/* ============================================================
   Quiz App — 样式
   ============================================================ */

/* --- Reset & Base --- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --primary: #4f46e5;
  --primary-light: #818cf8;
  --primary-dark: #3730a3;
  --success: #10b981;
  --success-light: #d1fae5;
  --danger: #ef4444;
  --danger-light: #fee2e2;
  --warning: #f59e0b;
  --warning-light: #fef3c7;
  --info: #6366f1;
  --gray-50: #f9fafb;
  --gray-100: #f3f4f6;
  --gray-200: #e5e7eb;
  --gray-300: #d1d5db;
  --gray-400: #9ca3af;
  --gray-500: #6b7280;
  --gray-600: #4b5563;
  --gray-700: #374151;
  --gray-800: #1f2937;
  --gray-900: #111827;
  --radius: 10px;
  --shadow: 0 1px 3px rgba(0,0,0,0.1), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -2px rgba(0,0,0,0.05);
  --transition: 0.2s ease;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  min-height: 100vh;
  color: var(--gray-800);
  line-height: 1.6;
}

/* --- Container --- */
.container {
  max-width: 800px;
  margin: 0 auto;
  padding: 20px 16px 40px;
}

/* --- Header --- */
.header {
  text-align: center;
  padding: 30px 20px 20px;
  color: #fff;
}
.header h1 {
  font-size: 2rem;
  font-weight: 800;
  letter-spacing: 1px;
}
.header p {
  margin-top: 6px;
  opacity: 0.85;
  font-size: 0.95rem;
}

/* --- Card --- */
.card {
  background: #fff;
  border-radius: var(--radius);
  box-shadow: var(--shadow-lg);
  padding: 24px;
  margin-bottom: 20px;
}

/* --- Controls Bar --- */
.controls {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
}
.controls label {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--gray-600);
  display: flex;
  align-items: center;
  gap: 8px;
}
.controls select,
.controls input[type="number"] {
  padding: 8px 12px;
  border: 1px solid var(--gray-300);
  border-radius: 8px;
  font-size: 0.9rem;
  background: #fff;
  color: var(--gray-800);
  outline: none;
  transition: border-color var(--transition);
}
.controls select:focus,
.controls input[type="number"]:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(79,70,229,0.15);
}
.controls input[type="number"] { width: 80px; }

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 20px;
  border: none;
  border-radius: 8px;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
  text-decoration: none;
}
.btn:active { transform: scale(0.97); }
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); }
.btn-success { background: var(--success); color: #fff; }
.btn-success:hover { background: #059669; }
.btn-outline {
  background: transparent;
  color: var(--primary);
  border: 2px solid var(--primary);
}
.btn-outline:hover { background: var(--primary); color: #fff; }
.btn-danger { background: var(--danger); color: #fff; }
.btn-danger:hover { background: #dc2626; }
.btn:disabled { opacity: 0.5; cursor: not-allowed; transform: none; }
.btn-sm { padding: 6px 14px; font-size: 0.85rem; }

/* --- Timer Bar --- */
.timer-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 16px;
  background: var(--gray-50);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius);
  margin-bottom: 20px;
}
.timer-display {
  font-size: 1.5rem;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  color: var(--primary);
}
.timer-display.warning { color: var(--warning); }
.timer-display.danger { color: var(--danger); animation: pulse 1s infinite; }
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}
.timer-status { font-size: 0.85rem; color: var(--gray-500); }

/* --- Start Bar --- */
.start-bar-inner { text-align: center; padding: 20px 0; }
.start-bar-inner p { color: var(--gray-500); margin-bottom: 16px; }
.start-bar-inner button { font-size: 1.1rem; padding: 12px 32px; }

/* --- Section Title --- */
.section-title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--gray-700);
  margin: 24px 0 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--gray-200);
  display: flex;
  align-items: center;
  gap: 8px;
}
.section-title .badge {
  font-size: 0.75rem;
  background: var(--primary-light);
  color: #fff;
  padding: 2px 10px;
  border-radius: 12px;
  font-weight: 600;
}

/* --- Question Item --- */
.question-item {
  padding: 16px 0;
  border-bottom: 1px solid var(--gray-100);
}
.question-item:last-child { border-bottom: none; }

.q-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--primary);
  color: #fff;
  font-size: 0.8rem;
  font-weight: 700;
  margin-right: 8px;
  flex-shrink: 0;
}
.q-text {
  font-size: 1rem;
  font-weight: 600;
  color: var(--gray-800);
  margin-bottom: 12px;
  display: flex;
  align-items: flex-start;
  gap: 4px;
}
.q-tag {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: 4px;
  margin-left: 8px;
  vertical-align: middle;
}
.q-tag.multi { background: #ede9fe; color: var(--primary-dark); }
.q-tag.single { background: #dbeafe; color: #1d4ed8; }

/* --- Options --- */
.options {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding-left: 36px;
}
.option-label {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 14px;
  border: 1px solid var(--gray-200);
  border-radius: 8px;
  cursor: pointer;
  transition: all var(--transition);
  font-size: 0.95rem;
  background: var(--gray-50);
}
.option-label:hover {
  border-color: var(--primary-light);
  background: #eef2ff;
}
.option-label input[type="checkbox"] {
  width: 18px;
  height: 18px;
  accent-color: var(--primary);
  cursor: pointer;
  flex-shrink: 0;
}
.option-label.selected {
  border-color: var(--primary);
  background: #eef2ff;
}

/* --- Free Answer Input --- */
.free-input { padding-left: 36px; }
.free-input input {
  width: 100%;
  padding: 10px 14px;
  border: 1px solid var(--gray-300);
  border-radius: 8px;
  font-size: 0.95rem;
  outline: none;
  transition: border-color var(--transition);
  background: var(--gray-50);
}
.free-input input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(79,70,229,0.15);
}
.free-input input:disabled { background: var(--gray-100); color: var(--gray-500); }
.option-label input:disabled { opacity: 0.6; }

/* --- Action Bar --- */
.action-bar { display: flex; flex-wrap: wrap; gap: 12px; }
.action-bar-inner {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 20px;
  padding-top: 20px;
  border-top: 1px solid var(--gray-200);
}

/* --- Results --- */
.result-header { text-align: center; padding: 20px 0; }
.result-score {
  font-size: 3rem;
  font-weight: 800;
  color: var(--primary);
}
.result-score-label { font-size: 1rem; color: var(--gray-500); }
.result-note { text-align: center; color: var(--gray-400); font-size: 0.85rem; margin-bottom: 16px; }

/* --- Result Item --- */
.result-item {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 12px 0;
  border-bottom: 1px solid var(--gray-100);
}
.result-item:last-child { border-bottom: none; }
.result-icon { font-size: 1.2rem; flex-shrink: 0; margin-top: 2px; }
.result-q-text { flex: 1; font-size: 0.95rem; }
.result-q-text .correct-answer {
  display: block;
  margin-top: 4px;
  font-size: 0.85rem;
  color: var(--success);
  font-weight: 600;
}
.result-q-text .your-answer {
  display: block;
  font-size: 0.85rem;
  color: var(--gray-500);
}
.result-q-text .your-answer.wrong { color: var(--danger); }
.result-q-text .partial-score {
  font-size: 0.8rem;
  color: var(--warning);
  font-weight: 600;
}

/* --- Share Box --- */
.share-box {
  margin-top: 16px;
  padding: 12px;
  background: var(--gray-50);
  border: 1px solid var(--gray-200);
  border-radius: 8px;
  display: flex;
  gap: 8px;
  align-items: center;
}
.share-box input {
  flex: 1;
  border: none;
  background: transparent;
  font-size: 0.82rem;
  color: var(--gray-600);
  outline: none;
  padding: 4px;
}
.share-box .btn { flex-shrink: 0; }
.share-hint { font-size: 0.8rem; color: var(--gray-400); margin-top: 8px; }

/* --- Toast --- */
.toast {
  position: fixed;
  top: 20px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--gray-800);
  color: #fff;
  padding: 12px 24px;
  border-radius: 8px;
  font-size: 0.9rem;
  z-index: 1000;
  opacity: 0;
  transition: opacity 0.3s ease;
  pointer-events: none;
}
.toast.show { opacity: 1; }

/* --- Footer --- */
.footer {
  text-align: center;
  padding: 20px;
  color: rgba(255,255,255,0.6);
  font-size: 0.8rem;
}

/* --- Responsive --- */
@media (max-width: 600px) {
  .container { padding: 12px 8px 24px; }
  .card { padding: 16px; }
  .header h1 { font-size: 1.5rem; }
  .controls { flex-direction: column; align-items: stretch; }
  .controls label { justify-content: space-between; }
  .controls .btn { width: 100%; justify-content: center; }
  .action-bar-inner { flex-direction: column; }
  .action-bar-inner .btn { width: 100%; justify-content: center; }
  .result-score { font-size: 2.2rem; }
  .options { padding-left: 0; }
  .free-input { padding-left: 0; }
  .share-box { flex-direction: column; }
}

/* --- Empty State --- */
.empty-state { text-align: center; padding: 40px 20px; color: var(--gray-400); }
.empty-state .icon { font-size: 3rem; margin-bottom: 12px; }
.empty-state p { font-size: 0.95rem; }

/* --- Hidden --- */
.hidden { display: none !important; }