:root {
  color-scheme: light;
  --ink: #142127;
  --muted: #49606a;
  --surface: #ffffff;
  --canvas: #f4f8f9;
  --line: #d6e2e5;
  --brand: #176f91;
  --brand-dark: #105771;
  --brand-soft: #e0f1f7;
  --warning: #6e4d10;
  --warning-bg: #fff8e8;
  --max: 1120px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; color: var(--ink); background: var(--canvas); font: 16px/1.6 Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; }
a { color: var(--brand-dark); }
a:hover { color: var(--brand); }
:focus-visible { outline: 3px solid #e49a16; outline-offset: 3px; }
.skip-link { position: absolute; left: 1rem; top: -4rem; z-index: 10; padding: .65rem .9rem; color: #fff; background: var(--brand-dark); }
.skip-link:focus { top: 1rem; }
.shell { width: min(var(--max), calc(100% - 2rem)); margin: 0 auto; }
.site-header { padding: 1rem 0; background: rgba(255,255,255,.92); border-bottom: 1px solid var(--line); }
.site-header .shell, .site-footer .shell { display: flex; gap: 1rem; align-items: center; justify-content: space-between; flex-wrap: wrap; }
.brand { font-weight: 800; color: var(--ink); text-decoration: none; letter-spacing: -.02em; }
.brand span { color: var(--brand); }
nav ul, .footer-links { display: flex; gap: 1rem; flex-wrap: wrap; margin: 0; padding: 0; list-style: none; }
nav a { font-weight: 650; text-decoration: none; }
main { padding: 3.5rem 0 4.5rem; }
.hero { display: grid; gap: 2rem; grid-template-columns: 1.25fr .75fr; align-items: center; }
.eyebrow { margin: 0 0 .65rem; color: var(--brand-dark); font-size: .82rem; font-weight: 800; letter-spacing: .08em; text-transform: uppercase; }
h1, h2, h3 { line-height: 1.17; color: var(--ink); }
h1 { margin: 0; max-width: 16ch; font-size: clamp(2.35rem, 6vw, 4.7rem); letter-spacing: -.055em; }
h2 { margin: 0 0 .75rem; font-size: clamp(1.6rem, 3vw, 2.4rem); letter-spacing: -.035em; }
h3 { margin: 0 0 .45rem; font-size: 1.1rem; }
.lead { max-width: 62ch; margin: 1.25rem 0; color: var(--muted); font-size: 1.15rem; }
.actions { display: flex; gap: .8rem; flex-wrap: wrap; margin-top: 1.5rem; }
.button { display: inline-flex; align-items: center; justify-content: center; min-height: 2.85rem; padding: .65rem 1rem; border: 1px solid var(--brand); border-radius: .55rem; font-weight: 750; text-decoration: none; }
.button.primary { color: #fff; background: var(--brand); }
.button.primary:hover { color: #fff; background: var(--brand-dark); }
.button.secondary { background: #fff; }
.hero-card, .card, .notice { border: 1px solid var(--line); border-radius: 1rem; background: var(--surface); }
.hero-card { padding: 1.5rem; box-shadow: 0 14px 35px rgba(20, 33, 39, .08); }
.hero-card p:last-child, .card p:last-child { margin-bottom: 0; }
.metric { display: grid; grid-template-columns: auto 1fr; gap: .75rem; padding: .9rem 0; border-bottom: 1px solid var(--line); }
.metric:last-child { border: 0; padding-bottom: 0; }
.metric strong { color: var(--brand-dark); font-size: 1.25rem; }
.section { margin-top: 4.5rem; }
.section > p { max-width: 68ch; color: var(--muted); }
.grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1rem; margin-top: 1.4rem; }
.grid.two { grid-template-columns: repeat(2, 1fr); }
.card { padding: 1.3rem; }
.card p, .card li { color: var(--muted); }
.card ul { padding-left: 1.2rem; }
.notice { padding: 1.25rem; color: #473513; background: var(--warning-bg); border-color: #ebcf91; }
.notice h2 { font-size: 1.25rem; }
.prose { max-width: 780px; }
.prose section { margin-bottom: 2.6rem; }
.prose p, .prose li { color: var(--muted); }
.prose li + li { margin-top: .4rem; }
.formula { padding: 1rem; overflow-x: auto; border-left: 4px solid var(--brand); background: var(--brand-soft); font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; }
.example { border-left: 4px solid var(--brand); }
.site-footer { padding: 2rem 0; color: var(--muted); background: #e9f0f2; border-top: 1px solid var(--line); font-size: .93rem; }
.site-footer p { margin: 0; }
@media (max-width: 760px) {
  .hero, .grid, .grid.two { grid-template-columns: 1fr; }
  main { padding-top: 2.5rem; }
  h1 { max-width: 18ch; }
}