:root {
  --bg: #f4f6f9;
  --card: #ffffff;
  --text: #1c2430;
  --muted: #5d6878;
  --border: #d9dee6;
  --accent: #0b6fbf;
  --accent-text: #ffffff;
  --exhibit-bg: #0f1720;
  --exhibit-text: #d6e2ee;
  --ok: #1d7a3d;
  --ok-bg: #e5f4ea;
  --bad: #b3261e;
  --bad-bg: #fbe9e7;
  --sel-bg: #e6f0fa;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #11151b;
    --card: #1a2029;
    --text: #e3e8ef;
    --muted: #97a2b3;
    --border: #2d3644;
    --accent: #4ea3ea;
    --accent-text: #0b1520;
    --exhibit-bg: #0a0e13;
    --exhibit-text: #cfdbe7;
    --ok: #5ccf83;
    --ok-bg: #16301f;
    --bad: #f2867d;
    --bad-bg: #3a1c1a;
    --sel-bg: #1c3044;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
}

.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 16px;
  border-bottom: 1px solid var(--border);
  background: var(--card);
}
.brand { display: flex; gap: 10px; align-items: baseline; }
.brand-code {
  font-family: ui-monospace, Menlo, Consolas, monospace;
  font-size: 0.85rem;
  color: var(--accent);
  font-weight: 600;
}
.brand-name { font-weight: 600; }
.timer { font-family: ui-monospace, Menlo, Consolas, monospace; font-weight: 600; }
.timer.low { color: var(--bad); }

main { max-width: 860px; margin: 24px auto; padding: 0 16px; }

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 24px;
}
h1 { margin: 0 0 4px; font-size: 1.5rem; }
h2 { font-size: 1.1rem; margin: 28px 0 10px; }
.muted { color: var(--muted); }
.error { color: var(--bad); }

/* Setup */
.setup-actions { display: flex; gap: 12px; margin: 16px 0 8px; }
.link-btn {
  background: none; border: 0; padding: 0;
  color: var(--accent); cursor: pointer; font: inherit;
}
.topic-list { display: grid; gap: 16px; }
.domain h3 {
  margin: 0 0 6px; font-size: 0.95rem;
  display: flex; align-items: center; gap: 8px;
}
.domain-topics {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 4px 16px;
  padding-left: 26px;
}
.check { display: flex; gap: 8px; align-items: center; cursor: pointer; }
.check .count { color: var(--muted); font-size: 0.85rem; }

.options-row { display: grid; grid-template-columns: 1fr 2fr; gap: 24px; margin: 24px 0; }
.field { border: 0; padding: 0; margin: 0; display: flex; flex-direction: column; gap: 6px; }
.field > span, .field legend { font-weight: 600; margin-bottom: 4px; padding: 0; }
.radio { display: flex; gap: 8px; align-items: baseline; cursor: pointer; }
select {
  font: inherit; padding: 6px 8px; border-radius: 6px;
  border: 1px solid var(--border); background: var(--card); color: var(--text);
}

button.primary, button.ghost {
  font: inherit; font-weight: 600; border-radius: 6px;
  padding: 10px 20px; cursor: pointer;
}
button.primary { background: var(--accent); color: var(--accent-text); border: 1px solid var(--accent); }
button.primary:disabled { opacity: 0.45; cursor: not-allowed; }
button.ghost { background: transparent; color: var(--text); border: 1px solid var(--border); }

/* Quiz */
.progress { height: 4px; background: var(--border); border-radius: 2px; overflow: hidden; margin-bottom: 16px; }
#progress-bar { height: 100%; width: 0; background: var(--accent); transition: width 0.2s; }
.q-meta { display: flex; justify-content: space-between; align-items: center; gap: 8px; color: var(--muted); font-size: 0.9rem; }
.tag {
  border: 1px solid var(--border); border-radius: 999px;
  padding: 2px 10px; font-size: 0.8rem;
}
.q-text { font-size: 1.05rem; margin: 14px 0; white-space: pre-line; }
.exhibit { margin: 0 0 16px; border-radius: 8px; overflow: hidden; border: 1px solid var(--border); }
.exhibit-label {
  font-size: 0.75rem; font-weight: 600; text-transform: uppercase; letter-spacing: 0.05em;
  padding: 4px 12px; background: var(--border); color: var(--text);
}
.exhibit pre {
  margin: 0; padding: 12px; overflow-x: auto;
  background: var(--exhibit-bg); color: var(--exhibit-text);
  font: 0.82rem/1.45 ui-monospace, Menlo, Consolas, monospace;
}
.hint { font-weight: 600; margin: 0 0 8px; font-size: 0.9rem; color: var(--muted); }

.options { list-style: none; margin: 0; padding: 0; display: grid; gap: 8px; }
.option {
  display: flex; gap: 12px; align-items: flex-start;
  border: 1px solid var(--border); border-radius: 8px;
  padding: 10px 12px; cursor: pointer;
}
.option:hover { border-color: var(--accent); }
.option input { margin-top: 4px; }
.option .letter { font-weight: 700; min-width: 1.2em; }
.option.selected { background: var(--sel-bg); border-color: var(--accent); }
.option.correct { background: var(--ok-bg); border-color: var(--ok); }
.option.incorrect { background: var(--bad-bg); border-color: var(--bad); }
.options.locked .option { cursor: default; }
.options.locked .option:hover { border-color: inherit; }

.feedback { margin-top: 16px; padding: 12px 14px; border-radius: 8px; border-left: 4px solid; }
.feedback.ok { background: var(--ok-bg); border-color: var(--ok); }
.feedback.bad { background: var(--bad-bg); border-color: var(--bad); }
.feedback strong { display: block; margin-bottom: 4px; }

.q-actions { display: flex; justify-content: space-between; margin-top: 20px; gap: 12px; }
.kbd-hint { font-size: 0.8rem; margin: 10px 0 0; text-align: right; }

/* Results */
.score-row { display: flex; align-items: center; gap: 20px; margin: 12px 0; }
.score-big { font-size: 2.6rem; font-weight: 700; }
.verdict { font-weight: 700; font-size: 1.1rem; }
.verdict.pass { color: var(--ok); }
.verdict.fail { color: var(--bad); }
.breakdown { width: 100%; border-collapse: collapse; font-size: 0.92rem; }
.breakdown th, .breakdown td { text-align: left; padding: 6px 8px; border-bottom: 1px solid var(--border); }
.breakdown td:nth-child(n+2), .breakdown th:nth-child(n+2) { text-align: right; font-variant-numeric: tabular-nums; }
.results-actions { display: flex; gap: 12px; justify-content: flex-end; margin-top: 20px; }

.review-list { display: grid; gap: 14px; margin-top: 12px; }
.review-item { border: 1px solid var(--border); border-radius: 8px; padding: 14px; }
.review-item.wrong { border-left: 4px solid var(--bad); }
.review-item.right { border-left: 4px solid var(--ok); }
.review-item .q-text { margin: 6px 0 10px; font-size: 1rem; }
.review-item ul { margin: 0 0 10px; padding-left: 0; list-style: none; display: grid; gap: 4px; }
.review-item li { padding: 4px 8px; border-radius: 4px; }
.review-item li.correct { background: var(--ok-bg); }
.review-item li.chosen-wrong { background: var(--bad-bg); }
.review-item .explain { font-size: 0.92rem; color: var(--muted); }

footer { text-align: center; font-size: 0.8rem; padding: 16px 16px 32px; }

@media (max-width: 640px) {
  .card { padding: 16px; }
  .options-row { grid-template-columns: 1fr; }
  .domain-topics { padding-left: 0; }
  .score-row { flex-direction: column; align-items: flex-start; gap: 4px; }
}