:root {
  --bg: #0b1020;
  --card: #121a33;
  --text: #e9ecf1;
  --muted: #a8b0c2;
  --accent: #5eead4;
  --danger: #fb7185;
  --ok: #34d399;
  --border: rgba(255,255,255,.10);
}

* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
  background: radial-gradient(1200px 600px at 20% 0%, #101a3a, var(--bg));
  color: var(--text);
}

.wrap { max-width: 1100px; margin: 0 auto; padding: 20px; }
.grid { display: grid; grid-template-columns: 1fr 1.4fr; gap: 16px; }
@media (max-width: 900px) { .grid { grid-template-columns: 1fr; } }

.card {
  background: rgba(18,26,51,.95);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 16px;
  box-shadow: 0 12px 40px rgba(0,0,0,.35);
}

h1 { margin: 0 0 6px; font-size: 28px; }
h2 { margin: 0 0 10px; font-size: 18px; }
h3 { margin: 14px 0 10px; font-size: 16px; }

.muted { color: var(--muted); }
.row { display: flex; align-items: center; justify-content: space-between; gap: 12px; }

select, button {
  border-radius: 10px;
  border: 1px solid var(--border);
  background: rgba(255,255,255,.06);
  color: var(--text);
  padding: 10px 12px;
  font-size: 14px;
}

button { cursor: pointer; }
button:disabled { opacity: .5; cursor: not-allowed; }
button.ghost { background: transparent; }

.topicList { list-style: none; padding: 0; margin: 0; display: grid; gap: 10px; }
.topicList button {
  width: 100%;
  text-align: left;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.pill {
  border: 1px solid var(--border);
  padding: 6px 10px;
  border-radius: 999px;
  font-size: 12px;
  color: var(--accent);
}

.progressBox { margin: 14px 0; padding: 12px; border: 1px solid var(--border); border-radius: 12px; }
.bar { height: 10px; background: rgba(255,255,255,.08); border-radius: 999px; overflow: hidden; }
#barFill { height: 100%; width: 0%; background: linear-gradient(90deg, var(--accent), #60a5fa); }

.lesson { line-height: 1.55; }
.lesson .box { border: 1px solid var(--border); border-radius: 12px; padding: 12px; margin: 10px 0; background: rgba(255,255,255,.04); }
.lesson code { background: rgba(255,255,255,.08); padding: 2px 6px; border-radius: 8px; }

.quiz { margin-top: 10px; }
.qText { font-size: 16px; margin: 8px 0 12px; }
.choices { display: grid; gap: 10px; }
.choice {
  padding: 12px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: rgba(255,255,255,.05);
  text-align: left;
}
.choice.correct { border-color: rgba(52,211,153,.7); }
.choice.wrong { border-color: rgba(251,113,133,.7); }

.feedback { margin-top: 10px; min-height: 22px; }
.feedback.ok { color: var(--ok); }
.feedback.bad { color: var(--danger); }