/* Rail Catalogue — reference-style, editorial tech, credible */

:root {
  --font-system: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --accent: #334155;
  --accent-muted: #475569;
  --text: #1e293b;
  --text-muted: #64748b;
  --border: #e2e8f0;
  --bg-subtle: #f8fafc;
  --bg-callout: #f1f5f9;
  --badge-high-bg: #dcfce7;
  --badge-high-fg: #166534;
  --badge-medium-bg: #fef9c3;
  --badge-medium-fg: #854d0e;
  --badge-low-bg: #fee2e2;
  --badge-low-fg: #991b1b;
  --badge-timing-bg: #e0e7ff;
  --badge-timing-fg: #3730a3;
  --radius: 8px;
  --radius-sm: 4px;
}

*, *::before, *::after { box-sizing: border-box; }

body {
  margin: 0;
  background: #fff;
  color: var(--text);
  font-family: var(--font-system);
  font-size: 17px;
  line-height: 1.6;
}

/* Top bar */
.top-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.75rem 1.5rem;
  font-size: 0.8125rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--text-muted);
  border-bottom: 1px solid var(--border);
  background: #fff;
}

/* Main container */
main {
  max-width: 820px;
  margin: 0 auto;
  padding: 3rem 1.5rem 4rem;
}

/* Section rhythm */
.section {
  padding: 3rem 0;
}

.section + .section {
  border-top: 1px solid var(--border);
}

/* Kickers */
.kicker {
  display: block;
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent-muted);
  margin-bottom: 0.35rem;
}

/* Headings */
h1, h2, h3 {
  font-family: var(--font-system);
  font-weight: 600;
  color: var(--text);
}

.section h2 {
  font-size: 1.375rem;
  margin: 0 0 1.25rem;
  letter-spacing: -0.01em;
}

.section p {
  margin: 0 0 1rem;
}

.section p:last-child {
  margin-bottom: 0;
}

/* Hero */
.hero {
  padding: 2.5rem 0 3.5rem;
  border-bottom: 1px solid var(--border);
}

.hero h1 {
  font-size: clamp(2.125rem, 5vw, 3.25rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.2;
  margin: 0 0 0.75rem;
  color: var(--text);
}

.hero .subtitle {
  font-size: 1.25rem;
  color: var(--accent-muted);
  margin: 0 0 1.25rem;
  font-weight: 500;
}

.hero .description {
  font-size: 1.0625rem;
  margin: 0;
  max-width: 42ch;
}

/* Callouts */
.callout {
  padding: 1.25rem 1.5rem;
  margin: 1.25rem 0 1.5rem;
  background: var(--bg-callout);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.callout-determinism .callout-lead {
  font-weight: 600;
  margin: 0 0 0.5rem;
  color: var(--text);
}

.callout-determinism .callout-note {
  font-size: 0.9375rem;
  color: var(--text-muted);
  margin: 0;
}

.callout-insight {
  margin: 1rem 0 1.5rem;
  padding: 1.5rem 1.75rem;
  background: var(--bg-callout);
  border-left: 4px solid var(--accent);
  border-radius: 0 var(--radius) var(--radius) 0;
  border-top: 1px solid var(--border);
  border-right: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.callout-insight .insight-lead {
  font-size: 1.0625rem;
  font-weight: 600;
  margin: 0;
  line-height: 1.5;
}

/* Table */
.table-wrap {
  overflow-x: auto;
  margin: 1.25rem 0 1.5rem;
  -webkit-overflow-scrolling: touch;
}

table {
  width: 100%;
  min-width: 420px;
  border-collapse: collapse;
  font-size: 0.9375rem;
}

th, td {
  text-align: left;
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border);
}

th {
  font-weight: 600;
  background: var(--bg-subtle);
  color: var(--accent-muted);
  font-size: 0.8125rem;
  letter-spacing: 0.03em;
  text-transform: uppercase;
}

tbody tr:nth-child(even) {
  background: var(--bg-subtle);
}

tbody tr:hover {
  background: #f1f5f9;
}

/* Badges / pills */
.badge {
  display: inline-block;
  padding: 0.25rem 0.6rem;
  font-size: 0.8125rem;
  font-weight: 600;
  border-radius: 999px;
  white-space: nowrap;
}

.badge-high {
  background: var(--badge-high-bg);
  color: var(--badge-high-fg);
}

.badge-medium {
  background: var(--badge-medium-bg);
  color: var(--badge-medium-fg);
}

.badge-low {
  background: var(--badge-low-bg);
  color: var(--badge-low-fg);
}

.badge-timing {
  background: var(--badge-timing-bg);
  color: var(--badge-timing-fg);
}

.tradeoffs {
  margin: 0;
  padding-left: 1.25rem;
}

.tradeoffs li {
  margin-bottom: 0.5rem;
}

/* Cards (What this is / is not) */
.two-col.cards {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
  margin-top: 0.75rem;
}

@media (max-width: 600px) {
  .two-col.cards {
    grid-template-columns: 1fr;
  }
}

.card {
  padding: 1.25rem 1.5rem;
  background: var(--bg-subtle);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.card h3 {
  font-size: 0.9375rem;
  font-weight: 600;
  margin: 0 0 0.75rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.card-icon {
  font-size: 1rem;
  opacity: 0.7;
}

.card-is .card-icon { color: var(--badge-high-fg); }
.card-not .card-icon { color: var(--badge-low-fg); }

.card ul {
  margin: 0;
  padding-left: 1.25rem;
}

.card li {
  margin-bottom: 0.4rem;
  font-size: 0.9375rem;
}

/* Footer */
footer {
  padding: 3rem 0 0;
  font-size: 0.875rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border);
  margin-top: 0.5rem;
}

footer p {
  margin: 0 0 0.2rem;
}

.footer-note {
  margin-top: 0.35rem;
  font-style: italic;
}

.footer-meta {
  margin-top: 1.25rem !important;
  font-size: 0.8125rem;
  color: var(--text-muted);
  opacity: 0.9;
}

/* Responsive */
@media (max-width: 640px) {
  main {
    padding: 2rem 1rem 3rem;
  }

  .hero {
    padding: 1.5rem 0 2.5rem;
  }

  .hero h1 {
    font-size: 2.125rem;
  }

  .section {
    padding: 2rem 0;
  }

  .callout,
  .callout-insight {
    padding: 1rem 1.25rem;
  }

  th, td {
    padding: 0.6rem 0.75rem;
  }
}