:root {
  --bg: #0f1214;
  --fg: #e5e7eb;
  --muted: #9ca3af;
  --brand: #22c55e;
  --card: #171a1c;
  --accent: #3b82f6;
}
* { box-sizing: border-box; }
body {
  margin: 0; font-family: system-ui, -apple-system, Segoe UI, Roboto, Inter, sans-serif;
  background: var(--bg); color: var(--fg);
}
#app { max-width: 800px; margin: 0 auto; padding: 20px; }
header h1 { margin: 0 0 4px; font-size: 22px; }
.muted { color: var(--muted); margin: 0 0 16px; }

#quiz-list { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 12px; }
.card {
  background: var(--card); padding: 14px; border-radius: 14px; border: 1px solid #22272a;
}
.card h3 { margin: 0 0 8px; font-size: 18px; }
.badge { display: inline-block; padding: 2px 8px; border-radius: 999px; background: #111418; color: var(--muted); font-size: 12px; border: 1px solid #1f2428; }
button {
  background: var(--accent); color: white; border: none; padding: 10px 14px; border-radius: 10px; cursor: pointer; font-weight: 600;
}
button.ghost { background: transparent; color: var(--fg); border: 1px solid #2b3035; }
button:disabled { opacity: 0.6; cursor: not-allowed; }
.hidden { display: none; }

.q { background: var(--card); padding: 16px; border-radius: 12px; border: 1px solid #22272a; margin-bottom: 10px; }
.q h4 { margin: 0 0 10px; }
.opt { display: block; padding: 10px; border-radius: 10px; border: 1px solid #2b3035; margin: 8px 0; cursor: pointer; }
.opt.selected { border-color: var(--accent); background: rgba(59,130,246,0.1); }
.opt.correct { border-color: #16a34a; }
.opt.incorrect { border-color: #dc2626; }
.exp { color: var(--muted); margin-top: 6px; font-size: 14px; }
#nav { display: flex; gap: 8px; margin-top: 10px; }