:root {
  --bg: #000000;
  --panel: #0a0a0a;
  --panel-2: #111111;
  --text: #ffffff;
  --muted: #bfbfbf;
  --brand: #ffffff;
  --brand-2: #d9d9d9;
  --accent: #e5e5e5;
  --success: #e0e0e0;
  --error: #cccccc;
  --shadow: 0 10px 30px rgba(0,0,0,.6), 0 2px 10px rgba(0,0,0,.5);
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: Inter, system-ui, -apple-system, Segoe UI, Roboto, Arial, "Noto Sans", "Apple Color Emoji", "Segoe UI Emoji";
  color: var(--text);
  background:
    radial-gradient(1200px 600px at -10% -20%, rgba(255,255,255,.10), transparent 50%),
    radial-gradient(900px 500px at 120% -10%, rgba(255,255,255,.06), transparent 50%),
    radial-gradient(1000px 500px at 10% 120%, rgba(255,255,255,.04), transparent 50%),
    var(--bg);
}

.container { width: min(1100px, 92%); margin: 0 auto; }

.site-header {
  position: sticky; top: 0; z-index: 50;
  backdrop-filter: saturate(140%) blur(10px);
  background: linear-gradient(180deg, rgba(11,16,32,.8), rgba(11,16,32,.35) 70%, transparent);
  border-bottom: 1px solid rgba(255,255,255,.06);
}
.header-inner { display: flex; align-items: center; justify-content: space-between; padding: 14px 0; }
.brand { display: flex; align-items: center; gap: 10px; }
.logo { width: 36px; height: 36px; display: grid; place-items: center; border-radius: 10px; background: linear-gradient(135deg, var(--brand), var(--brand-2)); color: #000000; font-weight: 800; }
.brand-text { line-height: 1; }
.brand-text strong { display: block; letter-spacing: .3px; }
.brand-text span { color: var(--muted); font-size: 12px; }
.nav { display: flex; gap: 18px; }
.nav a { color: var(--muted); text-decoration: none; font-weight: 600; }
.nav a:hover { color: var(--text); }

.hero { padding: 64px 0 40px; }
.hero-inner { display: grid; grid-template-columns: 1.2fr .8fr; gap: 28px; align-items: center; }
.hero-copy h1 { font-size: 44px; margin: 0 0 10px; }
.hero-copy p { color: var(--muted); margin: 0 0 18px; }
.hero-cta { display: flex; gap: 12px; }

.hero-card { background: linear-gradient(180deg, rgba(255,255,255,.06), rgba(255,255,255,.03)); border: 1px solid rgba(255,255,255,.06); border-radius: 16px; box-shadow: var(--shadow); overflow: hidden; }
.hero-card .card-head { padding: 12px 14px; font-weight: 700; background: linear-gradient(135deg, rgba(255,255,255,.16), rgba(255,255,255,.08)); border-bottom: 1px solid rgba(255,255,255,.07); }
.hero-card .card-body { padding: 10px; display: grid; gap: 8px; }
.session { background: rgba(255,255,255,.04); border: 1px solid rgba(255,255,255,.06); border-radius: 12px; padding: 12px; display: flex; align-items: center; justify-content: space-between; }
.session-title { font-weight: 700; }
.session-sub { color: var(--muted); font-size: 12px; }

.catalog { padding: 24px 0 40px; }
.catalog h2, .approach h2, .contact h2 { margin: 0 0 16px; }
.grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.grid.two { grid-template-columns: repeat(2, 1fr); }

.card { background: linear-gradient(180deg, rgba(255,255,255,.06), rgba(255,255,255,.03)); border: 1px solid rgba(255,255,255,.06); border-radius: 16px; padding: 16px; box-shadow: var(--shadow); }
.class-card h3 { margin: 8px 0; }
.class-icon { font-size: 32px; }
.pill-list { list-style: none; padding: 0; margin: 10px 0 18px; display: flex; flex-wrap: wrap; gap: 8px; }
.pill-list li { font-size: 12px; color: var(--bg); background: linear-gradient(135deg, var(--brand), var(--brand-2)); padding: 6px 10px; border-radius: 999px; font-weight: 700; }

.btn { display: inline-flex; align-items: center; justify-content: center; gap: 8px; padding: 10px 14px; border-radius: 12px; text-decoration: none; color: var(--text); font-weight: 800; letter-spacing: .3px; border: 1px solid rgba(255,255,255,.08); background: rgba(255,255,255,.04); }
.btn:hover { transform: translateY(-1px); box-shadow: var(--shadow); }
.btn-primary { background: linear-gradient(135deg, var(--brand), var(--brand-2)); color: #000000; }
.btn-ghost { background: transparent; }
.btn-small { padding: 8px 10px; font-size: 12px; }

.approach, .contact { padding: 8px 0 40px; }

.site-footer { border-top: 1px solid rgba(255,255,255,.06); padding: 16px 0; }
.footer-inner { display: flex; align-items: center; justify-content: space-between; color: var(--muted); }
.footer-links { display: flex; gap: 12px; }
.footer-links a { color: var(--muted); text-decoration: none; }
.footer-links a:hover { color: var(--text); }

/* Class Pages */
.lesson-header { padding: 28px 0 8px; }
.lesson-title { font-size: 32px; margin: 0; }
.lesson-sub { color: var(--muted); margin: 6px 0 0; }
.lesson-layout { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.lesson-panel { background: linear-gradient(180deg, rgba(255,255,255,.06), rgba(255,255,255,.03)); border: 1px solid rgba(255,255,255,.06); border-radius: 16px; padding: 16px; box-shadow: var(--shadow); }
.lesson-panel h3 { margin: 8px 0 12px; }
.metrics { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; }
.metric { background: rgba(255,255,255,.05); border: 1px solid rgba(255,255,255,.06); border-radius: 12px; padding: 10px; text-align: center; }
.metric .label { color: var(--muted); font-size: 12px; }
.metric .value { font-size: 20px; font-weight: 800; }

/* Modal */
.modal-backdrop { position: fixed; inset: 0; background: rgba(2,6,23,.7); display: grid; place-items: center; z-index: 100; }
.modal { width: min(520px, 92%); background: var(--panel); border: 1px solid rgba(255,255,255,.08); border-radius: 16px; box-shadow: var(--shadow); overflow: hidden; }
.modal-head { padding: 14px 16px; border-bottom: 1px solid rgba(255,255,255,.08); background: linear-gradient(135deg, rgba(255,255,255,.16), rgba(255,255,255,.08)); font-weight: 800; }
.modal-body { padding: 16px; display: grid; gap: 12px; }
.field { display: grid; gap: 6px; }
.field label { font-weight: 700; }
.input { width: 100%; padding: 10px 12px; border-radius: 10px; border: 1px solid rgba(255,255,255,.12); background: rgba(255,255,255,.06); color: var(--text); }
.help { color: var(--muted); font-size: 12px; }

/* Boards */
.tictactoe-board { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; width: min(360px, 92%); margin: 0 auto; }
.cell { width: 100%; aspect-ratio: 1/1; background: rgba(255,255,255,.04); border: 1px solid rgba(255,255,255,.08); border-radius: 12px; display: grid; place-items: center; font-size: 42px; font-weight: 800; cursor: pointer; }
.cell:hover { background: rgba(255,255,255,.07); }

.memory-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 10px; width: min(440px, 92%); margin: 0 auto; }
.card-tile { aspect-ratio: 1/1; border-radius: 12px; position: relative; transform-style: preserve-3d; transition: transform .3s; cursor: pointer; }
.card-tile .front, .card-tile .back { position: absolute; inset: 0; display: grid; place-items: center; border-radius: 12px; backface-visibility: hidden; border: 1px solid rgba(255,255,255,.08); }
.card-tile .front { background: rgba(255,255,255,.05); }
.card-tile .back { background: linear-gradient(135deg, var(--brand), var(--brand-2)); color: #000000; transform: rotateY(180deg); font-size: 28px; font-weight: 800; }
.card-tile.revealed { transform: rotateY(180deg); }

.game-canvas { background: rgba(255,255,255,.05); border: 1px solid rgba(255,255,255,.08); border-radius: 12px; width: min(520px, 95%); aspect-ratio: 1/1; display: block; margin: 0 auto; }

@media (max-width: 900px) {
  .hero-inner { grid-template-columns: 1fr; }
  .grid { grid-template-columns: 1fr; }
  .grid.two { grid-template-columns: 1fr; }
  .lesson-layout { grid-template-columns: 1fr; }
}