:root {
  --bg: #FAFAF8;
  --surface: #ffffff;
  --border: #E4E2DC;
  --text: #1C1B18;
  --muted: #6B6860;
  --accent: #99ADD6;
  --accent-soft: #E1E8F5;
  --navy: #003399;
  --chart-1: #003399;
  --chart-2: #99ADD6;
  --chart-3: #4A6AAF;
  --chart-4: #2a8c82;
  --chart-5: #7a4fc4;
  --chart-6: #d76d3f;
  --chart-7: #4a90d9;
}

* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: "Open Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
}
a { color: var(--navy); }
a:hover { color: var(--accent); }

.wrap { max-width: 1280px; margin: 0 auto; padding: 0 24px; }

.site-header {
  background:
    linear-gradient(135deg, rgba(0,28,85,0.86), rgba(0,51,153,0.80)),
    url("../hero-bg.jpg") center / cover no-repeat,
    #003399;
  color: #fff;
  padding: 28px 0 0;
  border-bottom: 3px solid var(--accent);
}
.site-header h1 { margin: 0; font-size: 28px; font-weight: 700; letter-spacing: -0.3px; }
.site-header .subtitle { margin: 6px 0 18px; color: #cfd7e2; font-size: 14px; }
.site-header a { color: #8BD4E0; }

.tabs { display: flex; flex-wrap: wrap; gap: 4px; margin-top: 12px; }
.tab {
  background: transparent;
  border: none;
  padding: 12px 20px;
  color: #cfd7e2;
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  border-bottom: 3px solid transparent;
  transition: all 0.15s;
}
.tab:hover { color: #fff; }
.tab.active { color: #fff; border-bottom-color: var(--accent); }

main.wrap { padding-top: 28px; padding-bottom: 48px; }

.tab-panel { display: none; }
.tab-panel.active { display: block; }

/* Stats */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
  gap: 16px;
  margin-bottom: 24px;
}
.stat-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 20px;
  text-align: center;
}
.stat-num {
  font-size: 32px;
  font-weight: 700;
  color: var(--navy);
  line-height: 1.1;
  min-height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
}
.stat-label { font-size: 13px; color: var(--muted); margin-top: 6px; text-transform: uppercase; letter-spacing: 0.5px; }

/* Charts */
.chart-row { margin-bottom: 20px; }
.chart-row.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.chart-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 18px 20px;
}
.chart-card h2 { margin: 0 0 12px; font-size: 16px; font-weight: 600; color: var(--navy); }
.chart-card h2 .chart-subtitle { font-weight: 400; color: var(--muted); font-size: 13px; margin-left: 6px; }
.chart-card canvas { max-height: 320px; }
.chart-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 12px; }
.chart-header h2 { margin: 0; }

.seg { display: inline-flex; border: 1px solid var(--border); border-radius: 6px; overflow: hidden; }
.seg button {
  border: none;
  background: #fff;
  padding: 6px 12px;
  font-size: 13px;
  cursor: pointer;
  color: var(--muted);
}
.seg button.active { background: var(--navy); color: #fff; }

/* Controls */
.controls {
  display: flex;
  gap: 12px;
  align-items: center;
  margin-bottom: 16px;
  flex-wrap: wrap;
}
.controls input[type=search],
.controls select {
  border: 1px solid var(--border);
  background: #fff;
  border-radius: 6px;
  padding: 9px 12px;
  font-size: 14px;
  font-family: inherit;
  color: var(--text);
}
.controls input[type=search] { flex: 1; min-width: 240px; }
.controls select { min-width: 180px; }
.result-count { color: var(--muted); font-size: 13px; margin-left: auto; }
.active-filter-pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 6px 4px 10px;
  background: var(--accent-soft);
  color: var(--navy);
  border: 1px solid #c7e3eb;
  border-radius: 16px;
  font-size: 13px;
}
.active-filter-pill strong { font-weight: 600; }
.active-filter-pill .clear-filter {
  background: transparent;
  border: none;
  color: var(--navy);
  cursor: pointer;
  font-size: 16px;
  line-height: 1;
  padding: 0 4px;
  font-family: inherit;
}
.active-filter-pill .clear-filter:hover { color: var(--accent); }

/* Papers table */
.table-scroll {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  overflow: auto;
}
.papers-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
}
.papers-table th, .papers-table td {
  padding: 12px 14px;
  text-align: left;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}
.papers-table th {
  background: #fafbfd;
  font-weight: 600;
  color: var(--navy);
  font-size: 13px;
  position: sticky;
  top: 0;
  z-index: 1;
}
.papers-table th.sortable { cursor: pointer; user-select: none; }
.papers-table th.sortable:hover { color: var(--accent); }
.papers-table th .arrow { display: inline-block; margin-left: 4px; opacity: 0.4; }
.papers-table th.sort-asc .arrow::before { content: "▲"; opacity: 1; }
.papers-table th.sort-desc .arrow::before { content: "▼"; opacity: 1; }
.papers-table tbody tr:hover { background: #fafbfd; }
.papers-table td.date { white-space: nowrap; color: var(--muted); font-variant-numeric: tabular-nums; }
.papers-table td.title a { text-decoration: none; font-weight: 500; }
.papers-table td.title a:hover { text-decoration: underline; }

/* Direction pill */
.pill {
  display: inline-block;
  padding: 2px 10px;
  border-radius: 20px;
  font-size: 12px;
  font-weight: 500;
  white-space: nowrap;
  cursor: pointer;
  transition: filter 0.15s;
}
.pill[data-direction]:hover { filter: brightness(0.95); }

.inst-list { color: var(--muted); font-size: 13px; }
.author-list { font-size: 13px; }
.chip {
  display: inline-block;
  padding: 1px 8px;
  margin: 1px 2px 1px 0;
  background: #f0f2f7;
  border-radius: 4px;
  font-size: 12px;
  color: var(--text);
  cursor: pointer;
}
.chip:hover { background: var(--accent-soft); color: var(--accent); }

/* Pagination */
.pagination {
  display: flex;
  justify-content: center;
  gap: 4px;
  margin-top: 16px;
  flex-wrap: wrap;
}
.pagination button {
  border: 1px solid var(--border);
  background: #fff;
  padding: 6px 12px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 13px;
  color: var(--text);
}
.pagination button:hover { border-color: var(--navy); }
.pagination button.active { background: var(--navy); color: #fff; border-color: var(--navy); }
.pagination button:disabled { opacity: 0.4; cursor: not-allowed; }

/* Tab intro paragraph */
.tab-intro {
  margin: 0 0 18px;
  padding: 14px 18px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: 8px;
  color: var(--text);
  font-size: 14px;
  line-height: 1.55;
}

/* Labs */
.labs-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 16px;
}
.lab-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 18px 20px;
}
.lab-card h3 { margin: 0 0 4px; color: var(--navy); font-size: 17px; }
.lab-meta { font-size: 13px; color: var(--muted); margin-bottom: 12px; }
.lab-meta .type-badge {
  display: inline-block;
  padding: 2px 8px;
  background: #f0f2f7;
  border-radius: 4px;
  margin-right: 6px;
  color: var(--text);
}
.lab-section { margin-top: 12px; }
.lab-section h4 {
  margin: 0 0 6px;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--muted);
  font-weight: 600;
}
.lab-section h4 .paper-count { text-transform: none; color: var(--muted); font-weight: 500; letter-spacing: 0; }
.lab-section ul { margin: 0; padding-left: 18px; font-size: 13px; }
.lab-section li { margin-bottom: 4px; }
.papers-list .hidden-paper { display: none; }
.papers-list.expanded .hidden-paper { display: list-item; }
.papers-toggle-header {
  display: flex;
  align-items: center;
  gap: 6px;
  width: 100%;
  margin: 0 0 6px;
  padding: 2px 0;
  background: transparent;
  border: none;
  font-family: inherit;
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--muted);
  cursor: pointer;
  text-align: left;
}
.papers-toggle-header:hover { color: var(--accent); }
.papers-toggle-header .paper-count {
  text-transform: none;
  font-weight: 500;
  letter-spacing: 0;
  color: var(--muted);
}
.papers-toggle-header .chevron {
  display: inline-block;
  transition: transform 0.15s;
  font-size: 11px;
  color: var(--accent);
}
.papers-toggle-header[aria-expanded="true"] .chevron { transform: rotate(90deg); }

/* About / Methodology */
.prose {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 28px 36px;
  max-width: 860px;
  margin: 0 auto;
}
.prose h2 { color: var(--navy); margin-top: 28px; }
.prose h2:first-child { margin-top: 0; }
.prose p { margin: 12px 0; }

.methodology ol { padding-left: 28px; margin: 12px 0; list-style-type: decimal; }
.methodology ol ol { margin: 10px 0 10px; list-style-type: lower-alpha; }
.methodology ol ol ol { list-style-type: lower-roman; }
.methodology li { margin: 10px 0; line-height: 1.6; }
.methodology li > strong { color: var(--navy); }
.methodology em { font-style: italic; }

.site-footer {
  border-top: 1px solid var(--border);
  background: #fff;
  padding: 20px 0;
  margin-top: 40px;
  font-size: 13px;
  color: var(--muted);
}

@media (max-width: 780px) {
  .chart-row.two-col { grid-template-columns: 1fr; }
  .site-header h1 { font-size: 22px; }
  .papers-table { font-size: 13px; }
  .papers-table th, .papers-table td { padding: 8px 10px; }
  .tab { padding: 10px 14px; font-size: 13px; }
}