/* relevantsearch.ai — Search Engineering Series
   Design system from README: EB Garamond body / Inter headings / JetBrains Mono code. */
@import url('fonts/fonts.css');

:root {
  --accent: #2C5282;
  --accent-soft: #3A6BA5;
  --ink: #1A202C;
  --muted: #4A5568;
  --rule: #CBD5E0;
  --code-bg: #F7FAFC;
  --bg: #FFFFFF;
  --bg-alt: #F7FAFC;
  --card: #FFFFFF;
  --shadow: 0 1px 3px rgba(26,32,44,.08), 0 8px 24px rgba(26,32,44,.05);
  /* categorical palette (also used by the diagrams) */
  --c-process: #DCE7F0; --c-tool: #FFF4D5; --c-gate: #D5F0D5;
  --c-human: #FDE5EC; --c-memory: #E8ECF1; --c-highlight: #FFE8C2; --c-fail: #FBE4E4;
  --serif: 'EB Garamond', Georgia, 'Times New Roman', serif;
  --sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --mono: 'JetBrains Mono', 'SF Mono', Menlo, Consolas, monospace;
  --maxw: 1180px;
}
[data-theme="dark"] {
  --accent: #7FA8D9; --accent-soft: #9CC0E8;
  --ink: #E2E8F0; --muted: #94A3B8; --rule: #2D3748;
  --code-bg: #0F1722; --bg: #0B1018; --bg-alt: #0F1722; --card: #131C28;
  --shadow: 0 1px 3px rgba(0,0,0,.4), 0 8px 24px rgba(0,0,0,.35);
  --c-process:#22364a; --c-tool:#42381a; --c-gate:#1f3a24; --c-human:#41212e;
  --c-memory:#262d3a; --c-highlight:#43341a; --c-fail:#3f2222;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 84px; }
body {
  margin: 0; background: var(--bg); color: var(--ink);
  font-family: var(--serif); font-size: 19px; line-height: 1.66;
  -webkit-font-smoothing: antialiased; text-rendering: optimizeLegibility;
}
.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }

/* ---- header ---- */
.site-head {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: saturate(1.4) blur(10px);
  border-bottom: 1px solid var(--rule);
}
.site-head .wrap { display: flex; align-items: center; gap: 28px; height: 64px; }
.brand { font-family: var(--sans); font-weight: 800; letter-spacing: -.02em;
  font-size: 18px; color: var(--ink); text-decoration: none; white-space: nowrap; }
.brand .dot { color: var(--accent); }
.nav { display: flex; gap: 22px; margin-left: auto; align-items: center;
  font-family: var(--sans); font-size: 14.5px; font-weight: 500; }
.nav a { color: var(--muted); text-decoration: none; padding: 6px 2px; border-bottom: 2px solid transparent; }
.nav a:hover { color: var(--ink); }
.nav a.active { color: var(--accent); border-bottom-color: var(--accent); }
.icon-btn { background: none; border: 1px solid var(--rule); color: var(--muted);
  border-radius: 8px; width: 36px; height: 36px; cursor: pointer; font-size: 15px;
  display: inline-flex; align-items: center; justify-content: center; }
.icon-btn:hover { color: var(--accent); border-color: var(--accent); }
.menu-btn { display: none; }

/* ---- typography ---- */
h1,h2,h3,h4 { font-family: var(--sans); color: var(--ink); line-height: 1.2; letter-spacing: -.02em; }
h1 { font-size: 2.6rem; font-weight: 800; margin: 0 0 .4em; }
h2 { font-size: 1.7rem; font-weight: 700; margin: 2.2em 0 .5em; }
h3 { font-size: 1.25rem; font-weight: 700; margin: 1.8em 0 .4em; }
p { margin: 0 0 1.05em; }
a { color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 2px; }
a:hover { color: var(--accent-soft); }
code { font-family: var(--mono); font-size: .82em; background: var(--code-bg);
  border: 1px solid var(--rule); border-radius: 4px; padding: .08em .35em; }
pre { background: var(--code-bg); border: 1px solid var(--rule); border-radius: 10px;
  padding: 18px 20px; overflow-x: auto; margin: 1.2em 0; }
pre code { font-size: 13.5px; background: none; border: 0; padding: 0; line-height: 1.6;
  display: block; color: var(--ink); }
blockquote { border-left: 3px solid var(--accent); margin: 1.2em 0; padding: .2em 0 .2em 18px;
  color: var(--muted); font-style: italic; }
hr { border: 0; border-top: 1px solid var(--rule); margin: 2.5em 0; }
ul, ol { margin: 0 0 1.1em; padding-left: 1.3em; }
li { margin: .3em 0; }
figure { margin: 1.6em 0; text-align: center; }
figure img { max-width: min(700px, 100%); height: auto; border: 1px solid var(--rule);
  border-radius: 10px; background: #fff; }
figcaption { font-size: .82em; color: var(--muted); margin-top: .6em; font-style: italic; }
table { border-collapse: collapse; width: 100%; margin: 1.4em 0; font-size: .82em;
  font-family: var(--sans); }
th, td { border: 1px solid var(--rule); padding: 9px 12px; text-align: left; vertical-align: top; }
th { background: var(--bg-alt); font-weight: 600; }
.svg-link { font-family: var(--sans); font-size: .72em; }

/* ---- footer ---- */
.site-foot { border-top: 1px solid var(--rule); margin-top: 80px; background: var(--bg-alt);
  font-family: var(--sans); font-size: 14px; color: var(--muted); }
.site-foot .wrap { padding: 44px 24px; display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 32px; }
.site-foot h4 { font-size: 12px; text-transform: uppercase; letter-spacing: .08em; color: var(--muted); margin: 0 0 12px; }
.site-foot a { color: var(--muted); text-decoration: none; display: block; margin: 6px 0; }
.site-foot a:hover { color: var(--accent); }
.foot-brand { font-weight: 800; font-size: 16px; color: var(--ink); }
.foot-bottom { border-top: 1px solid var(--rule); }
.foot-bottom .wrap { padding: 18px 24px; display: flex; justify-content: space-between; font-size: 13px; }

/* ---- tags / chips ---- */
.tag { font-family: var(--sans); font-size: 11.5px; font-weight: 600; padding: 3px 9px;
  border-radius: 100px; display: inline-block; color: #1A202C; white-space: nowrap; }
[data-theme="dark"] .tag { color: #0B1018; }
.vol-1{background:var(--c-process)} .vol-2{background:var(--c-tool)} .vol-3{background:var(--c-gate)}
.vol-4{background:var(--c-human)} .vol-5{background:var(--c-memory)} .vol-6{background:var(--c-highlight)}
.vol-7{background:var(--c-fail)} .vol-8{background:#D6E4D0} .vol-9{background:#E0D6F0}

/* ---- home ---- */
.hero { padding: 72px 0 36px; border-bottom: 1px solid var(--rule); }
.hero .eyebrow { font-family: var(--sans); font-weight: 600; font-size: 13px; letter-spacing: .1em;
  text-transform: uppercase; color: var(--accent); margin-bottom: 16px; }
.hero h1 { font-size: 3.3rem; max-width: 16ch; }
.hero .lede { font-size: 1.32rem; color: var(--muted); max-width: 58ch; margin-top: .2em; }
.hero .cta { margin-top: 28px; display: flex; gap: 14px; flex-wrap: wrap; }
.btn { font-family: var(--sans); font-weight: 600; font-size: 15px; padding: 12px 22px;
  border-radius: 10px; text-decoration: none; display: inline-block; border: 1px solid var(--accent); }
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: var(--accent-soft); color: #fff; }
.btn-ghost { color: var(--accent); background: transparent; }
.btn-ghost:hover { background: var(--code-bg); }
.stat-row { display: flex; gap: 40px; margin-top: 40px; flex-wrap: wrap; font-family: var(--sans); }
.stat b { display: block; font-size: 2rem; font-weight: 800; color: var(--ink); line-height: 1; }
.stat span { font-size: 13px; color: var(--muted); }

.section-h { font-family: var(--sans); margin: 64px 0 8px; }
.section-h .k { font-size: 13px; font-weight: 600; letter-spacing: .1em; text-transform: uppercase; color: var(--accent); }
.section-sub { color: var(--muted); max-width: 60ch; margin-bottom: 28px; }

.vol-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.vol-card { background: var(--card); border: 1px solid var(--rule); border-radius: 14px;
  padding: 24px; text-decoration: none; color: var(--ink); display: flex; flex-direction: column;
  box-shadow: var(--shadow); transition: transform .15s, border-color .15s; }
.vol-card:hover { transform: translateY(-3px); border-color: var(--accent); }
.vol-card .num { font-family: var(--mono); font-size: 13px; color: var(--muted); }
.vol-card h3 { margin: 8px 0 6px; font-size: 1.18rem; }
.vol-card p { font-family: var(--sans); font-size: 14px; color: var(--muted); margin: 0; line-height: 1.5; }
.vol-card .meta { margin-top: auto; padding-top: 16px; font-family: var(--sans); font-size: 12.5px;
  color: var(--muted); display: flex; gap: 14px; }

.cta-band { background: var(--accent); color: #fff; border-radius: 18px; padding: 48px;
  margin: 72px 0; display: flex; align-items: center; justify-content: space-between; gap: 30px; flex-wrap: wrap; }
.cta-band h2 { color: #fff; margin: 0 0 8px; }
.cta-band p { color: rgba(255,255,255,.85); font-family: var(--sans); margin: 0; max-width: 52ch; }
.cta-band .btn { background: #fff; color: var(--accent); border-color: #fff; white-space: nowrap; }

/* ---- volume page layout ---- */
.vol-layout { display: grid; grid-template-columns: 260px minmax(0,1fr); gap: 48px; padding-top: 36px; }
.toc { position: sticky; top: 84px; align-self: start; max-height: calc(100vh - 100px);
  overflow-y: auto; font-family: var(--sans); font-size: 13.5px; padding-right: 8px; }
.toc .toc-title { font-weight: 700; font-size: 12px; text-transform: uppercase; letter-spacing: .08em;
  color: var(--muted); margin-bottom: 12px; }
.toc a { display: block; color: var(--muted); text-decoration: none; padding: 3px 0; line-height: 1.4; }
.toc a:hover, .toc a.active { color: var(--accent); }
.toc .lvl-section { font-weight: 600; color: var(--ink); margin-top: 14px; }
.toc .lvl-entry { padding-left: 12px; border-left: 1px solid var(--rule); }
.article { min-width: 0; }
.vol-header { border-bottom: 1px solid var(--rule); padding-bottom: 22px; margin-bottom: 8px; }
.vol-header .kicker { font-family: var(--sans); font-size: 13px; font-weight: 600; color: var(--accent);
  letter-spacing: .08em; text-transform: uppercase; }
.vol-header h1 { margin: 10px 0 6px; }
.vol-nav { display: flex; justify-content: space-between; margin: 56px 0 0; gap: 16px;
  font-family: var(--sans); font-size: 14px; border-top: 1px solid var(--rule); padding-top: 24px; }
.vol-nav a { text-decoration: none; }

/* ---- pattern card ---- */
.pattern { background: var(--card); border: 1px solid var(--rule); border-radius: 14px;
  padding: 26px 28px; margin: 22px 0; box-shadow: var(--shadow); scroll-margin-top: 84px; }
.pattern > h3 { margin-top: 0; display: flex; align-items: baseline; gap: 12px; flex-wrap: wrap; }
.pattern .classify { font-family: var(--sans); font-size: 13.5px; color: var(--muted); font-style: italic;
  border-left: 3px solid var(--rule); padding-left: 12px; margin: 4px 0 16px; }
.field { margin: 14px 0; }
.field-label { font-family: var(--sans); font-size: 11.5px; font-weight: 700; letter-spacing: .07em;
  text-transform: uppercase; color: var(--accent); display: block; margin-bottom: 4px; }
.field-source { color: var(--muted); font-size: .92em; }
.anchor-link { font-family: var(--sans); font-size: 13px; color: var(--rule); text-decoration: none;
  font-weight: 400; opacity: 0; }
.pattern:hover .anchor-link { opacity: 1; }
.code-label { font-family: var(--sans); font-size: 11.5px; font-weight: 700; letter-spacing: .06em;
  text-transform: uppercase; color: var(--muted); margin: 1.2em 0 .3em; }

/* ---- patterns index ---- */
.filters { display: flex; flex-wrap: wrap; gap: 8px; margin: 18px 0 6px; font-family: var(--sans); }
.chip { font-size: 13px; padding: 6px 14px; border-radius: 100px; border: 1px solid var(--rule);
  background: var(--card); color: var(--muted); cursor: pointer; }
.chip.active { background: var(--accent); color: #fff; border-color: var(--accent); }
.search-inline { width: 100%; font-family: var(--sans); font-size: 16px; padding: 13px 16px;
  border: 1px solid var(--rule); border-radius: 10px; background: var(--card); color: var(--ink); margin: 14px 0; }
.search-inline:focus { outline: none; border-color: var(--accent); }
.pcount { font-family: var(--sans); font-size: 13px; color: var(--muted); margin-bottom: 18px; }
.pgrid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 18px; }
.pcard { background: var(--card); border: 1px solid var(--rule); border-radius: 12px; padding: 20px 22px;
  text-decoration: none; color: var(--ink); display: flex; flex-direction: column; transition: border-color .15s; }
.pcard:hover { border-color: var(--accent); }
.pcard h3 { margin: 8px 0 8px; font-size: 1.08rem; }
.pcard p { font-family: var(--sans); font-size: 13.5px; color: var(--muted); margin: 0; line-height: 1.5; }
.pcard .ptags { display: flex; gap: 8px; flex-wrap: wrap; align-items: center; }
.pcard .psec { font-family: var(--sans); font-size: 11.5px; color: var(--muted); }
.empty-msg { font-family: var(--sans); color: var(--muted); padding: 40px 0; text-align: center; }

/* ---- search overlay ---- */
.search-overlay { position: fixed; inset: 0; z-index: 100; background: rgba(11,16,24,.55);
  backdrop-filter: blur(3px); display: none; padding-top: 12vh; }
.search-overlay.open { display: block; }
.search-box { max-width: 640px; margin: 0 auto; background: var(--bg); border-radius: 14px;
  box-shadow: 0 20px 60px rgba(0,0,0,.4); overflow: hidden; }
.search-box input { width: 100%; border: 0; border-bottom: 1px solid var(--rule); padding: 20px 22px;
  font-size: 18px; font-family: var(--sans); background: var(--bg); color: var(--ink); }
.search-box input:focus { outline: none; }
.search-results { max-height: 56vh; overflow-y: auto; }
.search-results a { display: block; padding: 14px 22px; text-decoration: none; color: var(--ink);
  border-bottom: 1px solid var(--rule); }
.search-results a:hover, .search-results a.sel { background: var(--bg-alt); }
.search-results .r-title { font-family: var(--sans); font-weight: 600; font-size: 15px; }
.search-results .r-ctx { font-family: var(--sans); font-size: 12.5px; color: var(--muted); margin-top: 2px; }
.search-results mark { background: var(--c-highlight); color: inherit; padding: 0 1px; border-radius: 2px; }
.search-hint { padding: 10px 22px; font-family: var(--sans); font-size: 12px; color: var(--muted);
  display: flex; gap: 14px; border-top: 1px solid var(--rule); }
kbd { font-family: var(--mono); font-size: 11px; border: 1px solid var(--rule); border-radius: 4px;
  padding: 1px 5px; background: var(--bg-alt); }

/* ---- prose container width ---- */
.prose { max-width: 72ch; }
.prose.full { max-width: none; }

/* ---- responsive ---- */
@media (max-width: 900px) {
  body { font-size: 18px; }
  .vol-grid, .pgrid { grid-template-columns: 1fr; }
  .vol-layout { grid-template-columns: 1fr; }
  .toc { display: none; }
  .hero h1 { font-size: 2.4rem; }
  .nav { display: none; }
  .nav.open { display: flex; position: absolute; top: 64px; left: 0; right: 0; flex-direction: column;
    background: var(--bg); border-bottom: 1px solid var(--rule); padding: 16px 24px; gap: 14px; }
  .menu-btn { display: inline-flex; }
  .site-foot .wrap { grid-template-columns: 1fr; }
  .cta-band { padding: 32px; }
  .hero { padding: 48px 0 28px; }
}
@media print {
  .site-head, .site-foot, .toc, .search-overlay, .vol-nav, .cta-band, .filters, .search-inline { display: none; }
  .vol-layout { grid-template-columns: 1fr; } body { font-size: 12pt; }
  .pattern, .vol-card { box-shadow: none; break-inside: avoid; }
}