:root {
  --ink: #17211e;
  --muted: #5f706a;
  --line: #d8e3df;
  --paper: #ffffff;
  --wash: #f4f8f6;
  --brand: #176f5b;
  --brand-dark: #0e5444;
  --accent: #e8f4ef;
  --warning: #fff8e7;
  --shadow: 0 14px 38px rgba(22, 72, 59, 0.08);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  color: var(--ink);
  background: var(--wash);
  font: 16px/1.72 Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

a { color: var(--brand-dark); }
a:hover { color: var(--brand); }

.skip-link {
  position: absolute;
  left: -9999px;
  top: 8px;
  z-index: 20;
  padding: 10px 14px;
  border-radius: 8px;
  background: var(--ink);
  color: #fff;
}

.skip-link:focus { left: 12px; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  border-bottom: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.96);
  backdrop-filter: blur(12px);
}

.header-inner,
.page-shell,
.footer-inner {
  width: min(1080px, calc(100% - 32px));
  margin-inline: auto;
}

.header-inner {
  min-height: 68px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.brand {
  color: var(--ink);
  font-size: 1.08rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  text-decoration: none;
}

.site-nav { display: flex; flex-wrap: wrap; gap: 16px; }
.site-nav a { font-weight: 650; text-decoration: none; }

.page-shell { padding: 28px 0 64px; }

.breadcrumbs {
  margin: 0 0 22px;
  color: var(--muted);
  font-size: 0.92rem;
}

.breadcrumbs a { text-decoration: none; }
.breadcrumbs span { margin: 0 7px; color: #91a19c; }

.hero,
.article {
  border: 1px solid var(--line);
  border-radius: 24px;
  background: var(--paper);
  box-shadow: var(--shadow);
}

.hero { padding: clamp(28px, 5vw, 58px); }
.article { padding: clamp(24px, 5vw, 58px); }

.eyebrow {
  display: inline-flex;
  margin-bottom: 12px;
  padding: 6px 11px;
  border-radius: 999px;
  background: var(--accent);
  color: var(--brand-dark);
  font-size: 0.8rem;
  font-weight: 800;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

h1,
h2,
h3 { line-height: 1.22; letter-spacing: -0.025em; }

h1 {
  max-width: 850px;
  margin: 0 0 18px;
  font-size: clamp(2.15rem, 6vw, 4rem);
}

h2 { margin: 44px 0 12px; font-size: clamp(1.5rem, 3vw, 2rem); }
h3 { margin: 28px 0 8px; font-size: 1.2rem; }

.lead {
  max-width: 780px;
  margin: 0;
  color: var(--muted);
  font-size: 1.13rem;
}

.page-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  margin: 24px 0 0;
  color: var(--muted);
  font-size: 0.9rem;
}

.guide-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
  margin-top: 26px;
}

.guide-card {
  display: flex;
  min-height: 245px;
  flex-direction: column;
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: #fff;
  color: var(--ink);
  text-decoration: none;
  box-shadow: 0 8px 24px rgba(22, 72, 59, 0.05);
}

.guide-card:hover { transform: translateY(-2px); box-shadow: var(--shadow); }
.guide-card h2 { margin: 8px 0 10px; font-size: 1.45rem; }
.guide-card p { margin: 0; color: var(--muted); }
.guide-card .read-more { margin-top: auto; padding-top: 18px; color: var(--brand-dark); font-weight: 800; }
.card-kicker { color: var(--brand); font-size: 0.78rem; font-weight: 800; letter-spacing: 0.05em; text-transform: uppercase; }

.article > :first-child { margin-top: 0; }
.article p,
.article li { max-width: 820px; }
.article ul,
.article ol { padding-left: 23px; }
.article li + li { margin-top: 7px; }

.toc,
.callout,
.formula,
.source-note {
  margin: 26px 0;
  padding: 20px 22px;
  border-radius: 16px;
}

.toc { border: 1px solid var(--line); background: var(--wash); }
.toc strong { display: block; margin-bottom: 7px; }
.toc ol { margin: 0; columns: 2; }
.toc li { break-inside: avoid; margin: 3px 0; }

.callout { border-left: 5px solid var(--brand); background: var(--accent); }
.callout.warning { border-left-color: #c88900; background: var(--warning); }
.callout p { margin: 0; }

.formula {
  overflow-x: auto;
  border: 1px solid #c9ddd6;
  background: #f7fbf9;
  font: 650 1rem/1.65 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

.table-wrap { margin: 22px 0; overflow-x: auto; }

table {
  width: 100%;
  border-collapse: collapse;
  border: 1px solid var(--line);
  background: #fff;
}

th,
td { padding: 13px 15px; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
th { background: #edf5f1; font-size: 0.92rem; }
tr:last-child td { border-bottom: 0; }

.cta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  margin: 38px 0 10px;
  padding: 24px;
  border-radius: 18px;
  background: var(--ink);
  color: #fff;
}

.cta h2 { margin: 0 0 5px; font-size: 1.35rem; }
.cta p { margin: 0; color: #d9e7e2; }
.button {
  flex: 0 0 auto;
  display: inline-block;
  padding: 11px 16px;
  border-radius: 11px;
  background: #fff;
  color: var(--brand-dark);
  font-weight: 800;
  text-decoration: none;
}

.sources { margin-top: 44px; padding-top: 24px; border-top: 1px solid var(--line); }
.sources h2 { margin-top: 0; }
.sources li { overflow-wrap: anywhere; }
.source-note { border: 1px solid var(--line); background: var(--wash); color: var(--muted); font-size: 0.92rem; }

.site-footer { border-top: 1px solid var(--line); background: #eaf2ef; }
.footer-inner { padding: 25px 0; color: var(--muted); font-size: 0.92rem; }
.footer-inner a { margin-right: 12px; }

@media (max-width: 800px) {
  .guide-grid { grid-template-columns: 1fr; }
  .guide-card { min-height: auto; }
  .toc ol { columns: 1; }
}

@media (max-width: 620px) {
  .header-inner { align-items: flex-start; flex-direction: column; padding: 14px 0; }
  .site-nav { gap: 12px; font-size: 0.92rem; }
  .page-shell { padding-top: 20px; }
  .cta { align-items: flex-start; flex-direction: column; }
}