@import url("https://fonts.googleapis.com/css2?family=Fira+Code:wght@400;600&family=IBM+Plex+Sans:wght@400;600;700&display=swap");

/* ── v2 vocabulary (see SKILL.md §6, references/rules.md) ──────────────────
   Hue bindings — one hue = one meaning:
     --accent #1866b4  links + navigation ONLY
     --anchor #6f42c1  semantic scan anchors (.key) + callouts — never a link
     green / amber / red  status encodings only, keyed where used
   Weights: 700 headings · 600 labels/th/inline emphasis · 400 body.
   Type scale: 28 title · 18 section · 16.5 card head · 16 body ·
               14.5 secondary · 13 quiet.                                   */

:root {
  --bg: #f4f6f9;
  --surface: #fff;
  --ink: #1b2333;
  --muted: #5b6577;
  --line: #e3e8ef;
  --accent: #1866b4;
  --accent-soft: #e9f2fb;
  --anchor: #6f42c1;
  --anchor-soft: #f4eefb;
  --green: #2b8a3e;
  --green-soft: #e8f5ec;
  --amber: #9a6700;
  --amber-soft: #fff6e0;
  --red: #c0392b;
  --red-soft: #fdeceb;
  --code-bg: #f8f9fc;
  --font-prose: "IBM Plex Sans", "Helvetica Neue", sans-serif;
  --font-mono: "Fira Code", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --font-system: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.55 var(--font-prose);
}
main { max-width: 2200px; margin: 0 auto; padding: 40px 56px 80px; }
main.wide { max-width: none; }  /* ultrawide multi-panel docs; page-level horizontal scroll is fine */
h1 { margin: 0 0 4px; font: 700 28px/1.25 var(--font-system); }
h2 { margin: 0; color: var(--ink); font-family: var(--font-system); }
h3 { margin: 0 0 8px; color: var(--ink); font: 700 16.5px/1.3 var(--font-system); }
p { margin: 0 0 12px; }
a { color: var(--accent); }
.dek { margin: 2px 0 4px; font: 400 16px/1.5 var(--font-prose); }        /* ≤15 words, no box */
.byline { margin: 0 0 26px; color: var(--muted); font: 400 13px/1.55 var(--font-system); letter-spacing: .03em; }
.key { color: var(--anchor); }                                            /* scan anchor ≠ link */
.aside, .small { display: block; margin: 2px 0 12px; color: var(--muted); font-size: 13px; }
.card .id, nav.toc .g { font-family: var(--font-system); }

/* Question-first section heads: the h2 IS the reader's question (sentence case);
   the optional .tag is the demoted category label. */
.section-head,
.layer-head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin: 46px 0 20px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--line);
}
.section-head h2,
.layer-head h2 { font: 700 18px/1.3 var(--font-system); }
.section-head .tag,
.layer-head .tag { color: var(--muted); font: 600 11px/1.7 var(--font-mono); text-transform: uppercase; letter-spacing: .05em; }
.layer-head .n { color: var(--accent); font-size: 26px; font-weight: 700; }

/* Opt-in summary box — BELOW the first substantive content, one short
   paragraph, only when it changes the reader's next action. No accent bar:
   it must not become a second hero. */
.summary { margin: 18px 0; padding: 14px 18px; border: 1px solid var(--line); border-radius: 10px; background: var(--surface); font-size: 15px; }

.grid-2, .grid-3, .grid-4,
.cols2, .cols3, .cols4,
.l1, .l2, .l3 { display: grid; gap: 18px; }
.grid-2, .cols2, .l3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid-3, .cols3, .l2 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid-4, .cols4, .l1 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
.full { grid-column: 1 / -1; }

/* ── Parallel panels (ultrawide layout system, references/layout.md) ──────
   Side-by-side documents-in-miniature for cross-referenceable sections —
   NOT snaking columns. Single-column stack (DOM order) below 1600px.
   Sticky panel heads keep each panel's question in view while scrolling. */
.panels { display: grid; grid-template-columns: 1fr; gap: 32px; align-items: start; margin: 18px 0; }
.panels > .panel { min-width: 0; }
.panel > .section-head { position: sticky; top: 0; z-index: 2; margin-top: 0; padding-top: 8px; background: var(--bg); }
@media (min-width: 1600px) {
  .panels.p2 { grid-template-columns: repeat(2, minmax(520px, 1fr)); }
  .panels.p3 { grid-template-columns: repeat(3, minmax(460px, 1fr)); }
  .panels.p4 { grid-template-columns: repeat(4, minmax(420px, 1fr)); }
  /* Named slots: pin visual order independent of DOM order (DOM order = reading/fallback order). */
  .panels.p2 { grid-template-areas: "a b"; }
  .panels.p3 { grid-template-areas: "a b c"; }
  .panels.p4 { grid-template-areas: "a b c d"; }
  .panels.slotted > .panel.a { grid-area: a; }
  .panels.slotted > .panel.b { grid-area: b; }
  .panels.slotted > .panel.c { grid-area: c; }
  .panels.slotted > .panel.d { grid-area: d; }
  .panels:not(.slotted) > .panel.span2 { grid-column: span 2; }
}

.card {
  padding: 18px 22px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--surface);
}
.card .decision { margin-bottom: 6px; font: 700 16.5px/1.4 var(--font-system); }
.card .why { color: var(--muted); font-size: 13px; }
.card ul { margin: 6px 0 0; padding-left: 18px; color: var(--muted); font-size: 14.5px; }
.card li { margin-bottom: 6px; }
.card li::marker { color: var(--accent); font-weight: 700; }
.card b, .card strong { color: var(--ink); }

.diagram,
figure.panel {
  margin-top: 18px;
  padding: 24px 28px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--surface);
}
.drow, .flow { display: flex; align-items: stretch; gap: 10px; }
.dnode, .flow .node {
  flex: 1;
  padding: 10px 14px;
  border: 1.5px solid #9aa7bd;
  border-radius: 10px;
  background: #fbfcfe;
  text-align: center;
}
.dnode small, .flow .node small { display: block; margin-top: 3px; color: var(--muted); font-size: 13px; }
.dnode.ext, .flow .node.ext { border-style: dashed; }
.dnode.hot, .flow .node.hot { border-color: var(--green); background: var(--green-soft); }
.dnode.warn, .flow .node.warn { border-color: var(--amber); background: var(--amber-soft); }
.dnode.bad, .flow .node.bad { border-color: var(--red); background: var(--red-soft); }
.darr, .flow .arr { display: flex; align-items: center; color: #8b96a9; font-size: 20px; }
.dcaption, figcaption { margin-top: 10px; color: var(--muted); font-size: 13px; }

table { width: 100%; border: 1px solid var(--line); border-collapse: collapse; background: var(--surface); font-size: 14.5px; }
th, td { padding: 8px 12px; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
th { background: #f1f4f9; color: var(--muted); font: 600 11.5px/1.4 var(--font-system); letter-spacing: .06em; text-transform: uppercase; }
tr:last-child td { border-bottom: 0; }

code {
  padding: 0 5px;
  border: 1px solid var(--line);
  border-radius: 5px;
  background: #eef1f6;
  font: 75%/1.55 var(--font-mono);
}
.codeblock { margin: 14px 0; overflow: hidden; border: 1px solid var(--line); border-radius: 10px; background: var(--surface); }
.codeblock .cb-head { display: flex; justify-content: space-between; gap: 10px; padding: 7px 14px; border-bottom: 1px solid var(--line); background: #f1f4f9; color: var(--muted); font: 12px/1.4 var(--font-system); }
.codeblock pre { margin: 0; padding: 14px 16px; overflow-x: auto; background: var(--code-bg); font-family: var(--font-mono); }
.codeblock pre code { padding: 0; border: 0; background: transparent; font-size: 75%; line-height: 1.55; }
.chipcloud .adapter { font: 75%/1.55 var(--font-mono); }

/* One callout variant. It carries the anchor hue (a boxed key point is scan-
   anchor material); status colors belong to keyed chips/cards, not callouts. */
.callout { margin: 14px 0; padding: 12px 18px; border-left: 4px solid var(--anchor); border-radius: 0 8px 8px 0; background: var(--anchor-soft); font-size: 14.5px; }

/* Colophon: ALL process metadata (sources, provenance, ids, honest scope
   notes). Reader-relevant honesty stays in context above, in plain language. */
.colophon { margin-top: 46px; padding-top: 14px; border-top: 1px solid var(--line); color: var(--muted); font-size: 13px; }
.colophon code { background: var(--code-bg); }

body.with-toc { display: grid; grid-template-columns: 270px minmax(0, 1fr); }
nav.toc { position: sticky; top: 0; height: 100vh; overflow-y: auto; padding: 28px 20px; border-right: 1px solid var(--line); background: var(--surface); font-size: 14.5px; }
nav.toc .brand { margin-bottom: 12px; font-size: 15px; font-weight: 700; }
nav.toc .brand { font-family: var(--font-system); }
nav.toc a { display: block; margin-bottom: 2px; padding: 6px 10px; border-radius: 7px; color: var(--ink); text-decoration: none; }
nav.toc a:hover { background: var(--accent-soft); color: var(--accent); }

@media (max-width: 1500px) {
  .grid-3, .grid-4, .cols3, .cols4, .l1, .l2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 900px) {
  body.with-toc { display: block; }
  nav.toc { display: none; }
  main { padding: 24px; }
  .grid-2, .grid-3, .grid-4, .cols2, .cols3, .cols4, .l1, .l2, .l3 { grid-template-columns: 1fr; }
  .drow, .flow { flex-direction: column; }
}