/* Historical Dating Graph — shared lab chrome */
:root {
  --bg: #0c0f14;
  --bg-elevated: #121826;
  --panel: #161d2b;
  --panel-2: #1a2030;
  --text: #e8e6e3;
  --muted: #9aa3b5;
  --faint: #6b7385;
  --strong: #3dd68c;
  --medium: #e6b84d;
  --weak: #f07178;
  --line: #2a3348;
  --line-strong: #3a455c;
  --accent: #7aa2ff;
  --accent-dim: rgba(122, 162, 255, 0.14);
  --ghost: #3d465c;
  --radius: 10px;
  --radius-sm: 7px;
  --font: "IBM Plex Sans", system-ui, -apple-system, sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, monospace;
  --nav-h: 52px;
  --shadow: 0 8px 28px rgba(0, 0, 0, 0.35);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
  min-height: 100vh;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* —— Top nav —— */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 50;
  height: var(--nav-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0 1.15rem;
  background: rgba(18, 24, 38, 0.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
.site-nav .brand {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  color: var(--text);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.92rem;
  letter-spacing: -0.01em;
}
.site-nav .brand:hover { text-decoration: none; }
.site-nav .brand-mark {
  width: 28px;
  height: 28px;
  border-radius: 8px;
  background: linear-gradient(145deg, #2a3a5c, #1a2030);
  border: 1px solid var(--line-strong);
  display: grid;
  place-items: center;
  font-size: 0.7rem;
  color: var(--accent);
}
.site-nav .brand span.sub {
  font-weight: 400;
  color: var(--muted);
  font-size: 0.78rem;
  margin-left: 0.15rem;
}
.site-nav .nav-links {
  display: flex;
  align-items: center;
  gap: 0.25rem;
}
.site-nav .nav-links a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.84rem;
  padding: 0.4rem 0.75rem;
  border-radius: 999px;
}
.site-nav .nav-links a:hover {
  color: var(--text);
  background: rgba(255, 255, 255, 0.04);
  text-decoration: none;
}
.site-nav .nav-links a.active {
  color: var(--text);
  background: var(--accent-dim);
  color: #c9d8ff;
}

/* —— Shared controls —— */
.swatch {
  display: inline-block;
  width: 10px;
  height: 10px;
  border-radius: 2px;
  margin-right: 4px;
  vertical-align: middle;
}
.badge {
  font-size: 0.65rem;
  padding: 0.18rem 0.45rem;
  border-radius: 999px;
  border: 1px solid var(--line);
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  display: inline-block;
}
.badge.r-weak, .badge.warn { color: var(--weak); border-color: #7a3a40; }
.badge.r-medium { color: var(--medium); border-color: #7a6230; }
.badge.r-strong, .badge.ok { color: var(--strong); border-color: #2a6a4a; }
.badge.accent { color: #c9d8ff; border-color: #3d5280; }

/* —— Methodology page —— */
.method-page {
  max-width: 820px;
  margin: 0 auto;
  padding: 1.75rem 1.25rem 4rem;
}
.method-page .hero {
  margin-bottom: 1.75rem;
  padding-bottom: 1.25rem;
  border-bottom: 1px solid var(--line);
}
.method-page .hero h1 {
  margin: 0 0 0.5rem;
  font-size: 1.65rem;
  letter-spacing: -0.02em;
  font-weight: 650;
}
.method-page .hero .lede {
  margin: 0;
  color: var(--muted);
  font-size: 1.02rem;
  max-width: 58ch;
}
.method-page .toc {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin: 1rem 0 0;
}
.method-page .toc a {
  font-size: 0.78rem;
  padding: 0.35rem 0.7rem;
  border-radius: 999px;
  border: 1px solid var(--line);
  color: var(--muted);
  text-decoration: none;
  background: var(--bg-elevated);
}
.method-page .toc a:hover {
  border-color: var(--line-strong);
  color: var(--text);
  text-decoration: none;
}

.method-page section {
  margin: 2rem 0;
}
.method-page h2 {
  margin: 0 0 0.75rem;
  font-size: 1.2rem;
  letter-spacing: -0.015em;
}
.method-page h3 {
  margin: 1.25rem 0 0.45rem;
  font-size: 0.95rem;
  color: #d5d2cc;
}
.method-page p, .method-page li {
  color: #c8c5bf;
  font-size: 0.95rem;
}
.method-page ul, .method-page ol {
  padding-left: 1.25rem;
}
.method-page li { margin-bottom: 0.35rem; }

.eli5 {
  background: linear-gradient(165deg, rgba(122, 162, 255, 0.1), rgba(18, 24, 38, 0.9));
  border: 1px solid #2e3d5c;
  border-radius: 14px;
  padding: 1.15rem 1.25rem 1.25rem;
  box-shadow: var(--shadow);
}
.eli5 .tag {
  display: inline-block;
  font-size: 0.68rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: #c9d8ff;
  margin-bottom: 0.5rem;
  font-weight: 600;
}
.eli5 h2 { margin-top: 0; color: var(--text); }
.eli5 p { color: #d0d4de; }
.eli5 .analogy {
  margin: 0.9rem 0 0;
  padding: 0.75rem 0.9rem;
  border-left: 3px solid var(--accent);
  background: rgba(0, 0, 0, 0.2);
  border-radius: 0 8px 8px 0;
  color: #d8dce8;
  font-size: 0.92rem;
}

.card-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
}
@media (max-width: 700px) {
  .card-grid { grid-template-columns: 1fr; }
  .site-nav .brand span.sub { display: none; }
}
.card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 0.9rem 1rem;
}
.card h3 { margin: 0 0 0.35rem; font-size: 0.88rem; color: var(--text); }
.card p { margin: 0; font-size: 0.84rem; color: var(--muted); }

table.data {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.84rem;
  margin: 0.75rem 0 1rem;
}
table.data th, table.data td {
  text-align: left;
  padding: 0.5rem 0.55rem;
  border-bottom: 1px solid var(--line);
  vertical-align: top;
}
table.data th {
  color: var(--muted);
  font-weight: 600;
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
table.data td { color: #c8c5bf; }
table.data tr:hover td { background: rgba(255, 255, 255, 0.02); }

.callout {
  border-radius: var(--radius);
  padding: 0.85rem 1rem;
  margin: 1rem 0;
  border: 1px solid var(--line);
  background: var(--bg-elevated);
  font-size: 0.9rem;
}
.callout.strong { border-color: #2a6a4a; background: rgba(61, 214, 140, 0.06); }
.callout.weak { border-color: #7a3a40; background: rgba(240, 113, 120, 0.06); }
.callout.note { border-color: #3d5280; background: var(--accent-dim); }
.callout strong { color: var(--text); }

.steps {
  counter-reset: step;
  list-style: none;
  padding: 0;
  margin: 0.75rem 0;
}
.steps li {
  counter-increment: step;
  position: relative;
  padding: 0.75rem 0.75rem 0.75rem 3rem;
  margin-bottom: 0.5rem;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}
.steps li::before {
  content: counter(step);
  position: absolute;
  left: 0.75rem;
  top: 0.85rem;
  width: 1.5rem;
  height: 1.5rem;
  border-radius: 999px;
  background: var(--accent-dim);
  color: #c9d8ff;
  font-size: 0.75rem;
  font-weight: 700;
  display: grid;
  place-items: center;
}
.steps li strong { color: var(--text); display: block; margin-bottom: 0.15rem; }

.footer-meta {
  margin-top: 3rem;
  padding-top: 1rem;
  border-top: 1px solid var(--line);
  font-size: 0.78rem;
  color: var(--faint);
}
.footer-meta code {
  font-family: var(--mono);
  font-size: 0.74rem;
  color: var(--muted);
}
.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}
@media (max-width: 700px) {
  .two-col { grid-template-columns: 1fr; }
}