:root {
  --phase-1: #0066CC;
  --phase-2: #2A9D4E;
  --phase-3: #E67E22;
  --phase-4: #C0392B;
  --bg: #FAFAF8;
  --bg-alt: #F0EFEB;
  --ink: #1A1A18;
  --ink-light: #5C5C58;
  --ink-faint: #9C9C96;
  --accent: #0066CC;
  --rule: #D4D4CE;
  --positive: #2A9D4E;
  --negative: #C0392B;
  --max-w: 960px;
}

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

body {
  font-family: 'IBM Plex Sans', -apple-system, sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.65;
  font-size: 17px;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 24px;
}

/* ── Navigation ── */
.site-nav {
  border-bottom: 1px solid var(--rule);
  padding: 14px 0;
  position: sticky;
  top: 0;
  background: var(--bg);
  z-index: 100;
}
.site-nav .container {
  display: flex;
  gap: 28px;
  align-items: center;
}
.site-nav a {
  color: var(--ink-faint);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0.01em;
  transition: color 0.15s;
}
.site-nav a:hover { color: var(--ink); }
.site-nav a.nav-active { color: var(--ink); font-weight: 600; }

/* ── Hero ── */
.hero {
  padding: 80px 0 40px;
  border-bottom: 3px solid var(--ink);
}
.hero-eyebrow {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin-bottom: 16px;
}
.hero h1 {
  font-family: 'DM Serif Display', serif;
  font-size: clamp(36px, 6vw, 64px);
  line-height: 1.08;
  letter-spacing: -0.02em;
  margin-bottom: 20px;
  max-width: 14em;
}
.hero-subtitle {
  font-size: 20px;
  line-height: 1.5;
  color: var(--ink-light);
  max-width: 38em;
}

/* ── Smaller hero for subpages ── */
.hero-sm {
  padding: 48px 0 32px;
  border-bottom: 3px solid var(--ink);
}
.hero-sm .hero-eyebrow {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin-bottom: 12px;
}
.hero-sm h1 {
  font-family: 'DM Serif Display', serif;
  font-size: clamp(28px, 5vw, 48px);
  line-height: 1.12;
  letter-spacing: -0.02em;
  margin-bottom: 16px;
  max-width: 16em;
}
.hero-sm .hero-subtitle {
  font-size: 18px;
  line-height: 1.5;
  color: var(--ink-light);
  max-width: 38em;
}

/* ── Sections ── */
section {
  padding: 64px 0;
  border-bottom: 1px solid var(--rule);
}
section:last-of-type { border-bottom: none; }

h2 {
  font-family: 'DM Serif Display', serif;
  font-size: 32px;
  letter-spacing: -0.01em;
  margin-bottom: 8px;
}
h3 {
  font-family: 'IBM Plex Sans', sans-serif;
  font-size: 20px;
  font-weight: 600;
  margin-bottom: 8px;
  margin-top: 32px;
}
.section-lead {
  color: var(--ink-light);
  font-size: 18px;
  line-height: 1.55;
  margin-bottom: 32px;
  max-width: 38em;
}

/* ── Prose (for methodology/headway pages) ── */
.prose p {
  margin-bottom: 16px;
  max-width: 38em;
  line-height: 1.7;
}
.prose ul, .prose ol {
  margin-bottom: 16px;
  padding-left: 24px;
  max-width: 38em;
}
.prose li {
  margin-bottom: 8px;
  line-height: 1.6;
}
.prose code {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.9em;
  background: var(--bg-alt);
  padding: 2px 6px;
  border-radius: 3px;
}
.prose strong { font-weight: 600; }
.prose a {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}

/* ── Key Finding Callout ── */
.callout {
  background: var(--ink);
  color: #fff;
  padding: 48px;
  margin: 0 -24px;
  position: relative;
}
.callout::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--phase-1) 25%, var(--phase-2) 25%, var(--phase-2) 50%, var(--phase-3) 50%, var(--phase-3) 75%, var(--phase-4) 75%);
}
.callout-label {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.5);
  margin-bottom: 16px;
}
.callout h2 {
  color: #fff;
  font-size: clamp(28px, 4vw, 44px);
  line-height: 1.15;
  margin-bottom: 24px;
}
.callout p { color: rgba(255,255,255,0.75); max-width: 38em; }

/* ── Warning/preliminary data callout ── */
.callout-warning {
  background: #FFF8E1;
  border: 1px solid #FFE082;
  border-left: 4px solid var(--phase-3);
  padding: 24px 28px;
  border-radius: 4px;
  margin-bottom: 32px;
}
.callout-warning p {
  color: var(--ink);
  margin: 0;
  font-size: 15px;
  line-height: 1.6;
}
.callout-warning strong { font-weight: 600; }

/* ── Phase pills ── */
.phase-legend {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  margin: 16px 0 24px;
}
.phase-pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  font-weight: 600;
  color: var(--ink-light);
}
.phase-dot {
  width: 12px; height: 12px;
  border-radius: 50%;
  display: inline-block;
}

/* ── Map ── */
#map {
  height: 520px;
  border-radius: 4px;
  border: 1px solid var(--rule);
  z-index: 1;
}
.leaflet-popup-content-wrapper {
  font-family: 'IBM Plex Sans', sans-serif;
  font-size: 14px;
  border-radius: 4px;
  box-shadow: 0 4px 20px rgba(0,0,0,0.15);
}
.popup-route { font-weight: 700; font-size: 16px; margin-bottom: 4px; }
.popup-phase { color: var(--ink-faint); font-size: 12px; }
.popup-stat { margin-top: 8px; font-family: 'IBM Plex Mono', monospace; font-size: 13px; }
.popup-stat .positive { color: var(--positive); font-weight: 600; }
.popup-stat .negative { color: var(--negative); font-weight: 600; }

/* ── Chart containers ── */
.chart-wrap {
  margin: 0 -24px;
  background: #fff;
  border: 1px solid var(--rule);
  border-radius: 4px;
  overflow: hidden;
}
.chart-wrap .js-plotly-plot { width: 100% !important; }

/* ── DiD results table ── */
.did-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 15px;
  margin-bottom: 32px;
}
.did-table th {
  text-align: left;
  font-weight: 600;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--ink-faint);
  padding: 12px 16px;
  border-bottom: 2px solid var(--ink);
}
.did-table td {
  padding: 14px 16px;
  border-bottom: 1px solid var(--rule);
  vertical-align: middle;
}
.did-table tr:last-child td { border-bottom: none; }
.did-phase-dot {
  display: inline-block;
  width: 10px; height: 10px;
  border-radius: 50%;
  margin-right: 8px;
}
.did-estimate {
  font-family: 'IBM Plex Mono', monospace;
  font-weight: 500;
  font-size: 15px;
}
.did-ci {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 13px;
  color: var(--ink-faint);
}

/* ── Notebook overview table ── */
.nb-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
  margin: 24px 0 32px;
}
.nb-table th {
  text-align: left;
  font-weight: 600;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--ink-faint);
  padding: 10px 12px;
  border-bottom: 2px solid var(--ink);
}
.nb-table td {
  padding: 12px 12px;
  border-bottom: 1px solid var(--rule);
  vertical-align: top;
  line-height: 1.5;
}
.nb-table tr:last-child td { border-bottom: none; }
.nb-num {
  font-family: 'IBM Plex Mono', monospace;
  font-weight: 500;
  color: var(--ink-faint);
  font-size: 13px;
}

/* ── Methodology accordion ── */
details {
  border: 1px solid var(--rule);
  border-radius: 4px;
  margin-bottom: 12px;
}
details summary {
  padding: 16px 20px;
  cursor: pointer;
  font-weight: 600;
  font-size: 15px;
  list-style: none;
  display: flex;
  align-items: center;
  gap: 10px;
  user-select: none;
}
details summary::before {
  content: '+';
  font-family: 'IBM Plex Mono', monospace;
  font-size: 18px;
  color: var(--ink-faint);
  width: 20px;
  text-align: center;
  flex-shrink: 0;
}
details[open] summary::before { content: '\2212'; }
details summary::-webkit-details-marker { display: none; }
.method-content {
  padding: 0 20px 20px 50px;
  color: var(--ink-light);
  font-size: 15px;
  line-height: 1.7;
}
.method-content p { margin-bottom: 12px; }

/* ── Page link arrow ── */
.page-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--accent);
  text-decoration: none;
  font-weight: 600;
  font-size: 16px;
  margin-top: 16px;
}
.page-link:hover { text-decoration: underline; }

/* ── Footer ── */
footer {
  padding: 48px 0;
  border-top: 2px solid var(--ink);
  color: var(--ink-faint);
  font-size: 14px;
}
footer a { color: var(--ink-light); }
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: 40px;
}
.footer-sources dt {
  font-weight: 600;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--ink-light);
  margin-top: 12px;
}
.footer-sources dd { margin-left: 0; }

@media (max-width: 640px) {
  .container { padding: 0 16px; }
  .hero { padding: 48px 0 32px; }
  .hero-sm { padding: 32px 0 24px; }
  section { padding: 40px 0; }
  .callout { padding: 32px 16px; margin: 0 -16px; }
  #map { height: 360px; }
  .chart-wrap { margin: 0 -16px; }
  .footer-grid { grid-template-columns: 1fr; }
  .did-table { font-size: 13px; }
  .did-table th, .did-table td { padding: 10px 8px; }
  .nb-table { font-size: 13px; }
  .nb-table th, .nb-table td { padding: 8px 6px; }
}