:root {
  --bg: #0f172a;
  --surface: #1e293b;
  --surface-2: #273449;
  --border: #334155;
  --text: #e2e8f0;
  --muted: #94a3b8;
  --primary: #6366f1;
  --primary-hover: #4f46e5;
  --success: #10b981;
  --success-bg: rgba(16, 185, 129, 0.12);
  --error: #ef4444;
  --error-bg: rgba(239, 68, 68, 0.12);
  --accent: #f59e0b;
}

* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.55;
}

.container {
  max-width: 820px;
  margin: 0 auto;
  padding: 32px 20px 80px;
}

.hero {
  text-align: center;
  padding: 32px 16px 24px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 28px;
}

.hero h1 {
  margin: 0 0 6px;
  font-size: 2rem;
  letter-spacing: -0.02em;
}

.subtitle {
  margin: 0 0 14px;
  color: var(--muted);
}

.weights {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: center;
}

.badge {
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--muted);
  padding: 4px 12px;
  border-radius: 999px;
  font-size: 0.8rem;
}

.badge-strong {
  background: var(--primary);
  color: white;
  border-color: var(--primary);
}

.question-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px 22px;
  margin-bottom: 16px;
  transition: border-color 0.2s ease;
}

.question-card.is-correct {
  border-color: var(--success);
  background: var(--success-bg);
}

.question-card.is-wrong {
  border-color: var(--error);
  background: var(--error-bg);
}

.q-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.78rem;
  color: var(--muted);
  margin-bottom: 8px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.q-chapter {
  color: var(--accent);
  font-weight: 600;
}

.q-text {
  margin: 0 0 14px;
  font-size: 1.05rem;
  font-weight: 500;
}

.options {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.option {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 14px;
  cursor: pointer;
  transition: border-color 0.15s ease, background 0.15s ease;
}

.option:hover {
  border-color: var(--primary);
}

.option input[type="radio"] {
  margin-top: 4px;
  accent-color: var(--primary);
  flex-shrink: 0;
}

.option.option-correct {
  border-color: var(--success);
  background: var(--success-bg);
}

.option.option-wrong {
  border-color: var(--error);
  background: var(--error-bg);
}

.option .option-text {
  flex: 1;
}

.option .option-mark {
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  white-space: nowrap;
}

.option.option-correct .option-mark { color: var(--success); }
.option.option-wrong .option-mark { color: var(--error); }

.feedback {
  margin-top: 12px;
  padding: 10px 12px;
  border-radius: 8px;
  font-size: 0.9rem;
  background: rgba(255, 255, 255, 0.04);
  border-left: 3px solid var(--accent);
  display: none;
}

.feedback.show { display: block; }

.actions {
  display: flex;
  gap: 12px;
  justify-content: center;
  margin-top: 24px;
}

.btn {
  font: inherit;
  border-radius: 8px;
  padding: 12px 24px;
  border: 1px solid transparent;
  cursor: pointer;
  font-weight: 600;
  transition: background 0.15s ease, transform 0.1s ease;
}

.btn:active { transform: translateY(1px); }

.btn-primary {
  background: var(--primary);
  color: white;
}

.btn-primary:hover {
  background: var(--primary-hover);
}

.btn-ghost {
  background: transparent;
  color: var(--muted);
  border-color: var(--border);
}

.btn-ghost:hover {
  color: var(--text);
  border-color: var(--text);
}

.score-banner {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px 24px;
  margin-bottom: 24px;
  text-align: center;
}

.score-banner.pass { border-color: var(--success); }
.score-banner.fail { border-color: var(--error); }

.score-banner h2 {
  margin: 0 0 6px;
  font-size: 1.6rem;
}

.score-banner .score-percent {
  color: var(--accent);
  font-size: 2.2rem;
  font-weight: 700;
}

.score-banner .score-detail {
  color: var(--muted);
  font-size: 0.95rem;
  margin: 6px 0 0;
}

.score-breakdown {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: center;
  margin-top: 12px;
}

.score-breakdown span {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 4px 12px;
  font-size: 0.82rem;
  color: var(--muted);
}

.hidden { display: none; }