(--text-dim); }
.config-item select, .config-item input[type="range"] { accent-color: var(--accent); }
.config-item select {
  padding: 0.5rem;
  border: 1.5px solid var(--card-border);
  border-radius: 8px;
  background: rgba(255,255,255,0.5);
  font-family: var(--font);
  font-size: 0.85rem;
}
#temp-val { font-weight: 600; color: var(--accent); font-size: 0.85rem; }

/* Train button */
.train-btn {
  display: block;
  width: 100%;
  padding: 1rem;
  background: linear-gradient(135deg, var(--accent), var(--blue));
  color: white;
  border: none;
  border-radius: var(--radius-sm);
  font-family: var(--font);
  font-size: 1.1rem;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.3s;
  letter-spacing: 0.02em;
}
.train-btn:hover { transform: translateY(-2px); box-shadow: 0 8px 25px var(--accent-glow); }
.train-btn:disabled { opacity: 0.5; cursor: not-allowed; transform: none; }

/* Dashboard */
.training-dashboard { margin-top: 1rem; }
.dash-row { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; margin-bottom: 1rem; }
.dash-card {
  background: rgba(255,255,255,0.4);
  border-radius: var(--radius-sm);
  padding: 1rem;
  text-align: center;
}
.dash-label { font-size: 0.7rem; text-transform: uppercase; letter-spacing: 0.05em; color: var(--text-dim); }
.dash-value { font-size: 1.5rem; font-weight: 700; color: var(--text); font-variant-numeric: tabular-nums; }
#loss-chart { display: block; margin: 0.5rem auto 0; width: 100%; }

.progress-bar {
  height: 8px;
  background: rgba(139, 92, 246, 0.1);
  border-radius: 4px;
  margin-top: 0.5rem;
  overflow: hidden;
}
.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent), var(--blue));
  border-radius: 4px;
  width: 0%;
  transition: width 0.3s;
}

.sample-output {
  background: rgba(255,255,255,0.4);
  border-radius: var(--radius-sm);
  padding: 1rem;
}
.sample-label { font-size: 0.7rem; text-transform: uppercase; letter-spacing: 0.05em; color: var(--text-dim); margin-bottom: 0.5rem; }
.sample-text { font-family: 'Inter', monospace; font-size: 0.85rem; color: var(--text); line-height: 1.6; min-height: 60px; white-space: pre-wrap; word-wrap: break-word; overflow-wrap: break-word; max-width: 100%; overflow-x: hidden; }

/* Generate area */
.generate-area { margin: 1rem 0; }
.gen-input {
  width: 100%;
  padding: 0.8rem 1rem;
  border: 2px solid var(--accent-light);
  border-radius: var(--radius-sm);
  font-family: var(--font);
  font-size: 1rem;
  background: rgba(255,255,255,0.6);
  outline: none;
  transition: border-color 0.2s;
}
.gen-input:focus { border-color: var(--accent); }
.gen-output {
  margin-top: 1rem;
  padding: 1rem;
  background: rgba(255,255,255,0.4);
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  line-height: 1.7;
  min-height: 80px;
  white-space: pre-wrap;
  word-wrap: break-word;
  overflow-wrap: break-word;
  max-width: 100%;
  overflow-x: hidden;
}

.share-row { display: flex; gap: 0.5rem; margin-top: 1rem; }
.share-btn, .download-btn {
  padding: 0.6rem 1.2rem;
  border: 1.5px solid var(--card-border);
  border-radius: 8px;
  background: rgba(255,255,255,0.5);
  cursor: pointer;
  font-family: var(--font);
  font-size: 0.85rem;
  font-weight: 500;
  transition: all 0.2s;
}
.share-btn:hover, .download-btn:hover { border-color: var(--accent); }

.share-link {
  margin-top: 0.5rem;
  padding: 0.5rem;
  background: rgba(139, 92, 246, 0.05);
  border-radius: 6px;
  font-size: 0.85rem;
}
.share-link a { color: var(--accent); }

/* ===== N-gram Trainer UI ===== */
.train-stats {
  margin-top: 0.8rem; padding: 0.8rem; background: rgba(16,185,129,0.1);
  border-radius: var(--radius-sm); font-size: 0.85rem; color: var(--green); text-align: center;
}
.gen-prompt-echo { color: var(--text); }
.gen-continuation { color: var(--accent); font-weight: 500; }
.gen-controls { margin-top: 0.8rem; }
.gen-again-btn {
  padding: 0.5rem 1rem; border: 1.5px solid var(--accent); border-radius: 8px;
  background: rgba(139,92,246,0.1); cursor: pointer; font-family: var(--font);
  font-size: 0.85rem; font-weight: 600; color: var(--accent);
}
.gen-again-btn:hover { background: var(--accent); color: white; }
.add-cat-select {
  padding: 0.5rem; border: 1.5px solid var(--card-border); border-radius: 8px;
  background: rgba(255,255,255,0.5); font-family: var(--font); font-size: 0.85rem;
}

/* Markov */
.markov-controls { display: flex; gap: 0.5rem; align-items: center; }

/* ===== Footer ===== */
.site-footer {
  text-align: center;
  padding: 2rem;
  color: var(--text-dim);
  font-size: 0.85rem;
}
.site-footer a { color: var(--accent); text-decoration: none; }
.site-footer a:hover { text-decoration: underline; }

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .story-split { grid-template-columns: 1fr; gap: 1.5rem; }
  .chapter-grid { grid-template-columns: 1fr 1fr; }
  .config-grid { grid-template-columns: 1fr; }
  .dash-row { grid-template-columns: 1fr; }
  .chapter-rail { display: none; }
  .computation-flow { flex-direction: column; }
  .comp-arrow { transform: rotate(90deg); }
  .preset-btn { min-height: 44px; padding: 0.7rem 1.2rem; }
  .btn, .btn-sm { min-height: 44px; }
  .gen-again-btn { min-height: 44px; padding: 0.6rem 1.2rem; }
  .share-btn, .download-btn { min-height: 44px; }
  .train-btn { min-height: 48px; }
  .chapter-nav a { min-height: 44px; display: inline-flex; align-items: center; }
}
@media (max-width: 480px) {
  .chapter-grid { grid-template-columns: 1fr; }
  .preset-grid { flex-direction: column; }
}

/* Responsive inline grids */
.responsive-grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}
@media (max-width: 768px) {
  .responsive-grid-2 { grid-template-columns: 1fr !important; }
}

/* ===== Chapter Page Styles ===== */

.chapter-content {
  max-width: 820px;
  margin: 5rem auto 3rem;
  padding: 0 2rem;
  position: relative;
  z-index: 1;
}

.chapter-header {
  text-align: center;
  padding: 2rem 0 3rem;
}

.chapter-number {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  background: rgba(139, 92, 246, 0.1);
  padding: 0.3rem 1rem;
  border-radius: 20px;
  margin-bottom: 0.8rem;
}

.chapter-content h1 {
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 800;
  background: linear-gradient(135deg, var(--accent), var(--blue));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin: 0.5rem 0;
}

.chapter-content h2 {
  font-size: 1.5rem;
  font-weight: 700;
  margin: 0 0 0.8rem;
}

.chapter-content h3 {
  font-size: 1.15rem;
  font-weight: 600;
  margin: 0 0 0.5rem;
  color: var(--text);
}

.chapter-content p {
  font-size: 1.02rem;
  color: #2d3748;
  line-height: 1.8;
  margin-bottom: 1rem;
}

.chapter-content ul, .chapter-content ol {
  padding-left: 2rem;
  margin-bottom: 1rem;
  color: #2d3748;
}

.chapter-content li {
  line-height: 1.7;
  margin-bottom: 0.4rem;
  font-size: 1rem;
}

.chapter-content strong {
  color: #1a202c;
}

.chapter-content .section {
  margin-bottom: 3rem;
  padding-bottom: 1rem;
}

/* Fade in up animation for chapter elements */
.fade-in-up {
  opacity: 0;
  animation: fadeUp 0.8s ease forwards;
}

/* Interactive area */
.interactive-area {
  background: var(--card-bg);
  backdrop-filter: blur(12px);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-top: 1rem;
}

/* Grid helpers */
.grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
  align-items: start;
}

@media (max-width: 768px) {
  .grid-2 { grid-template-columns: 1fr; }
}

/* Slider groups */
.slider-group {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  margin-bottom: 0.8rem;
}

.slider-group label {
  font-size: 0.9rem;
  font-weight: 600;
  min-width: 60px;
  color: var(--text);
}

.slider-group input[type="range"] {
  flex: 1;
  accent-color: var(--accent);
  height: 6px;
  min-height: 44px;
  cursor: pointer;
}

.slider-value {
  min-width: 45px;
  text-align: right;
  font-weight: 700;
  color: var(--accent);
  font-variant-numeric: tabular-nums;
  font-size: 0.9rem;
}

/* Stats row */
.stats {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

.stat {
  flex: 1;
  min-width: 80px;
  background: rgba(255, 255, 255, 0.4);
  border-radius: var(--radius-sm);
  padding: 0.8rem;
  text-align: center;
}

.chapter-content .stat-value {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--accent);
  font-variant-numeric: tabular-nums;
}

.chapter-content .stat-label {
  font-size: 0.7rem;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-top: 0.2rem;
}

/* Narration callout */
.narration {
  margin-top: 1rem;
  padding: 1rem;
  background: rgba(139, 92, 246, 0.05);
  border-radius: var(--radius-sm);
  border-left: 3px solid var(--accent);
  font-size: 0.9rem;
  color: #374151;
  line-height: 1.7;
}

.narration strong { color: #1a202c; }

/* Buttons */
.btn {
  display: inline-block;
  padding: 0.7rem 1.4rem;
  border: none;
  border-radius: var(--radius-sm);
  font-family: var(--font);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
}

.btn-sm { padding: 0.5rem 1rem; font-size: 0.85rem; }

.btn-primary {
  background: linear-gradient(135deg, var(--accent), var(--blue));
  color: white;
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 15px var(--accent-glow);
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.5);
  border: 1.5px solid var(--card-border);
  color: var(--text);
}

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

/* Tooltips */
.tooltip[data-tip] {
  position: relative;
  border-bottom: 1.5px dashed var(--accent-light);
  cursor: help;
  color: var(--accent);
  font-weight: 500;
}

.tooltip[data-tip]:hover::after {
  content: attr(data-tip);
  position: absolute;
  bottom: 100%;
  left: 50%;
  transform: translateX(-50%);
  background: rgba(30, 41, 59, 0.9);
  color: white;
  padding: 0.5rem 0.8rem;
  border-radius: 8px;
  font-size: 0.8rem;
  font-weight: 400;
  white-space: nowrap;
  max-width: 280px;
  white-space: normal;
  z-index: 50;
  pointer-events: none;
  margin-bottom: 6px;
  line-height: 1.4;
}

/* Canvas in chapters */
.chapter-content canvas {
  display: block;
  width: 100%;
  max-width: 500px;
  border-radius: var(--radius);
  background: rgba(255, 255, 255, 0.3);
  backdrop-filter: blur(4px);
}

/* Card blocks */
.card {
  background: var(--card-bg);
  backdrop-filter: blur(12px);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-bottom: 1rem;
}

/* Controls group */
.controls, .control-group {
  display: flex;
  gap: 0.8rem;
  align-items: center;
  flex-wrap: wrap;
  margin: 0.8rem 0;
}

.control-group label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-dim);
}

.control-group select, .controls select {
  padding: 0.4rem 0.8rem;
  border: 1.5px solid var(--card-border);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.5);
  font-family: var(--font);
  font-size: 0.85rem;
}

/* Layer slider */
.layer-slider {
  margin: 0.5rem 0;
}

/* Playground layout */
.playground-layout {
  display: grid;
  grid-template-columns: 1fr 280px;
  gap: 1.5rem;
  align-items: start;
}

.playground-main canvas {
  max-width: 100%;
}

.playground-sidebar {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

@media (max-width: 768px) {
  .playground-layout { grid-template-columns: 1fr; }
}

/* Code blocks */
.chapter-content code {
  background: rgba(139, 92, 246, 0.08);
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
  font-size: 0.88rem;
  font-family: 'Fira Code', 'JetBrains Mono', monospace;
}

.chapter-content pre {
  background: rgba(30, 41, 59, 0.05);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-sm);
  padding: 1rem;
  overflow-x: auto;
  font-size: 0.85rem;
  line-height: 1.6;
}

/* ===== Chapter Nav Bar ===== */
.chapter-nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.8rem 1.5rem;
  background: rgba(255,255,255,0.7);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--card-border);
  z-index: 100;
}
.chapter-nav a { color: var(--accent); text-decoration: none; font-weight: 600; font-size: 0.9rem; }
.chapter-nav .nav-title { font-weight: 700; color: var(--text); }
.chapter-body {
  max-width: 900px;
  margin: 5rem auto 3rem;
  padding: 0 2rem;
}

/* Train stats */
.train-stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.8rem;
  margin: 1rem 0;
}
.stat-item {
  background: rgba(255,255,255,0.4);
  border-radius: var(--radius-sm);
  padding: 0.8rem;
  text-align: center;
}
.stat-value { font-size: 1.3rem; font-weight: 700; color: var(--accent); }
.stat-label { font-size: 0.7rem; color: var(--text-dim); text-transform: uppercase; letter-spacing: 0.05em; margin-top: 0.2rem; }
.train-explanation {
  margin-top: 1rem;
  padding: 1rem;
  background: rgba(139, 92, 246, 0.05);
  border-radius: var(--radius-sm);
  border-left: 3px solid var(--accent);
}
.train-explanation p { font-size: 0.9rem; color: var(--text-dim); line-height: 1.7; margin: 0; }
.train-explanation strong { color: var(--text); }
.train-explanation em { color: var(--accent); font-style: normal; }

/* Generated text styling */
.seed-text { color: var(--text-dim); }
.gen-text { color: var(--accent); font-weight: 500; }

.gen-controls { margin-top: 0.5rem; }
.gen-again-btn {
  padding: 0.5rem 1rem;
  border: 1.5px solid var(--card-border);
  border-radius: 8px;
  background: rgba(255,255,255,0.5);
  cursor: pointer;
  font-family: var(--font);
  font-size: 0.85rem;
}

.markov-controls { display: flex; gap: 0.5rem; align-items: center; }

#sample-text {
  margin-top: 1rem;
  padding: 1rem;
  background: rgba(255,255,255,0.4);
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  line-height: 1.7;
  white-space: pre-wrap;
}

@media (max-width: 768px) {
  .train-stats { grid-template-columns: repeat(2, 1fr); }
}

/* Loading cursor for generation */
.gen-loading {
  animation: blink 0.5s infinite;
}
@keyframes blink {
  0%, 50% { opacity: 1; }
  51%, 100% { opacity: 0; }
}

/* Collapsible sections */
.collapsible-header {
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.8rem 1rem;
  background: rgba(139, 92, 246, 0.06);
  border: 1px solid rgba(139, 92, 246, 0.15);
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--text);
  user-select: none;
  transition: background 0.2s;
}
.collapsible-header:hover { background: rgba(139, 92, 246, 0.12); }
.collapsible-header::before {
  content: '▸';
  font-size: 0.8rem;
  transition: transform 0.2s;
  color: var(--accent);
}
.collapsible-header.open::before { transform: rotate(90deg); }
.collapsible-body {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, padding 0.3s ease;
  padding: 0 1rem;
  overflow-x: hidden;
}
.collapsible-body.open {
  max-height: 2000px;
  padding: 1rem;
}

/* Make all chapter canvases fill their container */
.chapter-content canvas,
.interactive-area canvas {
  width: 100%;
  max-width: 100%;
  height: auto;
}