styles.css

/* ============================================================
   RL-for-LLMs Wiki Reader — styles
   Editorial palette borrowed from the project dashboard.
   ============================================================ */

* { margin: 0; padding: 0; box-sizing: border-box; }

:root {
  --bg: #fafafa;
  --bg-soft: #f4f4f4;
  --bg-card: #ffffff;
  --bg-code: #f6f7f9;
  --border: #ddd;
  --border-soft: #eee;
  --ink: #1a1a1a;
  --ink-2: #2a2a2a;
  --ink-3: #444;
  --muted: #555;
  --muted-2: #777;
  --muted-3: #888;
  --muted-4: #999;
  --muted-5: #aaa;
  --accent: #0f3787;        /* deep editorial blue */
  --accent-deep: #0a275f;
  --accent-soft: #dde6f5;
  --accent-hover-row: #c8d6ee;
  --hl-bg: #0f3787;         /* search-hit rectangle */
  --hl-ink: #ffffff;
  --good: #1c7c3f;
  --warn: #9a6b00;
  --danger: #a12d2d;
  --shadow: 0 1px 2px rgba(0,0,0,0.04), 0 2px 8px rgba(0,0,0,0.03);
  --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
  --sans: "Inter", "Helvetica Neue", system-ui, sans-serif;
  --sidebar-w: 280px;
  --aside-w: 248px;
}

[data-theme="dark"] {
  --bg: #15171a;
  --bg-soft: #1b1e22;
  --bg-card: #1e2228;
  --bg-code: #14181d;
  --border: #2e343c;
  --border-soft: #262b31;
  --ink: #e9ecf0;
  --ink-2: #dfe3e8;
  --ink-3: #c4cad2;
  --muted: #aab2bd;
  --muted-2: #8b94a0;
  --muted-3: #79828e;
  --muted-4: #69707b;
  --muted-5: #585f69;
  --accent: #8fb2f0;
  --accent-deep: #b6cdf7;
  --accent-soft: #20304d;
  --accent-hover-row: #28395a;
  --hl-bg: #4f7fe0;
  --hl-ink: #ffffff;
  --good: #6fcf8f;
  --warn: #e0b15a;
  --danger: #e08585;
  --shadow: 0 1px 2px rgba(0,0,0,0.35), 0 2px 10px rgba(0,0,0,0.25);
}

html { scroll-behavior: smooth; }

body {
  font-family: var(--sans);
  font-size: 14px;
  font-weight: 300;
  line-height: 1.65;
  color: var(--ink);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

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

/* ── Top bar ───────────────────────────────────────────── */
.topbar {
  position: sticky; top: 0; z-index: 50;
  display: flex; align-items: center; gap: 18px;
  padding: 12px 22px;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}
.brand { display: flex; align-items: baseline; gap: 10px; cursor: pointer; min-width: 0; }
.brand .logo {
  font-family: var(--mono); font-weight: 600; font-size: 16px;
  letter-spacing: 0.5px; color: var(--ink); white-space: nowrap;
}
.brand .logo .dot { color: var(--accent); }
.brand .tag {
  font-size: 11.5px; color: var(--muted-2); font-weight: 300;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.counts {
  font-family: var(--mono); font-size: 11px; font-weight: 500;
  color: var(--muted-2); letter-spacing: 0.3px; font-variant-numeric: tabular-nums;
  white-space: nowrap;
}
.counts .n { color: var(--accent); font-weight: 600; }
.counts .sep { color: var(--muted-4); margin: 0 8px; }
.topbar .spacer { flex: 1 1 auto; }
.toolbar { display: flex; align-items: center; gap: 7px; }
.btn {
  font-family: var(--mono); font-size: 10.5px; font-weight: 400; letter-spacing: 0.4px;
  padding: 5px 10px; border: 1px solid var(--border); border-radius: 4px;
  background: var(--bg-card); color: var(--muted); cursor: pointer;
  transition: all .15s; white-space: nowrap; text-decoration: none;
  display: inline-flex; align-items: center; gap: 5px;
}
.btn:hover { border-color: var(--muted-3); color: var(--ink); }
.icon-btn { padding: 5px 8px; font-size: 13px; line-height: 1; }
/* internal nav (sources) — tinted to read as primary, not an external link */
.btn-sources { background: var(--accent-soft); color: var(--accent-deep); border-color: transparent; font-weight: 500; }
.btn-sources:hover { background: var(--accent-hover-row); color: var(--accent-deep); border-color: transparent; }
.btn-sources.active { background: var(--accent); color: #fff; }
[data-theme="dark"] .btn-sources.active { color: #0b1220; }

/* ── Mobile sidebar toggle ─────────────────────────────── */
.menu-toggle { display: none; }

/* ── Layout ────────────────────────────────────────────── */
.layout {
  display: grid;
  grid-template-columns: var(--sidebar-w) minmax(0, 1fr);
  align-items: start;
}
@media (min-width: 1180px) {
  .layout.has-aside {
    grid-template-columns: var(--sidebar-w) minmax(0, 1fr) var(--aside-w);
  }
}

/* ── Sidebar (navigation) ──────────────────────────────── */
.sidebar {
  position: sticky; top: 53px; align-self: start;
  height: calc(100vh - 53px);
  overflow-y: auto;
  border-right: 1px solid var(--border);
  padding: 16px 14px 40px;
  background: var(--bg);
}
/* sidebar section header — "Topics" (the first-class citizen) */
.side-head {
  font-family: var(--mono); font-size: 12px; font-weight: 600; letter-spacing: 1px;
  text-transform: uppercase; color: var(--ink-2); margin: 2px 2px 12px;
}

.search-wrap { position: relative; margin-bottom: 16px; }
.search {
  width: 100%; font-family: var(--sans); font-size: 13px;
  padding: 8px 44px 8px 28px; border: 1px solid var(--border); border-radius: 6px;
  background: var(--bg-card); color: var(--ink);
}
.search:focus { outline: none; border-color: var(--accent); }
.search-wrap::before {
  content: "⌕"; position: absolute; left: 9px; top: 50%; transform: translateY(-50%);
  color: var(--muted-3); font-size: 15px;
}
/* the ⌘K badge on the search box: click (or ⌘K) → focus the search input */
.search-k {
  position: absolute; right: 7px; top: 50%; transform: translateY(-50%);
  font-family: var(--mono); font-size: 10px; padding: 2px 6px; border-radius: 4px;
  border: 1px solid var(--border); background: var(--bg-soft); color: var(--muted-3);
  cursor: pointer; transition: all .12s;
}
.search-k:hover { border-color: var(--accent); color: var(--accent-deep); }
/* once a query is entered, the badge becomes a ✕ clear button */
.search-k.is-clear { font-family: var(--sans); font-size: 12px; line-height: 1; padding: 3px 6.5px; }
.search-k.is-clear:hover { background: var(--accent-soft); }

.nav-group { margin-bottom: 14px; }
.nav-group-title {
  font-family: var(--mono); font-size: 9.5px; font-weight: 600;
  text-transform: uppercase; letter-spacing: 1.4px; color: var(--muted-3);
  padding: 4px 8px; margin-bottom: 2px;
  display: flex; justify-content: space-between; align-items: center;
}
.nav-group-title .c { color: var(--muted-4); font-weight: 500; }
.nav-item {
  display: block; padding: 5px 9px; border-radius: 5px;
  font-size: 12.5px; color: var(--ink-3); cursor: pointer;
  line-height: 1.35; transition: background .12s, color .12s;
  border-left: 2px solid transparent;
}
.nav-item:hover { background: var(--bg-soft); color: var(--ink); }
.nav-item.active {
  background: var(--accent-soft); color: var(--accent-deep);
  border-left-color: var(--accent); font-weight: 500;
}
.nav-item .ni-sub {
  display: block; font-family: var(--mono); font-size: 9.5px;
  color: var(--muted-4); margin-top: 1px; letter-spacing: 0.2px;
}
/* content-search: a matched-body excerpt under the topic name, query bolded */
.nav-item .nav-item-title { display: block; }
.nav-item .nav-item-title b { color: var(--accent-deep); font-weight: 600; }
.nav-item .nav-snippets { display: block; margin-top: 2px; }
.nav-item .nav-snippet {
  display: block; margin-top: 2px; padding: 2px 6px; font-size: 11px; line-height: 1.4;
  color: var(--muted-3); font-weight: 400; cursor: pointer;
  border-left: 2px solid var(--border); border-radius: 0 4px 4px 0;
  transition: background .12s, border-color .12s, color .12s;
}
.nav-item .nav-snippet:hover { background: var(--accent-soft); border-left-color: var(--accent); color: var(--ink); }
.nav-item .nav-snippet b { color: var(--accent-deep); font-weight: 600; }
.nav-item .nav-snippet.more { font-style: italic; cursor: default; border-left-color: transparent; color: var(--muted-4); }
.nav-item .nav-snippet.more:hover { background: none; }
.nav-hit-count {
  display: inline-block; margin-left: 5px; padding: 0 5px; font-family: var(--mono);
  font-size: 9px; line-height: 15px; vertical-align: 1px; border-radius: 8px;
  background: var(--accent-soft); color: var(--accent-deep); font-weight: 600;
}
.nav-empty { color: var(--muted-4); font-size: 11.5px; padding: 8px; font-style: italic; }
.mini-spin { display: inline-block; width: 10px; height: 10px; vertical-align: -1px; margin-right: 4px;
  border: 1.5px solid var(--border); border-top-color: var(--accent); border-radius: 50%; animation: spin .7s linear infinite; }

/* ── Main content ──────────────────────────────────────── */
.main { min-width: 0; padding: 26px 38px 80px; }
@media (max-width: 760px) { .main { padding: 20px 18px 60px; } }

.crumbs {
  font-family: var(--mono); font-size: 10.5px; color: var(--muted-3);
  letter-spacing: 0.3px; margin-bottom: 14px; display: flex; gap: 6px; flex-wrap: wrap; align-items: center;
}
.crumbs a { color: var(--muted-2); }
.crumbs a:hover { color: var(--accent); }
.crumbs .sep { color: var(--muted-5); }

/* doc header */
/* single reading column for topic articles (no right rail) */
.doc { max-width: 820px; margin: 0 auto; }
.doc .prose { max-width: none; }

/* collapsible disclosures used in the article flow (Contents, Open questions) */
.disclosure { border: 1px solid var(--border); border-radius: 9px; background: var(--bg-card); margin: 14px 0; overflow: hidden; }
.disclosure > summary {
  list-style: none; cursor: pointer; padding: 10px 14px; display: flex; align-items: center; gap: 8px;
  font-family: var(--mono); font-size: 12px; font-weight: 600; letter-spacing: 0.4px; text-transform: uppercase; color: var(--ink-3);
}
.disclosure > summary::-webkit-details-marker { display: none; }
.disclosure > summary:hover { color: var(--ink); }
.disclosure > summary::after { content: "▸"; margin-left: auto; color: var(--muted-4); transition: transform .15s; }
.disclosure[open] > summary::after { transform: rotate(90deg); }
.disclosure .disc-ic { color: var(--accent); font-weight: 700; }
.disclosure .disc-n { color: var(--muted-4); font-weight: 500; }
.disclosure.oq-d { border-left: 3px solid var(--accent); }
.disclosure .oq-list, .disclosure .toc { padding: 2px 16px 14px; }
.disclosure .toc { display: block; }
.disclosure .toc a { display: block; font-size: 12.5px; color: var(--muted); padding: 3px 0 3px 10px; border-left: 2px solid var(--border-soft); }
.disclosure .toc a.h3 { padding-left: 22px; font-size: 11.5px; }
.disclosure .toc a:hover { color: var(--accent); border-left-color: var(--accent); }

/* references (sources cited), at the end of the article */
.refs-section { margin: 40px 0 8px; padding-top: 20px; border-top: 1px solid var(--border); }
.refs-h { font-family: var(--mono); font-size: 15px; font-weight: 600; color: var(--ink); margin-bottom: 12px; display: flex; align-items: baseline; gap: 8px; }
.refs-h .refs-n { font-size: 11px; color: var(--muted-4); font-weight: 500; }
.refs-list { list-style: decimal; margin: 0 0 0 26px; padding: 0; }
.refs-list li { margin: 5px 0; font-size: 13px; line-height: 1.5; }
.refs-list li::marker { color: var(--muted-4); font-family: var(--mono); font-size: 11px; }
.ref-id { font-family: var(--mono); font-size: 11.5px; color: var(--accent); border-bottom: none; }
.ref-id:hover { border-bottom: 1px solid var(--accent); }
.ref-title { color: var(--ink-3); margin-left: 8px; }
.ref-ext { color: var(--muted-4); border-bottom: none; }
.page-links { margin: 22px 0 0; display: flex; gap: 16px; font-family: var(--mono); font-size: 11px; }
.page-links a { color: var(--muted-3); }
.page-links a:hover { color: var(--accent); }

/* figures — images, inline SVG diagrams, generated plots */
.prose .fig { margin: 24px 0; text-align: center; }
.prose .fig img, .prose .fig svg { max-width: 100%; height: auto; }
/* raster/exported-SVG figures get a light matte so plots/diagrams stay legible in dark mode */
.prose .fig img { background: #fff; padding: 12px; border-radius: 8px; border: 1px solid var(--border); box-shadow: var(--shadow); }
.prose .fig figcaption { font-size: 12px; color: var(--muted-2); margin: 10px auto 0; line-height: 1.5; text-align: center; max-width: 640px; }
.prose .fig.fig-broken { display: none; }   /* hide a figure whose image failed to load */

.doc-head { margin-bottom: 18px; padding-bottom: 16px; border-bottom: 1px solid var(--border); }
.doc-kicker {
  font-family: var(--mono); font-size: 10.5px; letter-spacing: 1.5px;
  text-transform: uppercase; color: var(--accent); font-weight: 600; margin-bottom: 8px;
}
.doc-title {
  font-family: var(--mono); font-weight: 600; font-size: 26px; line-height: 1.2;
  color: var(--ink); letter-spacing: -0.2px;
}
.doc-meta-row { display: flex; flex-wrap: wrap; gap: 8px 14px; align-items: center; margin-top: 12px; }
.doc-authors { font-size: 12.5px; color: var(--muted); }
.doc-sub { font-size: 12px; color: var(--muted-2); font-family: var(--mono); }

/* badges */
.badge {
  display: inline-flex; align-items: center; gap: 5px;
  font-family: var(--mono); font-size: 10px; font-weight: 500; letter-spacing: 0.4px;
  padding: 2.5px 8px; border-radius: 20px; border: 1px solid var(--border);
  background: var(--bg-card); color: var(--muted); text-transform: uppercase;
  white-space: nowrap;
}
.badge .b-dot { width: 6px; height: 6px; border-radius: 50%; background: var(--muted-4); }
.badge.mat-comprehensive { color: var(--good); border-color: color-mix(in srgb, var(--good) 40%, var(--border)); }
.badge.mat-comprehensive .b-dot { background: var(--good); }
.badge.mat-developing { color: var(--warn); border-color: color-mix(in srgb, var(--warn) 40%, var(--border)); }
.badge.mat-developing .b-dot { background: var(--warn); }
.badge.mat-stub { color: var(--muted-2); }
.badge.mat-stub .b-dot { background: var(--muted-4); }
.badge.type { background: var(--accent-soft); color: var(--accent-deep); border-color: transparent; }

/* ── Prose (rendered markdown) ─────────────────────────── */
.prose { font-size: 14.5px; line-height: 1.75; color: var(--ink-2); max-width: 860px; }
.prose > *:first-child { margin-top: 0; }
.prose h1 { display: none; } /* title handled by doc-head */
.prose h2 {
  font-family: var(--mono); font-size: 19px; font-weight: 600; color: var(--ink);
  margin: 34px 0 12px; padding-top: 6px; letter-spacing: -0.1px;
  scroll-margin-top: 70px;
}
.prose h3 {
  font-family: var(--mono); font-size: 15.5px; font-weight: 600; color: var(--ink-2);
  margin: 26px 0 10px; scroll-margin-top: 70px;
}
.prose h4 { font-size: 14px; font-weight: 600; color: var(--ink-2); margin: 20px 0 8px; scroll-margin-top: 70px; }
.prose h2 .anchor, .prose h3 .anchor, .prose h4 .anchor {
  opacity: 0; margin-left: 8px; font-size: 0.6em; vertical-align: middle;
  transition: opacity .12s; text-decoration: none; border-bottom: none; cursor: pointer;
}
.prose h2:hover .anchor, .prose h3:hover .anchor, .prose h4:hover .anchor { opacity: 0.55; }
.prose .anchor:hover { opacity: 1 !important; }

/* page-level "copy link" button in the doc header */
.share-btn {
  margin-left: 12px; font-family: var(--mono); font-size: 9.5px; letter-spacing: 0.4px;
  padding: 2px 8px; border: 1px solid var(--border); border-radius: 4px; background: var(--bg-card);
  color: var(--muted-2); cursor: pointer; transition: all .12s; text-transform: none; vertical-align: middle;
}
.share-btn:hover { border-color: var(--accent); color: var(--accent-deep); }

/* toast */
#toast {
  position: fixed; left: 50%; bottom: 28px; transform: translateX(-50%) translateY(10px);
  background: var(--ink); color: var(--bg-card); font-family: var(--mono); font-size: 11.5px;
  padding: 8px 16px; border-radius: 6px; box-shadow: var(--shadow); z-index: 300;
  opacity: 0; pointer-events: none; transition: opacity .18s, transform .18s;
}
[data-theme="dark"] #toast { background: var(--accent); color: #0b1220; }
#toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

/* source hovercard */
#hovercard {
  position: fixed; z-index: 250; max-width: 340px; pointer-events: none;
  background: var(--bg-card); border: 1px solid var(--border); border-radius: 9px;
  box-shadow: 0 8px 28px rgba(0,0,0,0.18); padding: 10px 13px;
  opacity: 0; transition: opacity .12s; font-family: var(--sans);
}
#hovercard.show { opacity: 1; }
#hovercard .hc-title { font-size: 13px; font-weight: 500; color: var(--ink); line-height: 1.35; margin-bottom: 4px; }
#hovercard .hc-authors { font-size: 11.5px; color: var(--muted); line-height: 1.4; }
#hovercard .hc-line { font-size: 11px; color: var(--muted-2); margin-top: 3px; }
#hovercard .hc-id { font-family: var(--mono); font-size: 9.5px; color: var(--muted-4); margin-top: 5px; letter-spacing: 0.2px; }
/* compact acronym-definition variant */
#hovercard.hc-def { max-width: 260px; padding: 8px 11px; }
#hovercard .hc-term { font-family: var(--mono); font-size: 11px; font-weight: 600; color: var(--accent); letter-spacing: 0.3px; }
#hovercard .hc-mean { font-size: 12.5px; color: var(--ink); line-height: 1.4; margin-top: 2px; }
.prose p { margin: 12px 0; }
.prose ul, .prose ol { margin: 12px 0 12px 24px; }
.prose li { margin: 5px 0; }
.prose li::marker { color: var(--muted-3); }
.prose strong { font-weight: 600; color: var(--ink); }
.prose em { font-style: italic; }
.prose hr { border: none; border-top: 1px solid var(--border); margin: 28px 0; }

.prose a { border-bottom: 1px solid color-mix(in srgb, var(--accent) 35%, transparent); }
.prose a:hover { border-bottom-color: var(--accent); }

/* inline code & blocks */
.prose code {
  font-family: var(--mono); font-size: 0.86em;
  background: var(--bg-code); border: 1px solid var(--border-soft);
  padding: 1px 5px; border-radius: 4px; color: var(--ink);
}
.prose pre {
  background: var(--bg-code); border: 1px solid var(--border);
  border-radius: 8px; padding: 14px 16px; overflow-x: auto; margin: 16px 0;
  font-size: 12.8px; line-height: 1.55;
}
.prose pre code { background: none; border: none; padding: 0; font-size: inherit; color: var(--ink-2); }
/* active-search term highlighting inside the article (cleared with the search) —
   a filled rectangle so hits stand out against prose, headings, and inline code */
mark.search-hl {
  background: var(--hl-bg); color: var(--hl-ink);
  font-weight: 600; border-radius: 3px;
  padding: 0.5px 3.5px; margin: 0 0.5px;
  box-shadow: 0 0 0 1px var(--hl-bg);
  -webkit-box-decoration-break: clone; box-decoration-break: clone;
}

/* blockquote */
.prose blockquote {
  margin: 16px 0; padding: 8px 16px; border-left: 3px solid var(--accent);
  background: var(--bg-soft); color: var(--muted); border-radius: 0 6px 6px 0;
}
.prose blockquote p { margin: 6px 0; }

/* tables */
.prose table {
  border-collapse: collapse; margin: 18px 0; font-size: 13px; width: 100%;
  display: block; overflow-x: auto; box-shadow: var(--shadow); border-radius: 8px;
}
.prose thead { background: var(--bg-soft); }
.prose th {
  text-align: left; font-family: var(--mono); font-weight: 600; font-size: 11px;
  letter-spacing: 0.4px; text-transform: uppercase; color: var(--muted);
  padding: 9px 13px; border-bottom: 2px solid var(--border); white-space: nowrap;
}
.prose td { padding: 8px 13px; border-bottom: 1px solid var(--border-soft); color: var(--ink-3); vertical-align: top; }
.prose tbody tr:last-child td { border-bottom: none; }
.prose tbody tr:hover { background: var(--bg-soft); }
.prose td code { white-space: nowrap; }

/* KaTeX */
.prose .katex { font-size: 1.04em; }
.prose .katex-display {
  margin: 18px 0; padding: 6px 4px; overflow-x: auto; overflow-y: hidden;
}
.prose .katex-display > .katex { white-space: nowrap; }
.katex-error { color: var(--danger) !important; font-family: var(--mono); font-size: 0.9em; }

/* ── Citation chips (the signature feature) ────────────── */
.cite {
  display: inline-block; font-family: var(--mono); font-size: 0.74em;
  font-weight: 500; letter-spacing: 0.2px; line-height: 1.3;
  padding: 0.5px 5px; margin: 0 1px; border-radius: 4px; vertical-align: 0.12em;
  background: var(--accent-soft); color: var(--accent-deep);
  border: 1px solid transparent; white-space: nowrap; cursor: pointer;
  transition: background .12s, border-color .12s; border-bottom: none;
}
.cite:hover { background: var(--accent-hover-row); color: var(--accent-deep); border-color: var(--accent); }
.cite.unresolved { background: var(--bg-soft); color: var(--muted-2); }
.cite.unresolved:hover { border-color: var(--muted-4); color: var(--ink-3); }
.cite .cite-mark { opacity: 0.65; margin-right: 2px; }

/* ── Right aside (metadata + TOC) ──────────────────────── */
.aside {
  position: sticky; top: 53px; align-self: start;
  height: calc(100vh - 53px); overflow-y: auto;
  padding: 26px 20px 60px 4px; display: none;
}
@media (min-width: 1180px) { .layout.has-aside .aside { display: block; } }

.panel {
  background: var(--bg-card); border: 1px solid var(--border); border-radius: 10px;
  padding: 14px 15px; margin-bottom: 16px; box-shadow: var(--shadow);
}
.panel-title {
  font-family: var(--mono); font-size: 9.5px; font-weight: 600; text-transform: uppercase;
  letter-spacing: 1.3px; color: var(--muted-3); margin-bottom: 10px;
}
.meta-row { display: flex; gap: 8px; font-size: 12px; margin: 6px 0; line-height: 1.5; }
.meta-row .k {
  flex: 0 0 78px; color: var(--muted-3); font-family: var(--mono); font-size: 10.5px;
  text-transform: uppercase; letter-spacing: 0.3px; padding-top: 1px;
}
.meta-row .v { flex: 1; color: var(--ink-3); min-width: 0; word-break: break-word; }
.meta-row .v a { word-break: break-all; }

.chips { display: flex; flex-wrap: wrap; gap: 5px; margin-top: 4px; }
.chip {
  display: inline-flex; align-items: center; font-family: var(--mono); font-size: 10.5px;
  padding: 2px 7px; border-radius: 5px; background: var(--bg-soft);
  border: 1px solid var(--border-soft); color: var(--muted); cursor: pointer; transition: all .12s;
}
.chip:hover { border-color: var(--accent); color: var(--accent-deep); background: var(--accent-soft); }
.chip.ext::after { content: "↗"; margin-left: 4px; opacity: 0.5; font-size: 0.9em; }
.chip.res { background: var(--accent-soft); color: var(--accent-deep); border-color: transparent; }

.toc { line-height: 1.4; }
.toc a {
  display: block; font-size: 12px; color: var(--muted-2); padding: 3px 0 3px 10px;
  border-left: 2px solid var(--border-soft); transition: all .12s;
}
.toc a:hover { color: var(--ink); border-left-color: var(--muted-3); }
.toc a.h3 { padding-left: 22px; font-size: 11.5px; }
.toc a.active { color: var(--accent-deep); border-left-color: var(--accent); font-weight: 500; }

.oq-list { list-style: none; margin: 0 !important; }
.oq-list li {
  font-size: 12px; color: var(--ink-3); padding: 8px 0; border-bottom: 1px solid var(--border-soft);
  line-height: 1.5;
}
.oq-list li:last-child { border-bottom: none; }
.oq-list li::before { content: "?"; color: var(--accent); font-family: var(--mono); font-weight: 600; margin-right: 7px; }

/* ── Home view ─────────────────────────────────────────── */
.home { padding: 40px 38px 80px; max-width: 780px; margin: 0 auto; }
@media (max-width: 760px) { .home { padding: 28px 18px 60px; } }

/* ── Hero + foreword (the "book intro") ────────────────── */
.hero { margin-bottom: 22px; }
.hero h1 {
  font-family: var(--mono); font-weight: 600; font-size: 38px; line-height: 1.1;
  letter-spacing: -0.5px; color: var(--ink); margin-bottom: 14px;
}
.hero h1 .dot { color: var(--accent); }
.hero-tag { font-size: 17px; line-height: 1.5; color: var(--muted); font-weight: 300; max-width: 640px; }

.foreword { margin: 26px 0 24px; }
.foreword p {
  font-size: 15.5px; line-height: 1.72; color: var(--ink-2); font-weight: 300;
  margin: 0 0 14px;
}
.foreword p:last-child { margin-bottom: 0; }
.foreword em { font-style: italic; color: var(--ink); }
.foreword strong { font-weight: 600; color: var(--ink); }
.foreword abbr, .prose abbr { text-decoration: none; border-bottom: 1px dotted var(--muted-4); cursor: help; font-weight: 500; color: var(--ink); }
/* acronym hovers inside article prose — subtle (there can be many); inherit color, faint underline */
.prose abbr.ac { font-weight: inherit; color: inherit; border-bottom: 1px dotted var(--muted-5); }
/* in-article §N section references */
.prose a.secref {
  color: var(--accent); border-bottom: 1px dotted color-mix(in srgb, var(--accent) 45%, transparent);
  font-variant-numeric: tabular-nums; white-space: nowrap;
}
.prose a.secref:hover { border-bottom-style: solid; }
/* inline `code` that resolves to a topic → a link, styled like a code chip in accent */
.prose a.topicref { text-decoration: none; border: none; }
.prose a.topicref code {
  color: var(--accent-deep); background: var(--accent-soft); border-color: transparent;
  cursor: pointer; transition: box-shadow .12s;
}
.prose a.topicref:hover code { box-shadow: inset 0 -1px 0 var(--accent); }
.prose a.topicref::after { content: " ↗"; font-size: 0.8em; color: var(--accent); opacity: 0.55; }

/* slim stats line — present but subordinate to the narrative */
.home-stats {
  display: flex; flex-wrap: wrap; align-items: center; gap: 4px 0;
  font-family: var(--mono); font-size: 12px; color: var(--muted-2);
  padding: 14px 0; border-top: 1px solid var(--border); border-bottom: 1px solid var(--border);
  margin-bottom: 8px; font-variant-numeric: tabular-nums;
}
.home-stats a, .home-stats span { color: var(--muted); text-decoration: none; }
.home-stats a:hover { color: var(--accent); }
.home-stats b { color: var(--accent); font-weight: 600; }
.home-stats .sep { color: var(--muted-4); margin: 0 12px; }

.section-head {
  font-family: var(--mono); font-size: 12px; font-weight: 600; text-transform: uppercase;
  letter-spacing: 1.5px; color: var(--ink-3); margin: 34px 0 6px;
  display: flex; align-items: center; gap: 10px;
}
.section-head::after { content: ""; flex: 1; height: 1px; background: var(--border); }
.section-lead { font-size: 13px; color: var(--muted-2); margin: 0 0 14px; line-height: 1.5; }

/* Start-here featured cards */
.feature-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); gap: 12px; }
.feature-card {
  background: var(--bg-card); border: 1px solid var(--border); border-radius: 10px;
  padding: 15px 16px; cursor: pointer; transition: all .15s; box-shadow: var(--shadow);
  display: flex; flex-direction: column; gap: 6px;
}
.feature-card:hover { border-color: var(--accent); transform: translateY(-1px); }
.feature-card .fc-cat { font-family: var(--mono); font-size: 9.5px; text-transform: uppercase; letter-spacing: 0.8px; color: var(--accent); }
.feature-card .fc-title { font-family: var(--mono); font-size: 14px; font-weight: 600; color: var(--ink); line-height: 1.3; }
.feature-card .fc-scope { font-size: 12px; color: var(--muted-2); line-height: 1.45; }

/* latest updates feed */
.updates { border: 1px solid var(--border); border-radius: 10px; background: var(--bg-card); box-shadow: var(--shadow); overflow: hidden; }
.upd { display: flex; align-items: baseline; gap: 10px; padding: 9px 14px; border-bottom: 1px solid var(--border-soft); text-decoration: none; transition: background .12s; }
.upd:last-child { border-bottom: none; }
.upd:hover { background: var(--bg-soft); }
.upd-kind {
  flex: 0 0 auto; font-family: var(--mono); font-size: 9px; font-weight: 600; text-transform: uppercase;
  letter-spacing: 0.5px; padding: 2px 6px; border-radius: 4px; width: 48px; text-align: center; align-self: center;
  background: var(--bg-soft); color: var(--muted-2); border: 1px solid var(--border-soft);
}
.upd-kind.k-topic { background: var(--accent-soft); color: var(--accent-deep); border-color: transparent; }   /* new topic node */
.upd-kind.k-edit { background: var(--bg-soft); color: var(--muted); border-color: var(--border); }             /* modified */
.upd-kind.k-source { background: none; color: var(--muted-3); }                                                /* new source */
.upd-title { flex: 1; min-width: 0; font-size: 13px; color: var(--ink-2); line-height: 1.4;
  overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.upd:hover .upd-title { color: var(--accent-deep); }
.upd-meta { flex: 0 0 auto; font-family: var(--mono); font-size: 10px; color: var(--muted-4); display: flex; gap: 8px; align-items: baseline; }
.upd-time { color: var(--muted-3); }
@media (max-width: 640px) { .upd-title { white-space: normal; } .upd-meta { display: none; } }

.built-open {
  margin-top: 36px; padding-top: 16px; border-top: 1px solid var(--border);
  font-size: 12.5px; color: var(--muted-2); line-height: 1.6;
}
.built-open a { color: var(--muted); text-decoration: none; border-bottom: 1px solid var(--border); }
.built-open a:hover { color: var(--accent); border-bottom-color: var(--accent); }

.cat-block { margin-bottom: 22px; }
.cat-name {
  font-family: var(--mono); font-size: 11px; text-transform: uppercase; letter-spacing: 1px;
  color: var(--muted-2); margin-bottom: 8px;
}
.card-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 12px; }
.card {
  background: var(--bg-card); border: 1px solid var(--border); border-radius: 10px;
  padding: 15px 16px; cursor: pointer; transition: all .15s; box-shadow: var(--shadow);
  display: flex; flex-direction: column; gap: 8px; min-height: 84px;
}
.card:hover { border-color: var(--accent); transform: translateY(-1px); }
.card .c-title { font-family: var(--mono); font-size: 13.5px; font-weight: 500; color: var(--ink); line-height: 1.35; }
.card .c-foot { display: flex; align-items: center; justify-content: space-between; gap: 8px; margin-top: auto; }
.card .c-id { font-family: var(--mono); font-size: 10px; color: var(--muted-4); letter-spacing: 0.2px; }

/* source rows on home */
.src-row {
  display: flex; align-items: baseline; gap: 12px; padding: 10px 12px;
  border-bottom: 1px solid var(--border-soft); cursor: pointer; transition: background .12s; border-radius: 6px;
}
.src-row:hover { background: var(--bg-soft); }
/* title leads; the id is a de-emphasized reference tag at the end */
.src-row .sr-title { font-size: 13.5px; color: var(--ink-2); flex: 1; min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.src-row .sr-year { font-family: var(--mono); font-size: 11px; color: var(--muted-4); white-space: nowrap; }
.src-row .sr-id { font-family: var(--mono); font-size: 10.5px; color: var(--muted-4); white-space: nowrap; flex: 0 0 auto; }

/* ── Sources browser (#/sources, main area) ────────────── */
.src-browser { max-width: 920px; }
.src-tools { display: flex; flex-wrap: wrap; gap: 10px; align-items: center; margin: 4px 0 6px; }
.src-search-wrap { position: relative; flex: 1 1 280px; }
.src-search-wrap::before { content: "⌕"; position: absolute; left: 11px; top: 50%; transform: translateY(-50%); color: var(--muted-3); font-size: 15px; }
.src-search { width: 100%; font-family: var(--sans); font-size: 13.5px; padding: 9px 12px 9px 32px;
  border: 1px solid var(--border); border-radius: 7px; background: var(--bg-card); color: var(--ink); }
.src-search:focus { outline: none; border-color: var(--accent); }
.src-browser .sort-switch { margin: 0; flex: 0 0 auto; width: auto; }
.src-browser .ns-chips { margin: 0 0 10px; }
.src-browser .cov-chips { margin-top: 2px; }
.cov-note { font-size: 12px; color: var(--muted-2); margin: 0 2px 12px; }
.cov-note b { color: var(--accent); font-weight: 600; font-variant-numeric: tabular-nums; }
.src-browser .list-meta { padding: 2px 4px 8px; }

/* ── States ───────────────────────────────────────────── */
.loading, .error-box {
  padding: 40px; text-align: center; color: var(--muted-2); font-family: var(--mono); font-size: 13px;
}
.error-box { color: var(--danger); }
.spinner {
  width: 22px; height: 22px; border: 2px solid var(--border); border-top-color: var(--accent);
  border-radius: 50%; animation: spin .7s linear infinite; margin: 0 auto 14px;
}
@keyframes spin { to { transform: rotate(360deg); } }

.skel { background: linear-gradient(90deg, var(--bg-soft) 25%, var(--border-soft) 50%, var(--bg-soft) 75%);
  background-size: 200% 100%; animation: sh 1.3s infinite; border-radius: 5px; }
@keyframes sh { to { background-position: -200% 0; } }

/* footer */
.foot { margin-top: 40px; padding-top: 18px; border-top: 1px solid var(--border);
  font-family: var(--mono); font-size: 11px; color: var(--muted-3); display: flex; gap: 16px; flex-wrap: wrap; }
.foot a { color: var(--muted-2); }

/* ── Responsive sidebar ────────────────────────────────── */
@media (max-width: 900px) {
  .layout { grid-template-columns: 1fr; }
  .menu-toggle { display: inline-flex; }
  .sidebar {
    position: fixed; left: 0; top: 0; bottom: 0; width: 290px; z-index: 100;
    height: 100vh; transform: translateX(-100%); transition: transform .2s;
    box-shadow: var(--shadow); padding-top: 60px;
  }
  body.nav-open .sidebar { transform: translateX(0); }
  .nav-scrim { display: none; position: fixed; inset: 0; background: rgba(0,0,0,0.4); z-index: 99; }
  body.nav-open .nav-scrim { display: block; }
}
@media (min-width: 901px) { .nav-scrim { display: none !important; } }

/* ── Collapsible taxonomy tree (topics sidebar) ────────── */
.nav-cat { margin-bottom: 10px; }
.nav-cat-head {
  display: flex; align-items: baseline; gap: 7px; width: 100%; padding: 5px 6px; cursor: pointer;
  border-radius: 5px; background: none; border: none; text-align: left;
  font-family: var(--sans); font-size: 13.5px; font-weight: 600; letter-spacing: 0;
  color: var(--ink); transition: background .12s;
}
.nav-cat-head:hover { background: var(--bg-soft); }
/* fold indicator lives at the far right; points down when open, left when collapsed */
.nav-cat-head .caret { font-size: 18px; line-height: 1; color: var(--muted-2); transition: transform .15s, color .12s; width: 16px; text-align: center; align-self: center; flex: none; order: 3; }
.nav-cat-head:hover .caret { color: var(--ink-3); }
.nav-cat-head.collapsed .caret { transform: rotate(-90deg); }
.nav-cat-head .cat-label { flex: 1; min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; order: 1; }
.nav-cat-head .cat-count { order: 2; }
.nav-cat-head .cat-count {
  font-family: var(--mono); font-size: 10px; font-weight: 500; color: var(--muted-4); font-variant-numeric: tabular-nums;
}
.nav-cat-head .cat-count .w { color: var(--accent); font-weight: 600; }
/* items sit visually under their (bolder) heading */
.nav-cat-body { padding-left: 16px; margin-top: 1px; border-left: 1px solid var(--border-soft); margin-left: 9px; }
.nav-cat-body.collapsed { display: none; }
.nav-cat-body .nav-item { font-size: 12.5px; }
/* deeper sub-categories: slightly smaller/muted headers, and less margin so nesting stays compact */
.nav-cat-head.lvl-2 { font-size: 12.5px; }
.nav-cat-head.lvl-3, .nav-cat-head.lvl-4 { font-size: 12px; color: var(--ink-3); }
.nav-cat-body .nav-cat { margin-bottom: 2px; }
/* a node that is itself an article AND has sub-articles: the header label links to
   its own article, and only the caret toggles the sub-articles */
.nav-cat-head.has-page { cursor: default; }
.nav-cat-head .caret { cursor: pointer; }
.nav-cat-head .cat-link { color: inherit; text-decoration: none; cursor: pointer; }
.nav-cat-head .cat-link:hover, .nav-cat-head .cat-link.active { color: var(--accent); }
/* an article-with-children reads like a normal article entry (not a bold category
   header) — the right-side caret is the only cue that it also unfolds */
/* an article-with-subpages should be visually identical to a leaf .nav-item — same
   weight, colour, and left indent — differing ONLY by the fold caret on the right */
.nav-cat-head.has-page { font-weight: 300; font-size: 12.5px; padding: 5px 9px; border-left: 2px solid transparent; }
.nav-cat-head.has-page .cat-link { color: var(--ink-3); font-weight: 300; }
.nav-cat-head.has-page:hover .cat-link { color: var(--ink); }
.nav-cat-head.has-page:has(.cat-link.active) { background: var(--accent-soft); border-left-color: var(--accent); }
.nav-cat-head.has-page .cat-link.active { color: var(--accent-deep); font-weight: 500; }

/* ── Namespace filter chips (sources sidebar) ──────────── */
.ns-chips { display: flex; flex-wrap: wrap; gap: 5px; margin-bottom: 10px; }
.ns-chip {
  font-family: var(--mono); font-size: 10px; padding: 3px 9px; border-radius: 20px;
  border: 1px solid var(--border); background: var(--bg-card); color: var(--muted-2); cursor: pointer; transition: all .12s;
}
.ns-chip:hover { border-color: var(--muted-3); color: var(--ink); }
.ns-chip.active { background: var(--ink); color: var(--bg-card); border-color: var(--ink); }
[data-theme="dark"] .ns-chip.active { background: var(--accent); border-color: var(--accent); color: #0b1220; }
.ns-chip .c { opacity: 0.6; }
.list-meta {
  font-family: var(--mono); font-size: 10px; color: var(--muted-4); letter-spacing: 0.2px;
  padding: 8px 9px 4px; display: flex; justify-content: space-between; align-items: baseline; gap: 8px;
}
.list-meta .hint { color: var(--muted-5); }

/* ── Home: the Contents tree (rollup words + references) ── */
.tree { border: 1px solid var(--border); border-radius: 10px; background: var(--bg-card); box-shadow: var(--shadow); overflow: hidden; }
.tree-root {
  font-family: var(--mono); font-size: 12.5px; color: var(--muted); padding: 12px 16px;
  border-bottom: 1px solid var(--border); background: var(--bg-soft); font-variant-numeric: tabular-nums;
}
.tree-root b { color: var(--accent); font-weight: 600; }
.tree-cat { border-bottom: 1px solid var(--border-soft); }
.tree-cat:last-child { border-bottom: none; }
.tree-cat-head {
  display: flex; align-items: baseline; gap: 9px; width: 100%; text-align: left; cursor: pointer;
  background: none; border: none; padding: 10px 16px; transition: background .12s;
}
.tree-cat-head:hover { background: var(--bg-soft); }
/* name fills the row so the fold caret sits at the far right */
.tree-cat-head .tc-name-wrap { flex: 1; min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.tree-cat-head .caret { font-size: 11px; color: var(--muted-2); transition: transform .15s, color .12s; width: 12px; text-align: center; align-self: center; flex: none; margin-left: 4px; }
.tree-cat-head:hover .caret { color: var(--ink-3); }
.tree-cat-head.collapsed .caret { transform: rotate(-90deg); }
.tree-cat-head .tc-name { font-family: var(--mono); font-size: 13.5px; font-weight: 600; color: var(--ink); }
.tree-cat-head .tc-frac { font-family: var(--mono); font-size: 10.5px; color: var(--muted-4); font-variant-numeric: tabular-nums; }
.tree-cat-head .tc-frac .w { color: var(--accent); }
.t-count {
  margin-left: auto; font-family: var(--mono); font-size: 11px; color: var(--muted-2);
  font-variant-numeric: tabular-nums; white-space: nowrap; padding-left: 12px;
}
.t-count b { color: var(--ink-3); font-weight: 600; }
.tree-cat-body { padding: 2px 16px 12px 30px; }
.tree-cat-body.collapsed { display: none; }
/* nested sub-categories in the Contents tree: no divider, smaller header, tighter indent */
.tree-cat-body .tree-cat { border-bottom: none; }
.tree-cat-body .tree-cat-head { padding: 6px 8px; }
.tree-cat-head.lvl-2 .tc-name { font-size: 12.5px; }
.tree-cat-head.lvl-3 .tc-name, .tree-cat-head.lvl-4 .tc-name { font-size: 12px; color: var(--ink-2); }
/* article-with-children: header name links to its own article, caret toggles children */
.tree-cat-head.has-page { cursor: default; }
.tree-cat-head .caret { cursor: pointer; }
.tree-cat-head a.tc-name { text-decoration: none; cursor: pointer; }
.tree-cat-head a.tc-name:hover { color: var(--accent); text-decoration: underline; }
/* article-with-children reads exactly like a leaf article row (sans, not bold mono) */
.tree-cat-head.has-page a.tc-name { font-family: var(--sans); font-weight: 300; font-size: 13px; color: var(--ink-2); }
.tree-cat-head.has-page a.tc-name:hover { color: var(--accent-deep); }
/* ...and carries the same green dot as its leaf-article siblings */
.tree-cat-head .tl-dot { display: inline-block; width: 6px; height: 6px; border-radius: 50%; background: var(--good); margin-right: 9px; vertical-align: middle; }
.tree-cat-body .tree-cat-body { padding: 2px 8px 8px 22px; }
/* ── file-tree connectors: link subtopics to their parent ── */
.tree-cat-body { position: relative; }
.tree-cat-body > .tree-leaf, .tree-cat-body > .tree-cat { position: relative; }
/* vertical spine — one segment per child; they stack into a continuous line */
.tree-cat-body > .tree-leaf::before, .tree-cat-body > .tree-cat::before {
  content: ""; position: absolute; left: -13px; top: 0; bottom: 0; border-left: 1px solid var(--border);
}
/* last child: stop the spine at its own elbow (draws the └ corner) */
.tree-cat-body > .tree-leaf:last-child::before, .tree-cat-body > .tree-cat:last-child::before {
  bottom: auto; height: 13px;
}
/* horizontal elbow reaching from the spine to the row */
.tree-cat-body > .tree-leaf::after, .tree-cat-body > .tree-cat > .tree-cat-head::after {
  content: ""; position: absolute; left: -13px; top: 13px; width: 11px; border-top: 1px solid var(--border);
}
.tree-cat-body > .tree-cat > .tree-cat-head { position: relative; }
.tree-desc { font-size: 12px; color: var(--muted-2); line-height: 1.5; margin: 0 0 8px; max-width: 640px; }
.tree-leaf {
  display: flex; align-items: baseline; gap: 8px; padding: 4px 6px; border-radius: 5px;
  font-size: 13px; color: var(--ink-2); text-decoration: none; border-bottom: none;
}
a.tree-leaf { cursor: pointer; }
a.tree-leaf:hover { background: var(--bg-soft); color: var(--accent-deep); }
.tree-leaf .tl-dot { width: 6px; height: 6px; border-radius: 50%; background: var(--good); flex: 0 0 auto; align-self: center; }
.tree-leaf .tl-name { min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.tree-leaf.planned { color: var(--muted-4); cursor: default; }
.tree-leaf.planned[title] { cursor: help; }
.tree-leaf .tl-dot.planned { background: none; border: 1px solid var(--muted-5); }
.tree-leaf .tl-tag { margin-left: auto; font-family: var(--mono); font-size: 9.5px; text-transform: uppercase; letter-spacing: 0.4px; color: var(--muted-5); }
/* inline legend dots in the section lead */
.section-lead .tl-dot { display: inline-block; width: 7px; height: 7px; border-radius: 50%; background: var(--good); vertical-align: middle; margin: 0 2px; }
.section-lead .tl-dot.planned { background: none; border: 1px solid var(--muted-5); }

/* ── Sources sort switch ───────────────────────────────── */
.sort-switch { display: flex; gap: 0; margin-bottom: 8px; border: 1px solid var(--border); border-radius: 6px; overflow: hidden; }
.sort-opt {
  flex: 1; font-family: var(--mono); font-size: 9.5px; letter-spacing: 0.3px; text-transform: uppercase;
  padding: 5px 4px; border: none; background: var(--bg-card); color: var(--muted-2); cursor: pointer;
  border-right: 1px solid var(--border); transition: all .12s;
}
.sort-opt:last-child { border-right: none; }
.sort-opt:hover { color: var(--ink); background: var(--bg-soft); }
.sort-opt.active { background: var(--accent-soft); color: var(--accent-deep); font-weight: 600; }

/* ── Cited-by panel (source page) ──────────────────────── */
.cite-loading { font-size: 11.5px; color: var(--muted-3); font-style: italic; padding: 2px 0; }
.citedby-row {
  display: flex; align-items: baseline; justify-content: space-between; gap: 8px;
  padding: 6px 0; border-bottom: 1px solid var(--border-soft); cursor: pointer;
}
.citedby-row:last-child { border-bottom: none; }
.citedby-row .cb-title { font-size: 12.5px; color: var(--ink-2); line-height: 1.35; border-bottom: none; }
.citedby-row:hover .cb-title { color: var(--accent-deep); }
.citedby-row .cb-cat { font-family: var(--mono); font-size: 9px; color: var(--muted-4); text-transform: uppercase; letter-spacing: 0.3px; white-space: nowrap; }

/* ============================================================
   BOOK VIEW (#/book) — the whole wiki as one printable document
   ============================================================ */
.book-cta {
  display: flex; align-items: center; gap: 4px; margin: 10px 0 2px; padding: 12px 16px;
  border: 1px solid var(--border); border-radius: 10px; background: var(--bg-card);
  font-size: 13.5px; color: var(--ink-2); text-decoration: none; transition: all .15s; box-shadow: var(--shadow);
}
.book-cta:hover { border-color: var(--accent); color: var(--accent-deep); transform: translateY(-1px); }
.book-cta .arr { margin-left: auto; color: var(--accent); font-weight: 600; }

body.book-mode .sidebar, body.book-mode .aside { display: none !important; }
body.book-mode .layout { grid-template-columns: 1fr; }
body.book-mode .main { padding: 0; }

.book-toolbar {
  position: sticky; top: 53px; z-index: 40; display: flex; align-items: center; gap: 8px;
  padding: 10px 22px; background: color-mix(in srgb, var(--bg) 90%, transparent);
  backdrop-filter: blur(8px); border-bottom: 1px solid var(--border);
}
.book-toolbar .spacer { flex: 1; }
.book-toolbar .bk-hint { font-size: 11.5px; color: var(--muted-3); }
@media (max-width: 640px) { .book-toolbar .bk-hint { display: none; } }

.book { max-width: 760px; margin: 0 auto; padding: 40px 40px 90px; color: var(--ink-2); }
.book .dot { color: var(--accent); }

/* title page */
.book-titlepage { text-align: center; padding: 56px 0 72px; border-bottom: 1px solid var(--border); margin-bottom: 44px; }
.bk-tp-kicker { font-family: var(--mono); font-size: 11px; text-transform: uppercase; letter-spacing: 1.6px; color: var(--accent); margin-bottom: 22px; }
.bk-tp-title { font-family: var(--mono); font-weight: 600; font-size: 42px; line-height: 1.08; color: var(--ink); margin-bottom: 22px; letter-spacing: -0.5px; }
.bk-tp-sub { font-size: 15px; line-height: 1.62; color: var(--muted); max-width: 540px; margin: 0 auto 34px; font-weight: 300; }
.bk-tp-meta { font-family: var(--mono); font-size: 12px; color: var(--muted-2); line-height: 2; }
.bk-tp-meta b { color: var(--accent); }
.bk-tp-src { color: var(--muted-4); font-size: 11px; }

/* contents */
.book-toc { margin-bottom: 20px; }
.bk-h { font-family: var(--mono); font-size: 24px; font-weight: 600; color: var(--ink); margin-bottom: 18px; }
.bk-toc-part { margin: 13px 0 3px; }
.bk-toc-part a { font-family: var(--mono); font-weight: 600; font-size: 14px; color: var(--ink); cursor: pointer; text-decoration: none; }
.bk-toc-num { color: var(--accent); margin-right: 8px; }
.bk-toc-art { padding-left: 28px; margin: 2px 0; }
.bk-toc-art a { font-size: 13px; color: var(--muted); cursor: pointer; text-decoration: none; }
.bk-toc-art a:hover, .bk-toc-part a:hover { color: var(--accent); }

/* parts */
.book-part { padding: 30px 0 10px; border-top: 2px solid var(--ink); margin-top: 44px; }
.bk-part-kicker { font-family: var(--mono); font-size: 11px; text-transform: uppercase; letter-spacing: 2px; color: var(--accent); }
.bk-part-title { font-family: var(--mono); font-size: 30px; font-weight: 600; color: var(--ink); margin: 8px 0 12px; letter-spacing: -0.3px; }
.bk-part-desc { font-size: 14px; color: var(--muted); line-height: 1.6; max-width: 560px; }

/* articles */
.book-article { padding: 30px 0; border-top: 1px solid var(--border); }
.bk-art-cat { font-family: var(--mono); font-size: 10px; text-transform: uppercase; letter-spacing: 1px; color: var(--muted-3); }
.bk-art-title { font-family: var(--mono); font-size: 22px; font-weight: 600; color: var(--ink); margin: 4px 0 14px; letter-spacing: -0.2px; }
.book-prose h1 { display: block; font-size: 20px; }

/* appendix + colophon */
.book-appendix { padding: 30px 0; border-top: 2px solid var(--ink); margin-top: 44px; }
.bk-appendix-lead { font-size: 13px; color: var(--muted); margin-bottom: 16px; max-width: 560px; }
.bk-refs { display: block; }
.bk-ref { display: grid; grid-template-columns: 150px 1fr; gap: 2px 12px; padding: 7px 0; border-bottom: 1px solid var(--border-soft); font-size: 12px; }
.bk-ref-id { font-family: var(--mono); color: var(--accent); }
.bk-ref-title { color: var(--ink-3); }
.bk-ref-url { grid-column: 2; font-family: var(--mono); font-size: 10.5px; color: var(--muted-4); }
.book-colophon { margin-top: 44px; padding-top: 20px; border-top: 1px solid var(--border); font-size: 11px; color: var(--muted-3); text-align: center; line-height: 1.6; }

/* ── Print (browser "Save as PDF") ─────────────────────── */
@media print {
  .topbar, .sidebar, .aside, .nav-scrim, .book-toolbar, #hovercard, #toast, .foot, .menu-toggle { display: none !important; }
  html, body { background: #fff; color: #000; }
  .layout, .main, body.book-mode .main { display: block; padding: 0; margin: 0; }
  .book { max-width: none; margin: 0; padding: 0; color: #111; font-size: 10.5pt; }
  @page { size: A4; margin: 18mm 16mm; }
  .book-titlepage { break-after: page; border: none; padding: 30mm 0; margin: 0; }
  .book-toc { break-after: page; }
  .book-part { break-before: page; border-top: none; margin: 0; padding: 0; }
  .book-appendix { break-before: page; border-top: none; margin: 0; }
  .book-article { break-before: page; border-top: none; padding: 0; margin: 0; }   /* each topic starts a fresh page */
  .bk-art-title, .bk-part-title, .prose h2, .prose h3, .bk-art-cat { break-after: avoid; }
  .prose table, .prose pre, .prose blockquote, .katex-display, .bk-ref, .prose li { break-inside: avoid; }
  .book-prose { line-height: 1.5; }
  .book-colophon { break-before: avoid; }
  .prose a, .book a { color: #111; text-decoration: none; }
  .cite { background: none !important; border: none !important; color: #444 !important; font-size: 0.78em; padding: 0 1px; }
  .cite .cite-mark { display: none; }
  a.secref { color: #111; border: none; }
  .prose abbr.ac { border: none; }
  /* single-article print: show collapsed disclosures + drop their chrome */
  .disclosure { border: none; }
  .disclosure > summary { padding-left: 0; }
  .disclosure > summary::after { display: none; }
  .disclosure > *:not(summary) { display: block !important; }
  .page-links { display: none; }
  .prose .fig { break-inside: avoid; }
}