:root {
  --bg: #f5f7f9;
  --surface: #ffffff;
  --ink: #1c2633;
  --muted: #5b6b7b;
  --line: #e2e8ee;
  --accent: #0f766e;
  --accent-ink: #0b5c56;
  --code-bg: #eaf3f0;
  --code-ink: #0b6e5f;
  --term-bg: #0d1b2a;
  --term-fg: #9be7cf;
  --danger: #b3423a;
  --mono: ui-monospace, "SFMono-Regular", "JetBrains Mono", Menlo, Consolas, monospace;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.65;
  color: var(--ink);
  background: var(--bg);
}

.wrap { max-width: 1040px; margin: 0 auto; padding: 0 24px; }

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

/* ---- header ---- */
.site-head {
  background: var(--term-bg);
  border-bottom: 3px solid var(--accent);
}
.site-head .wrap {
  display: flex; align-items: center; justify-content: space-between;
  flex-wrap: wrap; gap: 12px; padding-top: 14px; padding-bottom: 14px;
}
.brand { display: flex; align-items: center; gap: 10px; color: #e8f1ee; }
.brand:hover { text-decoration: none; }
.brand-mark { width: 30px; height: 30px; color: var(--term-fg); }
.brand-name { font-family: var(--mono); font-size: 20px; font-weight: 700; letter-spacing: .5px; }
.brand-sub { font-family: var(--mono); font-size: 12px; color: #8aa3a5; }
.nav { display: flex; gap: 20px; }
.nav a { color: #c4d5d3; font-size: 15px; }
.nav a:hover { color: #ffffff; }

/* ---- hero ---- */
.hero { background: #0d1b2a; color: #e8f1ee; }
.hero .wrap { padding-top: 52px; padding-bottom: 52px; }
.hero-kicker {
  font-family: var(--mono); font-size: 13px; letter-spacing: 2px;
  text-transform: uppercase; color: var(--term-fg); margin: 0 0 12px;
}
.hero h1 { font-family: var(--mono); font-size: clamp(26px, 5vw, 42px); line-height: 1.15; margin: 0 0 16px; }
.hero-lede { font-size: 18px; color: #b9cbca; max-width: 680px; margin: 0 0 26px; }
.hero-actions { display: flex; gap: 12px; flex-wrap: wrap; }
.btn {
  display: inline-block; padding: 10px 18px; border-radius: 6px;
  font-weight: 600; font-size: 15px; color: #fff; background: var(--accent);
}
.btn:hover { text-decoration: none; background: #0e8579; }
.btn-ghost { background: transparent; color: #cfe0dd; border: 1px solid #35505a; }
.btn-ghost:hover { border-color: var(--term-fg); color: #fff; }

/* ---- A-Z nav ---- */
.az { background: var(--surface); border-bottom: 1px solid var(--line); }
.az .wrap { display: flex; flex-wrap: wrap; gap: 4px; padding-top: 10px; padding-bottom: 10px; }
.az a {
  font-family: var(--mono); font-size: 14px; width: 28px; height: 28px;
  display: inline-flex; align-items: center; justify-content: center;
  border-radius: 4px; color: var(--accent-ink); background: #eef5f3;
}
.az a:hover { text-decoration: none; background: #d8ece6; }
.az a.off { color: #b9c3cb; background: #f2f4f6; pointer-events: none; }

/* ---- sections / page head ---- */
main { padding-bottom: 48px; }
.page-head { background: var(--surface); border-bottom: 1px solid var(--line); }
.page-head .wrap { padding-top: 40px; padding-bottom: 28px; }
.page-head h1 { font-family: var(--mono); font-size: 32px; margin: 0 0 8px; }
.lede { color: var(--muted); font-size: 18px; max-width: 720px; margin: 0; }

.page-body .wrap { padding-top: 32px; }
.prose { max-width: 720px; }
.prose h2 { font-size: 22px; margin: 28px 0 10px; }
.prose p { margin: 0 0 16px; }
.prose a { text-decoration: underline; }
.prose code, .term-section code {
  font-family: var(--mono); font-size: .86em;
  background: var(--code-bg); color: var(--code-ink);
  padding: 1px 5px; border-radius: 4px; border: 1px solid #d3e6e0;
}

/* ---- group index (home) ---- */
.group-index { padding: 40px 0; }
.group-index h2, .latest h2 { font-family: var(--mono); font-size: 20px; margin: 0 0 18px; }
.group-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 14px; }
.group-tile {
  display: flex; flex-direction: column; gap: 6px; padding: 18px;
  background: var(--surface); border: 1px solid var(--line); border-radius: 8px;
}
.group-tile:hover { text-decoration: none; border-color: var(--accent); }
.group-name { font-weight: 700; color: var(--ink); font-size: 17px; }
.group-count { font-family: var(--mono); font-size: 13px; color: var(--muted); }

/* ---- toc list ---- */
.latest { padding: 0 0 40px; }
.toc-list { list-style: none; margin: 0; padding: 0; }
.toc-list li {
  display: flex; justify-content: space-between; gap: 16px; align-items: baseline;
  padding: 11px 2px; border-bottom: 1px solid var(--line);
}
.toc-list a { font-weight: 600; }
.toc-group { font-family: var(--mono); font-size: 12px; color: var(--muted); white-space: nowrap; }

/* ---- letter blocks (glossary index) ---- */
.letter-block { background: var(--surface); border-bottom: 1px solid var(--line); }
.letter-block .wrap { padding-top: 26px; padding-bottom: 22px; }
.letter-head {
  font-family: var(--mono); font-size: 24px; color: var(--accent);
  border-bottom: 2px solid var(--accent); display: inline-block; padding-bottom: 4px; margin: 0 0 10px;
}

/* ---- breadcrumbs ---- */
.crumbs { background: var(--surface); border-bottom: 1px solid var(--line); }
.crumbs .wrap { padding-top: 12px; padding-bottom: 12px; font-size: 14px; color: var(--muted); }
.crumbs .sep { color: #b6c0c8; margin: 0 6px; }

/* ---- term article ---- */
.term-head { background: var(--term-bg); color: #e8f1ee; }
.term-head .wrap { padding-top: 40px; padding-bottom: 32px; }
.term-cat {
  font-family: var(--mono); font-size: 13px; letter-spacing: 1px; text-transform: uppercase;
  color: var(--term-fg); margin: 0 0 10px;
}
.term-head h1 { font-family: var(--mono); font-size: clamp(26px, 4.5vw, 38px); line-height: 1.2; margin: 0 0 10px; }
.term-meta { font-size: 14px; color: #8aa3a5; margin: 0 0 14px; }
.term-lede { font-size: 18px; color: #c4d5d3; max-width: 700px; margin: 0; }

.term > .wrap { display: grid; grid-template-columns: 300px 1fr; gap: 34px; align-items: start; padding-top: 34px; }

.term-card { background: var(--surface); border: 1px solid var(--line); border-radius: 8px; overflow: hidden; }
.card-title {
  font-family: var(--mono); font-size: 13px; letter-spacing: 1px; text-transform: uppercase;
  background: var(--term-bg); color: var(--term-fg); margin: 0; padding: 10px 16px;
}
.card { margin: 0; padding: 8px 0; }
.fact { padding: 10px 16px; border-bottom: 1px solid var(--line); }
.fact:last-child { border-bottom: 0; }
.fact dt { font-family: var(--mono); font-size: 12px; text-transform: uppercase; letter-spacing: .5px; color: var(--muted); margin-bottom: 3px; }
.fact dd { margin: 0; font-size: 15px; }
.fact-wide dd ul { list-style: none; margin: 0; padding: 0; }
.fact-wide dd li { padding: 3px 0; }

.term-body { min-width: 0; }
.term-section { margin-bottom: 26px; }
.term-section h2 {
  font-family: var(--mono); font-size: 21px; padding-bottom: 6px;
  border-bottom: 1px solid var(--line); margin: 0 0 14px;
}
.term-section p { margin: 0 0 14px; }

/* ---- footer ---- */
.site-foot { background: var(--term-bg); color: #8aa3a5; margin-top: 40px; }
.site-foot .wrap { padding-top: 30px; padding-bottom: 30px; }
.foot-brand { color: #c4d5d3; font-family: var(--mono); margin: 0 0 12px; }
.foot-nav { display: flex; gap: 18px; flex-wrap: wrap; margin: 0 0 14px; }
.foot-nav a { color: #9bb0b2; font-size: 14px; }
.foot-nav a:hover { color: #fff; }
.foot-fine { font-size: 13px; margin: 0; }

/* ---- responsive ---- */
@media (max-width: 720px) {
  .term > .wrap { grid-template-columns: 1fr; }
  .term-card { order: -1; }
  .site-head .wrap { justify-content: center; }
}