:root {
  --bg: #0d1a2e;
  --bg-deep: #070e1c;
  --saffron: #fbbf24;
  --saffron-strong: #f59e0b;
  --text: #f1f5f9;
  --text-muted: #94a3b8;
  --green: #16a34a;
  --red: #dc2626;
  --selected-bg: #0e2740;
  --border: #1e3252;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: Inter, system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
}
#app {
  max-width: 800px;
  margin: 0 auto;
  padding: 24px 16px;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}
header {
  display: flex;
  align-items: baseline;
  gap: 16px;
  border-bottom: 2px solid var(--saffron);
  padding-bottom: 12px;
}
.brand {
  font-family: Nunito, sans-serif;
  font-weight: 800;
  color: var(--saffron);
  font-size: 24px;
}
.title { color: var(--text-muted); }
.progress {
  margin-left: auto;
  color: var(--text-muted);
  font-variant-numeric: tabular-nums;
}
main { flex: 1; padding: 24px 0; }
.meta {
  color: var(--text-muted);
  font-size: 14px;
  margin-bottom: 12px;
}
.question-text {
  font-family: Nunito, sans-serif;
  font-weight: 700;
  line-height: 1.4;
  margin: 0 0 24px 0;
  font-size: 22px;
}
.option {
  display: flex;
  gap: 12px;
  padding: 14px;
  margin-bottom: 10px;
  background: var(--bg-deep);
  border-left: 4px solid transparent;
  border-radius: 6px;
  cursor: pointer;
  align-items: flex-start;
}
.option:hover { border-left-color: var(--saffron-strong); }
.option.selected {
  border-left-color: var(--saffron);
  background: var(--selected-bg);
}
.option input { margin-top: 4px; }
.option .letter {
  font-weight: 700;
  color: var(--saffron);
  min-width: 24px;
}
.option .text-content { flex: 1; }
footer {
  display: flex;
  gap: 12px;
  padding-top: 12px;
  border-top: 1px solid var(--border);
}
button {
  padding: 10px 20px;
  background: var(--saffron);
  color: var(--bg);
  font-weight: 700;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  font-family: Nunito, sans-serif;
  font-size: 14px;
}
button:disabled { opacity: 0.4; cursor: not-allowed; }
#submit-btn {
  margin-left: auto;
  background: var(--green);
  color: white;
}
#result-area { padding: 24px 0; }
.result-header {
  font-family: Nunito, sans-serif;
  font-size: 32px;
  margin: 0 0 8px 0;
}
.result-header.pass { color: var(--green); }
.result-header.fail { color: var(--red); }
.result-sub { color: var(--text-muted); margin-bottom: 24px; }
.review-item {
  padding: 16px;
  margin-bottom: 12px;
  background: var(--bg-deep);
  border-left: 4px solid var(--border);
  border-radius: 6px;
}
.review-item.right { border-left-color: var(--green); }
.review-item.wrong { border-left-color: var(--red); }
.review-q { margin: 0 0 8px 0; }
.review-meta { color: var(--text-muted); font-size: 14px; }
.review-explain {
  color: var(--text-muted);
  font-size: 14px;
  margin: 8px 0 0 0;
}
.error-message {
  color: var(--red);
  padding: 16px;
  background: var(--bg-deep);
  border-left: 4px solid var(--red);
  border-radius: 6px;
}
@media (max-width: 480px) {
  #app { padding: 16px 12px; }
  .question-text { font-size: 18px; }
  .option { font-size: 14px; padding: 12px; }
}