:root {
  color-scheme: light;
  --ink: #172b4d;
  --muted: #52606d;
  --line: #d8e0e8;
  --surface: #ffffff;
  --surface-alt: #f5f8fa;
  --accent: #0066cc;
  --accent-dark: #004b95;
  --shadow: 0 10px 32px rgba(23, 43, 77, 0.08);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: #f7f9fb;
  font: 16px/1.6 Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}
a { color: var(--accent-dark); }
a:hover { color: var(--accent); }
.site-header {
  border-bottom: 1px solid #0b4f71;
  color: #fff;
  background: linear-gradient(135deg, #082f49 0%, #0e7490 100%);
}
.header-inner, main, .site-footer-inner { width: min(1180px, calc(100% - 40px)); margin: 0 auto; }
.header-inner { padding: 28px 0 24px; }
.eyebrow { margin: 0 0 4px; color: #bfe8f2; font-size: .78rem; font-weight: 700; letter-spacing: .12em; text-transform: uppercase; }
h1, h2, h3 { line-height: 1.2; }
h1 { margin: 0; font-size: clamp(2rem, 5vw, 3.5rem); letter-spacing: -.04em; }
h2 { margin-top: 0; font-size: 1.55rem; }
h3 { margin-bottom: .35rem; font-size: 1.05rem; }
.lede { max-width: 760px; margin: 14px 0 0; color: #e2f3f7; font-size: 1.08rem; }
.breadcrumb { margin: 0 0 22px; font-size: .9rem; }
.breadcrumb a { color: #d8f3fa; }
main { padding: 42px 0 64px; }
.intro { max-width: 820px; margin-bottom: 30px; }
.meta { color: var(--muted); font-size: .9rem; }
.grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(245px, 1fr)); gap: 18px; }
.card, .diagram-card, .note {
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--surface);
  box-shadow: var(--shadow);
}
.card { display: flex; flex-direction: column; padding: 20px; }
.card p { margin: 0 0 15px; color: var(--muted); font-size: .94rem; }
.card a { margin-top: auto; font-weight: 700; text-decoration: none; }
.diagram-card { margin: 26px 0; padding: clamp(16px, 3vw, 30px); overflow: hidden; }
.diagram-card figure { margin: 0; }
.diagram-card svg { display: block; width: 100%; height: auto; max-height: 780px; }
figcaption { margin-top: 15px; color: var(--muted); font-size: .92rem; }
.note { margin: 24px 0; padding: 16px 20px; background: var(--surface-alt); box-shadow: none; }
.note strong { color: var(--ink); }
details { margin-top: 22px; border-top: 1px solid var(--line); padding-top: 16px; }
summary { cursor: pointer; color: var(--accent-dark); font-weight: 700; }
pre {
  overflow: auto;
  margin: 14px 0 0;
  border-radius: 8px;
  padding: 16px;
  color: #dbeafe;
  background: #102a43;
  font: .78rem/1.55 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  white-space: pre-wrap;
}
.page-nav { display: flex; flex-wrap: wrap; gap: 8px 16px; margin-top: 18px; }
.page-nav a { color: #d8f3fa; font-size: .9rem; }
.site-footer { border-top: 1px solid var(--line); background: #fff; }
.site-footer-inner { padding: 24px 0 36px; color: var(--muted); font-size: .88rem; }
@media (max-width: 650px) {
  .header-inner, main, .site-footer-inner { width: min(100% - 28px, 1180px); }
  main { padding-top: 28px; }
  .diagram-card { padding: 10px; }
}
@media print {
  .site-header { color: #000; background: #fff; border-bottom: 2px solid #000; }
  .lede, .eyebrow, .page-nav a, .breadcrumb a { color: #000; }
  .diagram-card, .card { box-shadow: none; break-inside: avoid; }
  details { display: none; }
}