:root {
  --bg-color: #fef9f0;
  --card-bg: #ffffff;
  --text-color: #2e2516;
  --text-secondary: #8a7a5d;
  --border-color: #f1e6d0;
  --primary-color: #f59e0b;
  --primary-hover: #d97706;
  --accent-amber: #fbbf24;
  --accent-orange: #fb923c;
  --accent-red: #f87171;
  --accent-green: #34d399;
  --accent-blue: #60a5fa;
  --accent-purple: #c084fc;
  --accent-pink: #f472b6;
  --shadow: 0 4px 16px rgba(245, 158, 11, 0.12);
  --shadow-hover: 0 8px 28px rgba(245, 158, 11, 0.22);
}

[data-theme="dark"] {
  --bg-color: #1a1408;
  --card-bg: #272010;
  --text-color: #fef3c7;
  --text-secondary: #a89569;
  --border-color: #3d2f16;
  --primary-color: #fbbf24;
  --primary-hover: #f59e0b;
  --shadow: 0 4px 16px rgba(0,0,0,0.4);
  --shadow-hover: 0 8px 28px rgba(251, 191, 36, 0.25);
}

* { margin:0; padding:0; box-sizing:border-box; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg-color);
  color: var(--text-color);
  line-height: 1.7;
  transition: background 0.3s, color 0.3s;
}

.container { max-width: 1200px; margin: 0 auto; padding: 0 16px; }

.header {
  background: var(--card-bg);
  box-shadow: var(--shadow);
  position: sticky;
  top: 0;
  z-index: 100;
  border-bottom: 2px solid var(--primary-color);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 16px;
  flex-wrap: wrap;
  gap: 12px;
}

.logo {
  font-size: 22px;
  font-weight: 800;
  color: var(--primary-color);
}

.header-actions { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; }

.search-box { display: flex; border: 1px solid var(--border-color); border-radius: 12px; overflow: hidden; background: var(--bg-color); }
.search-box input {
  border: none;
  outline: none;
  padding: 10px 14px;
  font-size: 14px;
  background: transparent;
  color: var(--text-color);
  width: 220px;
}
.search-box button {
  border: none;
  background: var(--primary-color);
  color: #fff;
  padding: 0 18px;
  cursor: pointer;
  transition: background 0.2s;
}
.search-box button:hover { background: var(--primary-hover); }

.theme-btn {
  border: 1px solid var(--border-color);
  background: var(--bg-color);
  width: 42px;
  height: 42px;
  border-radius: 12px;
  cursor: pointer;
  font-size: 18px;
  color: var(--text-color);
  transition: all 0.2s;
}
.theme-btn:hover { transform: scale(1.05); }

.nav { border-top: 1px solid var(--border-color); background: var(--card-bg); }
.nav-inner { display: flex; gap: 8px; padding: 12px 16px; overflow-x: auto; scrollbar-width: none; }
.nav-inner::-webkit-scrollbar { display: none; }
.cat-btn {
  padding: 8px 16px;
  border: 1px solid var(--border-color);
  background: var(--bg-color);
  color: var(--text-color);
  border-radius: 22px;
  cursor: pointer;
  white-space: nowrap;
  font-size: 14px;
  transition: all 0.2s;
}
.cat-btn:hover { border-color: var(--primary-color); color: var(--primary-color); }
.cat-btn.active { background: var(--primary-color); color: #fff; border-color: var(--primary-color); font-weight: 600; }

.main { padding: 24px 16px; min-height: calc(100vh - 220px); }

.hero { margin-bottom: 26px; }
.hero-card {
  background: linear-gradient(135deg, rgba(245,158,11,0.18), rgba(251,146,60,0.14));
  border: 1px solid rgba(245,158,11,0.35);
  border-radius: 18px;
  padding: 26px 28px;
  display: flex;
  gap: 22px;
  align-items: flex-start;
}
.hero-icon {
  font-size: 54px;
  line-height: 1;
  flex-shrink: 0;
  filter: drop-shadow(0 4px 10px rgba(245,158,11,0.35));
  animation: bounce 2.4s ease-in-out infinite;
}
@keyframes bounce {
  0%,100% { transform: translateY(0) rotate(-4deg); }
  50%     { transform: translateY(-10px) rotate(4deg); }
}
#dailyTitle {
  font-size: 17px;
  color: var(--primary-color);
  font-weight: 700;
  margin-bottom: 8px;
  letter-spacing: 1px;
}
#dailyFact {
  font-size: 18px;
  color: var(--text-color);
  font-weight: 500;
  line-height: 1.75;
  margin-bottom: 14px;
}
.another-btn {
  padding: 9px 20px;
  border: none;
  background: var(--primary-color);
  color: #fff;
  border-radius: 22px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
}
.another-btn:hover { background: var(--primary-hover); transform: translateY(-1px); }

.stats-bar {
  display: flex;
  justify-content: space-between;
  padding: 12px 18px;
  background: var(--card-bg);
  border-radius: 12px;
  margin-bottom: 20px;
  font-size: 14px;
  color: var(--text-secondary);
  border: 1px solid var(--border-color);
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 20px;
}

.fact-card {
  background: var(--card-bg);
  border-radius: 16px;
  padding: 22px;
  box-shadow: var(--shadow);
  transition: all 0.28s;
  display: flex;
  flex-direction: column;
  border: 1px solid var(--border-color);
  cursor: pointer;
  position: relative;
  overflow: hidden;
}
.fact-card:hover {
  box-shadow: var(--shadow-hover);
  transform: translateY(-3px);
}

.fact-icon {
  font-size: 38px;
  margin-bottom: 12px;
  line-height: 1;
  display: inline-block;
}

.fact-tag {
  display: inline-block;
  padding: 4px 12px;
  font-size: 12px;
  border-radius: 14px;
  margin-bottom: 12px;
  align-self: flex-start;
  color: #fff;
  font-weight: 600;
  letter-spacing: 0.5px;
}
.fact-tag.科学 { background: #3b82f6; }
.fact-tag.历史 { background: #a16207; }
.fact-tag.动物 { background: #059669; }
.fact-tag.人体 { background: #dc2626; }
.fact-tag.食物 { background: #ea580c; }
.fact-tag.宇宙 { background: #7c3aed; }
.fact-tag.生活 { background: #0891b2; }

.fact-title {
  font-size: 16px;
  font-weight: 700;
  margin-bottom: 10px;
  line-height: 1.45;
}

.fact-preview {
  font-size: 14px;
  color: var(--text-secondary);
  flex: 1;
  display: -webkit-box;
  -webkit-line-clamp: 4;
  -webkit-box-orient: vertical;
  overflow: hidden;
  margin-bottom: 14px;
}

.fact-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 12px;
  border-top: 1px dashed var(--border-color);
  font-size: 12px;
  color: var(--text-secondary);
}
.fact-footer .views { color: var(--primary-color); font-weight: 600; }

.empty-state, .loading-state {
  text-align: center;
  padding: 80px 20px;
  color: var(--text-secondary);
  font-size: 16px;
}
.spinner {
  width: 42px;
  height: 42px;
  border: 4px solid var(--border-color);
  border-top-color: var(--primary-color);
  border-radius: 50%;
  margin: 0 auto 16px;
  animation: spin 0.8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }


.modal {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 200;
  align-items: center;
  justify-content: center;
  padding: 20px;
}
.modal.open { display: flex; }
.modal-mask {
  position: absolute;
  inset: 0;
  background: rgba(0,0,0,0.6);
  backdrop-filter: blur(4px);
}
.modal-content {
  position: relative;
  background: var(--card-bg);
  border-radius: 20px;
  padding: 34px 32px;
  max-width: 620px;
  width: 100%;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: 0 18px 60px rgba(0,0,0,0.45);
  border: 1px solid var(--border-color);
}
.modal-close {
  position: absolute;
  top: 14px; right: 14px;
  background: var(--bg-color);
  color: var(--text-secondary);
  border: 1px solid var(--border-color);
  font-size: 18px;
  cursor: pointer;
  width: 38px; height: 38px;
  border-radius: 50%;
  transition: all 0.2s;
}
.modal-close:hover { background: var(--primary-color); color: #fff; border-color: transparent; transform: rotate(90deg); }

.modal-icon { font-size: 56px; text-align: center; margin-bottom: 10px; line-height: 1; }
.modal-tag {
  text-align: center;
  margin-bottom: 14px;
}
.modal-tag span {
  display: inline-block;
  padding: 4px 14px;
  font-size: 13px;
  border-radius: 14px;
  color: #fff;
  font-weight: 600;
  background: var(--primary-color);
}
#modalTitle {
  font-size: 22px;
  font-weight: 700;
  line-height: 1.5;
  text-align: center;
  margin-bottom: 18px;
}
#modalContent {
  font-size: 16px;
  line-height: 2;
  color: var(--text-color);
  margin-bottom: 22px;
}
.modal-meta {
  display: flex;
  justify-content: space-between;
  padding: 14px 18px;
  background: var(--bg-color);
  border-radius: 12px;
  font-size: 13px;
  color: var(--text-secondary);
}
.modal-meta span:last-child { color: var(--primary-color); font-weight: 600; }

@media (max-width: 720px) {
  .search-box input { width: 140px; }
  .card-grid { grid-template-columns: 1fr; }
  .stats-bar { flex-direction: column; gap: 6px; text-align: center; }
  .logo { font-size: 18px; }
  .hero-card { flex-direction: column; padding: 20px; gap: 12px; }
  .hero-icon { font-size: 46px; }
  #dailyFact { font-size: 16px; }
  .modal-content { padding: 26px 20px; }
  #modalTitle { font-size: 19px; }
  #modalContent { font-size: 15px; line-height: 1.85; }
}