:root {
    --bg: #07070f;
    --surface: rgba(12,12,26,0.97);
    --surface-2: rgba(255,255,255,0.04);
    --accent: #00ffe7;
    --gold: #ffd166;
    --pink: #ff6b9d;
    --purple: #a78bfa;
    --green: #34d399;
    --text: #dde1f0;
    --text-mid: rgba(221,225,240,0.65);
    --text-muted: rgba(221,225,240,0.45);
    --dim: #5a5a80;
    --border: rgba(0,255,231,0.14);
    --border-soft: rgba(255,255,255,0.08);
  }

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

  html { scroll-behavior: smooth; }

  body {
    font-family: 'Space Mono', monospace;
    background: var(--bg);
    color: var(--text);
    overflow-x: hidden;
  }

  body::before {
    content: '';
    position: fixed; inset: 0; pointer-events: none; z-index: 999;
    background: repeating-linear-gradient(0deg, transparent, transparent 3px, rgba(0,0,0,.03) 3px, rgba(0,0,0,.03) 6px);
  }

  nav {
    position: fixed; top: 0; left: 0; right: 0; z-index: 100;
    display: flex; align-items: center; justify-content: space-between;
    padding: 1.1rem 3rem;
    background: rgba(6,6,16,0.96);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
  }

  .nav-logo {
    display: flex;
    align-items: center;
    gap: 0.7rem;
    text-decoration: none;
  }

  .nav-logo-icon {
    width: 34px;
    height: 34px;
    border-radius: 50%;
    flex-shrink: 0;
    display: block;
    filter: brightness(1.45) saturate(1.1);
    box-shadow: 0 0 10px rgba(0,255,231,.3);
  }

  .nav-logo-text {
    font-family: 'Cormorant Garamond', serif;
    font-size: 1.15rem;
    font-weight: 600;
    color: var(--text);
    letter-spacing: 0.01em;
  }

  .nav-logo-text em {
    font-style: italic;
    font-weight: 600;
    color: var(--gold);
  }

  .nav-links {
    display: flex; gap: 2.4rem; list-style: none;
  }

  .nav-links a {
    font-size: 0.78rem;
    font-weight: 400;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--text-mid);
    text-decoration: none;
    transition: color 0.2s;
  }

  .nav-links a:hover { color: var(--accent); }

  .nav-cta {
    font-size: 0.75rem;
    font-weight: 700;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    font-family: 'Sora', sans-serif;
    color: var(--bg);
    background: var(--accent);
    padding: 0.55rem 1.4rem;
    border-radius: 6px;
    text-decoration: none;
    transition: background 0.2s, box-shadow 0.2s;
  }

  .nav-cta:hover { background: #4dfff0; box-shadow: 0 0 16px rgba(0,255,231,0.35); }

  .nav-right {
    display: flex;
    align-items: center;
    gap: 1.2rem;
  }

  .nav-social {
    display: flex;
    gap: 0.5rem;
    align-items: center;
  }

  .nav-social a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    border-radius: 7px;
    border: 1px solid var(--border);
    color: var(--dim);
    text-decoration: none;
    transition: 0.2s;
    background: rgba(255,255,255,0.02);
  }

  .nav-social a:hover {
    color: var(--accent);
    border-color: var(--accent);
    background: rgba(0,255,231,0.07);
  }

  .nav-social svg {
    width: 16px;
    height: 16px;
  }

  @media (max-width: 860px) {
    .nav-cta { display: none; }
    .nav-social { display: flex; }
  }

  .hero {
    min-height: 100vh;
    background: var(--bg);
    display: flex; align-items: center; justify-content: center;
    position: relative; overflow: hidden;
    padding: 4.5rem 2rem 5rem;
  }

  #heroCanvas {
    position: absolute; inset: 0;
    width: 100%; height: 100%;
    pointer-events: none;
  }

  .hero-glow {
    position: absolute; top: 20%; left: 50%;
    transform: translateX(-50%);
    width: 700px; height: 400px;
    background: radial-gradient(ellipse, rgba(0,255,231,0.09) 0%, transparent 70%);
    pointer-events: none;
  }

  .hero-content {
    position: relative; z-index: 2;
    text-align: center; max-width: 820px;
    animation: fadeUp 1s ease both;
  }

  @keyframes fadeUp {
    from { opacity: 0; transform: translateY(32px); }
    to   { opacity: 1; transform: translateY(0); }
  }

  .hero-eyebrow {
    display: inline-flex; align-items: center; gap: 0.7rem;
    font-size: 0.7rem; letter-spacing: 0.2em; text-transform: uppercase;
    color: var(--accent);
    margin-bottom: 1.8rem;
  }

  .hero-eyebrow::before,
  .hero-eyebrow::after {
    content: '';
    display: block; width: 36px; height: 1px;
    background: var(--accent); opacity: 0.5;
  }

  .hero-title {
    font-family: 'Cormorant Garamond', serif;
    font-size: clamp(2.8rem, 7vw, 5.2rem);
    font-weight: 600;
    line-height: 1.05;
    color: var(--text);
    margin-bottom: 0.3rem;
    letter-spacing: 0.01em;
  }

  .hero-title em {
    font-style: italic;
    font-weight: 600;
    color: var(--gold);
    text-shadow: 0 0 24px rgba(255,209,102,0.35);
  }

  .hero-subtitle-line {
    font-family: 'Sora', sans-serif;
    font-size: clamp(1.1rem, 2.5vw, 1.6rem);
    font-style: italic;
    color: var(--gold);
    margin-bottom: 2rem;
    letter-spacing: 0.02em;
  }

  .hero-desc {
    font-size: 1rem;
    line-height: 1.8;
    color: var(--text-mid);
    max-width: 580px;
    margin: 0 auto 3rem;
    font-weight: 400;
  }

  .hero-btns {
    display: flex; gap: 1rem; justify-content: center; flex-wrap: wrap;
  }

  .btn-primary {
    font-family: 'Sora', sans-serif;
    font-size: 0.8rem; font-weight: 700;
    letter-spacing: 0.1em; text-transform: uppercase;
    color: var(--bg); background: var(--accent);
    padding: 0.85rem 2.4rem; border-radius: 6px;
    text-decoration: none;
    transition: background 0.2s, transform 0.15s, box-shadow 0.2s;
    display: inline-block;
  }

  .btn-primary:hover { background: #4dfff0; transform: translateY(-1px); box-shadow: 0 0 20px rgba(0,255,231,0.3); }

  .btn-secondary {
    font-family: 'Sora', sans-serif;
    font-size: 0.8rem; font-weight: 700;
    letter-spacing: 0.1em; text-transform: uppercase;
    color: var(--text-mid);
    border: 1px solid var(--border-soft);
    padding: 0.85rem 2.4rem; border-radius: 6px;
    text-decoration: none;
    transition: border-color 0.2s, color 0.2s;
    display: inline-block;
  }

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

  .stats-bar {
    background: var(--surface);
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
    padding: 1.8rem 3rem;
    display: flex; justify-content: center; gap: 5rem;
    flex-wrap: nowrap;
  }

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

  .stat-num {
    font-family: 'Sora', sans-serif;
    font-size: 2rem; font-weight: 700;
    color: var(--accent);
    display: block;
    text-shadow: 0 0 14px rgba(0,255,231,0.25);
  }

  .stat-label {
    font-size: 0.7rem; letter-spacing: 0.14em;
    text-transform: uppercase; color: var(--text-muted);
  }

  section { padding: 6rem 2rem; }

  .section-inner { max-width: 1100px; margin: 0 auto; }

  .section-eyebrow {
    display: inline-flex; align-items: center; gap: 0.7rem;
    font-size: 0.7rem; letter-spacing: 0.2em; text-transform: uppercase;
    color: var(--accent); margin-bottom: 1rem;
  }

  .section-eyebrow::before {
    content: ''; display: block;
    width: 28px; height: 1px; background: var(--accent); opacity: 0.6;
  }

  .section-heading {
    font-family: 'Sora', sans-serif;
    font-size: clamp(1.8rem, 4vw, 2.8rem);
    font-weight: 700; line-height: 1.15;
    color: var(--text); margin-bottom: 1.2rem;
  }

  .section-heading em { font-style: normal; color: var(--gold); }

  #how { background: var(--bg); }

  .how-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 2rem; margin-top: 3.5rem;
  }

  .how-card {
    padding: 2.2rem 1.8rem;
    border: 1px solid var(--border-soft);
    border-radius: 10px;
    position: relative;
    transition: border-color 0.2s, transform 0.2s, background 0.2s;
    background: var(--surface-2);
  }

  .how-card:hover {
    border-color: var(--accent);
    transform: translateY(-3px);
    background: rgba(0,255,231,0.04);
  }

  .how-num {
    font-family: 'Sora', sans-serif;
    font-size: 3rem; font-weight: 700;
    color: rgba(0,255,231,0.12);
    line-height: 1;
    position: absolute; top: 1.2rem; right: 1.5rem;
  }

  .how-icon {
    width: 42px; height: 42px;
    border-radius: 50%;
    background: rgba(0,255,231,0.08);
    border: 1px solid var(--border);
    display: flex; align-items: center; justify-content: center;
    margin-bottom: 1.3rem;
  }

  .how-icon svg { width: 20px; height: 20px; stroke: var(--accent); fill: none; stroke-width: 1.5; }

  .how-card h3 {
    font-family: 'Sora', sans-serif;
    font-size: 1rem; font-weight: 700;
    color: var(--text); margin-bottom: 0.7rem;
  }

  .how-card p {
    font-size: 0.88rem; line-height: 1.7;
    color: var(--text-muted); font-weight: 400;
  }

  #chapters { background: var(--surface); }

  .chapters-intro {
    display: flex; align-items: flex-end;
    justify-content: space-between; gap: 2rem;
    margin-bottom: 3rem; flex-wrap: wrap;
  }

  .chapters-search {
    display: flex; align-items: center; gap: 0.6rem;
    border: 1px solid var(--border-soft);
    border-radius: 8px; padding: 0.55rem 1rem;
    background: rgba(255,255,255,0.03); min-width: 220px;
  }

  .chapters-search svg { width: 16px; height: 16px; stroke: var(--text-muted); flex-shrink: 0; }

  .chapters-search input {
    border: none; outline: none; background: transparent;
    font-family: 'Space Mono', monospace;
    font-size: 0.85rem; color: var(--text);
    width: 100%;
  }

  .chapters-search input::placeholder { color: var(--dim); }

  .chapters-list {
    border: 1px solid var(--border-soft);
    border-radius: 10px;
    overflow: hidden;
  }

  .chapter-row {
    border-bottom: 1px solid var(--border-soft);
  }

  .chapter-row:last-child { border-bottom: none; }

  .chapter-card {
    background: transparent;
    padding: 1.25rem 1.8rem;
    cursor: pointer;
    display: flex; align-items: center; gap: 1.2rem;
    transition: background 0.18s;
    position: relative;
    width: 100%;
  }

  .chapter-card:hover { background: rgba(255,255,255,0.03); }

  .chapter-card.active { background: rgba(0,255,231,0.06); }

  .chapter-num {
    font-family: 'Sora', sans-serif;
    font-size: 1.2rem; font-weight: 700;
    color: rgba(0,255,231,0.3);
    min-width: 2.4rem; text-align: right;
    transition: color 0.18s; flex-shrink: 0;
  }

  .chapter-card.active .chapter-num { color: var(--accent); }

  .chapter-info { flex: 1; }

  .chapter-name {
    font-family: 'Sora', sans-serif;
    font-size: 0.92rem; font-weight: 700;
    color: var(--text); transition: color 0.18s;
    line-height: 1.3;
  }

  .chapter-card.active .chapter-name { color: var(--accent); }

  .chapter-count {
    font-size: 0.72rem; color: var(--text-muted);
    margin-top: 0.15rem; transition: color 0.18s;
  }

  .chapter-card.active .chapter-count { color: rgba(0,255,231,0.6); }

  .chapter-arrow {
    width: 20px; height: 20px; flex-shrink: 0;
    display: flex; align-items: center; justify-content: center;
    opacity: 0.3; transition: opacity 0.2s, transform 0.25s;
  }

  .chapter-arrow svg { width: 16px; height: 16px; stroke: var(--accent); }

  .chapter-card:hover .chapter-arrow { opacity: 0.8; }
  .chapter-card.active .chapter-arrow { opacity: 1; transform: rotate(90deg); }

  .anim-panel {
    display: none;
    overflow: hidden;
    border-top: 2px solid var(--accent);
    background: rgba(0,0,0,0.25);
    animation: panelIn 0.28s ease;
  }

  @keyframes panelIn {
    from { opacity: 0; transform: translateY(-6px); }
    to   { opacity: 1; transform: translateY(0); }
  }

  .anim-panel.open { display: block; }

  .panel-header {
    display: flex; align-items: center; justify-content: space-between;
    padding: 1.2rem 1.8rem;
    border-bottom: 1px solid var(--border-soft);
    background: rgba(0,255,231,0.03);
  }

  .panel-title {
    font-family: 'Sora', sans-serif;
    font-size: 1.05rem; font-weight: 700; color: var(--text);
  }

  .panel-close {
    width: 28px; height: 28px; border-radius: 50%;
    display: flex; align-items: center; justify-content: center;
    background: transparent; border: 1px solid var(--border-soft);
    cursor: pointer; transition: background 0.15s, border-color 0.15s;
  }

  .panel-close:hover { background: rgba(255,255,255,0.06); border-color: var(--accent); }

  .panel-close svg { width: 14px; height: 14px; stroke: var(--text-muted); }

  .anim-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 1.2rem; padding: 1.5rem 1.8rem;
  }

  .anim-tile {
    border: 1px solid var(--border-soft);
    border-radius: 8px; overflow: hidden;
    transition: border-color 0.2s, transform 0.2s;
    cursor: pointer; text-decoration: none;
    display: block;
  }

  .anim-tile:hover {
    border-color: var(--accent);
    transform: translateY(-2px);
  }

  .anim-preview {
    height: 110px;
    background: var(--bg);
    display: flex; align-items: center; justify-content: center;
    position: relative; overflow: hidden;
  }

  .anim-preview .preview-graph {
    position: absolute; inset: 0;
    display: flex; align-items: flex-end; gap: 4px; padding: 12px;
    opacity: 0.3;
  }

  .anim-preview .preview-graph span {
    flex: 1; background: var(--accent);
    border-radius: 1px 1px 0 0;
    animation: barGrow 2s ease-in-out infinite alternate;
  }

  @keyframes barGrow {
    from { transform: scaleY(0.3); }
    to   { transform: scaleY(1); }
  }

  .anim-preview .preview-graph span:nth-child(2) { animation-delay: 0.15s; }
  .anim-preview .preview-graph span:nth-child(3) { animation-delay: 0.3s; }
  .anim-preview .preview-graph span:nth-child(4) { animation-delay: 0.45s; }
  .anim-preview .preview-graph span:nth-child(5) { animation-delay: 0.6s; }

  .anim-preview .play-btn {
    position: relative; z-index: 2;
    width: 38px; height: 38px; border-radius: 50%;
    background: rgba(0,255,231,0.85);
    display: flex; align-items: center; justify-content: center;
    transition: background 0.2s, transform 0.15s, box-shadow 0.2s;
  }

  .anim-tile:hover .play-btn {
    background: var(--accent);
    transform: scale(1.08);
    box-shadow: 0 0 18px rgba(0,255,231,0.4);
  }

  .anim-preview .play-btn svg {
    width: 16px; height: 16px; fill: var(--bg);
  }

  .anim-info { padding: 0.8rem 1rem; }

  .anim-name {
    font-size: 0.82rem; font-weight: 500;
    color: var(--text); line-height: 1.35;
  }

  .anim-tag {
    display: inline-block; margin-top: 0.35rem;
    font-size: 0.65rem; letter-spacing: 0.08em; text-transform: uppercase;
    color: var(--purple); background: rgba(167,139,250,0.12);
    padding: 0.2rem 0.5rem; border-radius: 4px;
  }

  #features { background: var(--bg); }

  #features .section-heading { color: var(--text); }
  #features .section-heading em { color: var(--gold); }
  #features .section-eyebrow { color: var(--gold); }
  #features .section-eyebrow::before { background: var(--gold); }

  .features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 1.8rem; margin-top: 3.5rem;
  }

  .feature-card {
    padding: 2rem 1.8rem;
    border: 1px solid var(--border-soft);
    border-radius: 10px;
    background: var(--surface-2);
    transition: border-color 0.2s, background 0.2s;
  }

  .feature-card:hover {
    border-color: rgba(255,209,102,0.35);
    background: rgba(255,209,102,0.04);
  }

  .feature-icon {
    width: 44px; height: 44px; margin-bottom: 1.3rem;
    border: 1px solid rgba(255,209,102,0.35);
    border-radius: 50%;
    display: flex; align-items: center; justify-content: center;
  }

  .feature-icon svg {
    width: 20px; height: 20px;
    stroke: var(--gold); fill: none; stroke-width: 1.5;
  }

  .feature-card h3 {
    font-family: 'Sora', sans-serif;
    font-size: 0.95rem; font-weight: 700; color: var(--text);
    margin-bottom: 0.7rem;
  }

  .feature-card p {
    font-size: 0.85rem; line-height: 1.7;
    color: var(--text-muted); font-weight: 400;
  }

  #audience { background: var(--surface); }

  .audience-grid {
    display: grid; grid-template-columns: 1fr 1fr;
    gap: 2rem; margin-top: 3rem;
  }

  @media (max-width: 640px) { .audience-grid { grid-template-columns: 1fr; } }

  .audience-card {
    padding: 2.5rem;
    border-radius: 10px; position: relative; overflow: hidden;
  }

  .audience-card.students {
    background: rgba(0,255,231,0.04);
    border: 1px solid var(--border);
  }

  .audience-card.teachers {
    background: rgba(255,209,102,0.03);
    border: 1px solid rgba(255,209,102,0.18);
  }

  .audience-badge {
    display: inline-block;
    font-family: 'Sora', sans-serif;
    font-size: 0.68rem; letter-spacing: 0.15em; text-transform: uppercase;
    padding: 0.3rem 0.75rem; border-radius: 6px; margin-bottom: 1.2rem;
    font-weight: 700;
  }

  .students .audience-badge {
    background: rgba(0,255,231,0.15); color: var(--accent);
  }

  .teachers .audience-badge {
    background: rgba(255,209,102,0.15); color: var(--gold);
  }

  .audience-card h3 {
    font-family: 'Sora', sans-serif;
    font-size: 1.5rem; font-weight: 700; margin-bottom: 1rem;
  }

  .students h3 { color: var(--text); }
  .teachers h3 { color: var(--text); }

  .audience-list { list-style: none; }

  .audience-list li {
    font-size: 0.88rem; line-height: 1.6;
    padding: 0.55rem 0;
    border-bottom: 1px solid var(--border-soft);
    display: flex; gap: 0.7rem; align-items: flex-start;
    font-weight: 400;
    color: var(--text-mid);
  }

  .audience-list li::before {
    content: '›'; color: var(--accent); flex-shrink: 0;
    font-weight: 700;
  }

  .teachers .audience-list li::before { color: var(--gold); }

  .cta-band {
    background: var(--surface);
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
    padding: 5rem 2rem; text-align: center;
  }

  .cta-band h2 {
    font-family: 'Sora', sans-serif;
    font-size: clamp(1.8rem, 4vw, 2.6rem);
    font-weight: 700; color: var(--text);
    margin-bottom: 1rem;
  }

  .cta-band p {
    font-size: 0.95rem; color: var(--text-muted);
    max-width: 480px; margin: 0 auto 2.4rem; font-weight: 400; line-height: 1.7;
  }

  footer {
    background: var(--bg);
    padding: 3rem;
    display: flex; align-items: center; justify-content: space-between;
    flex-wrap: wrap; gap: 1.5rem;
    border-top: 1px solid var(--border-soft);
  }

  .footer-logo {
    font-family: 'Sora', sans-serif;
    font-size: 1.1rem; font-weight: 600;
    color: var(--gold);
  }

  .footer-logo span { color: var(--text-muted); }

  footer p {
    font-size: 0.75rem; color: var(--dim);
    letter-spacing: 0.05em;
  }

  .footer-copyright {
    font-family: 'Space Mono', monospace;
    color: var(--text-muted);
    letter-spacing: 0.03em;
  }

  @media (max-width: 900px) {
    nav { padding: 1rem 1.5rem; }
    .nav-links { display: none; }
    .stats-bar { gap: 2.5rem; padding: 1.5rem; }
    section { padding: 4.5rem 1.2rem; }
    footer { padding: 2rem 1.5rem; }
  }

  @media (max-width: 560px) {
    .stats-bar {
      gap: 1.4rem;
      padding: 1.1rem 1rem;
      justify-content: space-between;
    }
    .stat-item { flex: 1; min-width: 0; }
    .stat-num { font-size: 1.3rem; }
    .stat-label { font-size: 0.6rem; letter-spacing: 0.06em; white-space: nowrap; }
  }

  .chapter-card[data-hidden="true"] { display: none; }