:root {
  color-scheme: light dark;
  --bg: #f4f4f5;
  --card-bg: #ffffff;
  --text: #1a1a1a;
  --muted: #6b6b6b;
  --accent: #2563eb;
  --correct: #16a34a;
  --wrong: #dc2626;
  --border: #e2e2e2;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--text);
  display: flex;
  justify-content: center;
  min-height: 100vh;
  padding: 8px;
  font-size: 14px;
}

.app {
  width: 100%;
  max-width: 380px;
}

.tabs {
  display: flex;
  gap: 6px;
  margin-bottom: 10px;
}

.tab-btn {
  flex: 1;
  padding: 6px 4px;
  border: none;
  border-radius: 8px;
  background: var(--card-bg);
  color: var(--muted);
  font-size: 0.75rem;
  font-weight: 600;
  cursor: pointer;
}

.tab-btn.active {
  background: var(--accent);
  color: #fff;
}

.tab-btn:disabled {
  cursor: default;
  opacity: 0.5;
}

.scoreboard {
  display: flex;
  justify-content: space-around;
  margin-bottom: 10px;
}

.stat {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.stat-value {
  font-size: 1.1rem;
  font-weight: 700;
}

.stat-label {
  font-size: 0.65rem;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.card {
  background: var(--card-bg);
  border-radius: 12px;
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
  padding: 12px;
}

.photo-wrap {
  width: 100%;
  aspect-ratio: 1 / 1;
  border-radius: 10px;
  overflow: hidden;
  background: var(--bg);
  margin-bottom: 10px;
}

.photo-wrap img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.question {
  text-align: center;
  font-weight: 600;
  font-size: 0.85rem;
  margin: 0 0 10px;
}

.options {
  display: flex;
  flex-wrap: nowrap;
  gap: 6px;
  overflow-x: auto;
  padding-bottom: 2px;
}

.option-btn {
  flex: 1 1 0;
  min-width: 0;
  padding: 8px 4px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--card-bg);
  color: var(--text);
  font-size: 0.72rem;
  line-height: 1.15;
  text-align: center;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s;
}

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

.option-btn:disabled {
  cursor: default;
}

.option-btn.correct {
  border-color: var(--correct);
  background: color-mix(in srgb, var(--correct) 12%, var(--card-bg));
}

.option-btn.wrong {
  border-color: var(--wrong);
  background: color-mix(in srgb, var(--wrong) 12%, var(--card-bg));
}

.source-note {
  color: var(--muted);
  font-size: 0.65rem;
  text-align: center;
  margin: 6px 0 0;
}

.feedback {
  margin-top: 10px;
  text-align: center;
}

.feedback-result {
  font-size: 0.95rem;
  font-weight: 700;
  margin: 0 0 4px;
}

.feedback-result.correct {
  color: var(--correct);
}

.feedback-result.wrong {
  color: var(--wrong);
}

.feedback-details {
  color: var(--muted);
  font-size: 0.8rem;
  margin: 0 0 10px;
}

.next-btn {
  padding: 8px 20px;
  border: none;
  border-radius: 8px;
  background: var(--accent);
  color: #fff;
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #17171a;
    --card-bg: #232326;
    --text: #f0f0f0;
    --muted: #a0a0a0;
    --border: #3a3a3d;
  }
}