/* AI Research Efficiency Tracker - Styles */
:root {
  --bg: #0f1117;
  --surface: #1a1d27;
  --surface2: #242836;
  --border: #2d3148;
  --text: #e4e6f0;
  --text2: #9ca0b8;
  --accent: #6c8cff;
  --accent2: #4a6adf;
  --green: #4ade80;
  --orange: #fb923c;
  --red: #f87171;
  --purple: #a78bfa;
  --cyan: #22d3ee;
  --pink: #f472b6;
  --radius: 12px;
  --shadow: 0 2px 8px rgba(0,0,0,0.3);
}
* { margin: 0; padding: 0; box-sizing: border-box; }
body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* Navigation */
.nav {
  position: sticky; top: 0; z-index: 100;
  background: rgba(15, 17, 23, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  padding: 0 2rem;
}
.nav-inner {
  max-width: 1200px; margin: 0 auto;
  display: flex; align-items: center; justify-content: space-between;
  height: 56px;
}
.nav-logo {
  font-size: 1.1rem; font-weight: 700; color: var(--text);
  display: flex; align-items: center; gap: 0.5rem;
}
.nav-logo span { color: var(--accent); }
.nav-links { display: flex; gap: 1.5rem; list-style: none; }
.nav-links a {
  color: var(--text2); font-size: 0.9rem;
  padding: 0.4rem 0; border-bottom: 2px solid transparent;
  transition: all 0.2s;
}
.nav-links a:hover, .nav-links a.active {
  color: var(--text); border-bottom-color: var(--accent); text-decoration: none;
}

/* Container */
.container { max-width: 1200px; margin: 0 auto; padding: 2rem; }

/* Hero */
.hero { text-align: center; padding: 3rem 0 2rem; }
.hero h1 {
  font-size: 2.2rem; font-weight: 800; margin-bottom: 0.5rem;
  background: linear-gradient(135deg, var(--accent), var(--purple));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
}
.hero p { color: var(--text2); font-size: 1.05rem; }

/* Stats Grid */
.stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1rem; margin: 2rem 0; }
.stat-card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 1.5rem; text-align: center;
  transition: transform 0.2s, border-color 0.2s;
}
.stat-card:hover { transform: translateY(-2px); border-color: var(--accent); }
.stat-number { font-size: 2rem; font-weight: 800; color: var(--accent); }
.stat-label { font-size: 0.85rem; color: var(--text2); margin-top: 0.3rem; }

/* Section Headers */
.section-header {
  display: flex; align-items: center; justify-content: space-between;
  margin: 2.5rem 0 1rem; padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border);
}
.section-header h2 { font-size: 1.3rem; font-weight: 700; }
.section-header .more-link { font-size: 0.85rem; color: var(--text2); }

/* Category Cards */
.category-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 1rem;
}
.category-card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 1.2rem; cursor: pointer;
  transition: all 0.2s; display: flex; align-items: center; gap: 1rem;
  text-decoration: none; color: var(--text);
}
.category-card:hover {
  transform: translateY(-2px); border-color: var(--accent);
  box-shadow: var(--shadow); text-decoration: none;
}
.category-icon {
  width: 48px; height: 48px; border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  font-size: 1.5rem; flex-shrink: 0;
}
.category-info h3 { font-size: 1rem; font-weight: 600; margin-bottom: 0.2rem; }
.category-count { font-size: 0.8rem; color: var(--text2); }

/* Case Cards */
.case-list { display: flex; flex-direction: column; gap: 0.75rem; }
.case-card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 1.2rem;
  transition: all 0.2s;
}
.case-card:hover { border-color: var(--accent); box-shadow: var(--shadow); }
.case-card-header {
  display: flex; align-items: flex-start; justify-content: space-between; gap: 1rem;
}
.case-card h3 { font-size: 0.95rem; font-weight: 600; line-height: 1.4; }
.case-card h3 a { color: var(--text); }
.case-card h3 a:hover { color: var(--accent); }
.case-meta { display: flex; gap: 0.75rem; margin-top: 0.5rem; flex-wrap: wrap; }
.case-tag {
  font-size: 0.75rem; padding: 0.15rem 0.5rem; border-radius: 4px;
  background: var(--surface2); color: var(--text2);
}
.case-date { font-size: 0.8rem; color: var(--text2); white-space: nowrap; }
.case-metrics { display: flex; gap: 0.5rem; margin-top: 0.75rem; flex-wrap: wrap; }
.metric {
  font-size: 0.78rem; color: var(--green);
  background: rgba(74, 222, 128, 0.1); padding: 0.2rem 0.6rem; border-radius: 4px;
}

/* Tabs */
.tabs { display: flex; gap: 0.5rem; margin-bottom: 1.5rem; flex-wrap: wrap; }
.tab {
  padding: 0.5rem 1rem; border-radius: 8px; font-size: 0.85rem;
  cursor: pointer; background: var(--surface); border: 1px solid var(--border);
  color: var(--text2); transition: all 0.2s;
}
.tab:hover { border-color: var(--accent); color: var(--text); }
.tab.active { background: var(--accent); border-color: var(--accent); color: #fff; }

/* Search */
.search-box {
  width: 100%; padding: 0.75rem 1rem;
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); color: var(--text); font-size: 0.9rem;
  outline: none; margin-bottom: 1.5rem; transition: border-color 0.2s;
}
.search-box:focus { border-color: var(--accent); }
.search-box::placeholder { color: var(--text2); }

/* Daily Timeline */
.timeline { position: relative; padding-left: 2rem; }
.timeline::before {
  content: ''; position: absolute; left: 0.5rem; top: 0; bottom: 0;
  width: 2px; background: var(--border);
}
.timeline-item { position: relative; margin-bottom: 1.5rem; }
.timeline-dot {
  position: absolute; left: -1.75rem; top: 0.5rem;
  width: 10px; height: 10px; border-radius: 50%;
  background: var(--accent); border: 2px solid var(--bg);
}
.timeline-date {
  font-size: 0.85rem; color: var(--accent); font-weight: 600; margin-bottom: 0.5rem;
}
.timeline-content {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 1.2rem;
}
.timeline-content h3 { font-size: 1rem; margin-bottom: 0.75rem; }
.timeline-items { list-style: none; }
.timeline-items li {
  padding: 0.4rem 0; font-size: 0.85rem; color: var(--text2);
  border-bottom: 1px solid var(--border);
}
.timeline-items li:last-child { border-bottom: none; }
.timeline-items .hn-points { color: var(--orange); font-weight: 600; font-size: 0.8rem; }

/* GitHub Table */
.gh-table { width: 100%; border-collapse: collapse; margin-top: 0.5rem; font-size: 0.85rem; }
.gh-table th {
  text-align: left; padding: 0.5rem; color: var(--text2);
  font-weight: 500; border-bottom: 1px solid var(--border);
}
.gh-table td { padding: 0.5rem; border-bottom: 1px solid var(--border); }
.gh-table .stars { color: var(--orange); font-weight: 600; }

/* About */
.about-content { max-width: 700px; }
.about-content h2 { font-size: 1.3rem; margin: 2rem 0 0.75rem; color: var(--accent); }
.about-content p, .about-content li {
  color: var(--text2); font-size: 0.95rem; line-height: 1.8;
}
.about-content ul { padding-left: 1.5rem; margin: 0.5rem 0; }

/* Footer */
.footer {
  text-align: center; padding: 2rem; color: var(--text2);
  font-size: 0.8rem; border-top: 1px solid var(--border); margin-top: 3rem;
}

/* Loading & Empty */
.loading { text-align: center; padding: 3rem; color: var(--text2); }
.empty { text-align: center; padding: 3rem; color: var(--text2); font-size: 0.9rem; }

/* Toggle */
.toggle-section {
  cursor: pointer; user-select: none;
  display: flex; align-items: center; gap: 0.5rem;
}
.toggle-section .arrow { transition: transform 0.2s; font-size: 0.8rem; color: var(--text2); }
.toggle-section.open .arrow { transform: rotate(90deg); }
.toggle-body { display: none; margin-top: 0.75rem; }
.toggle-body.show { display: block; }

/* Responsive */
@media (max-width: 768px) {
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .nav-links { gap: 1rem; }
  .container { padding: 1rem; }
  .hero h1 { font-size: 1.6rem; }
  .category-grid { grid-template-columns: 1fr; }
}
@media (max-width: 480px) {
  .stats-grid { grid-template-columns: 1fr; }
  .nav-links a { font-size: 0.8rem; }
}