/* ---------- tokens ---------- */
:root {
  color-scheme: light;
  --bg: #ffffff;
  --bg-2: #f8f9fa;
  --ink: #202122;
  --ink-2: #54595d;
  --muted: #72777d;
  --hair: #eaecf0;
  --border: #c8ccd1;
  --link: #3366cc;
  --accent: #3366cc;
  --rel-gen: #2a78d6;
  --rel-der: #eb6834;
  --rel-app: #1baf7a;
  --map-node: #72777d;
  --map-edge: rgba(32, 33, 34, 0.07);
  --map-land: rgba(32, 33, 34, 0.035);
  --map-land-on: rgba(51, 102, 204, 0.09);
  --serif: "Linux Libertine", "Libertinus Serif", Georgia, "Times New Roman", serif;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --top: 52px;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --bg: #101214;
    --bg-2: #181b1e;
    --ink: #eaecf0;
    --ink-2: #c8ccd1;
    --muted: #a2a9b1;
    --hair: #272b30;
    --border: #3d434a;
    --link: #88a3e8;
    --accent: #88a3e8;
    --rel-gen: #3987e5;
    --rel-der: #d95926;
    --rel-app: #199e70;
    --map-node: #a2a9b1;
    --map-edge: rgba(234, 236, 240, 0.08);
    --map-land: rgba(234, 236, 240, 0.04);
    --map-land-on: rgba(136, 163, 232, 0.12);
  }
}
:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #101214;
  --bg-2: #181b1e;
  --ink: #eaecf0;
  --ink-2: #c8ccd1;
  --muted: #a2a9b1;
  --hair: #272b30;
  --border: #3d434a;
  --link: #88a3e8;
  --accent: #88a3e8;
  --rel-gen: #3987e5;
  --rel-der: #d95926;
  --rel-app: #199e70;
  --map-node: #a2a9b1;
  --map-edge: rgba(234, 236, 240, 0.08);
  --map-land: rgba(234, 236, 240, 0.04);
  --map-land-on: rgba(136, 163, 232, 0.12);
}

/* ---------- base ---------- */
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.6 var(--sans);
}
a { color: var(--link); text-decoration: none; }
a:hover { text-decoration: underline; }
h1, h2 { font-family: var(--serif); font-weight: normal; line-height: 1.25; }
h3 { font-size: 1rem; margin: 1.4em 0 0.3em; }
p { margin: 0.5em 0 1em; }
ul { padding-left: 1.3em; }
.muted { color: var(--muted); }
.small { font-size: 0.875rem; }
.katex { font-size: 1.08em; }
.math-block { text-align: center; line-height: 2.4; padding: 2px 0; overflow-x: auto; overflow-y: hidden; }
.math-block .part { display: inline-block; max-width: 100%; margin: 0 0.6em; }

/* ---------- header ---------- */
.top {
  position: sticky; top: 0; z-index: 20;
  height: var(--top);
  display: flex; align-items: center; gap: 24px;
  padding: 0 24px;
  background: var(--bg);
  border-bottom: 1px solid var(--hair);
}
.brand { font-family: var(--serif); font-size: 1.3rem; color: var(--ink); white-space: nowrap; }
.brand:hover { text-decoration: none; }
.search { position: relative; flex: 1; max-width: 520px; }
.search input {
  width: 100%; height: 34px; padding: 0 12px;
  font: inherit; font-size: 0.9rem; color: var(--ink);
  background: var(--bg-2); border: 1px solid var(--border); border-radius: 2px;
  outline: none;
}
.search input:focus { border-color: var(--accent); background: var(--bg); }
#results {
  position: absolute; top: 38px; left: 0; right: 0;
  margin: 0; padding: 4px 0; list-style: none;
  background: var(--bg); border: 1px solid var(--border); border-radius: 2px;
  box-shadow: 0 6px 24px rgba(0, 0, 0, 0.12);
  max-height: 70vh; overflow-y: auto;
}
#results li a {
  display: flex; justify-content: space-between; gap: 12px;
  padding: 6px 12px; color: var(--ink);
}
#results li a:hover, #results li.sel a { background: var(--bg-2); text-decoration: none; }
#results .r-kind { color: var(--muted); font-size: 0.8rem; white-space: nowrap; }
#results .empty { padding: 6px 12px; color: var(--muted); }
.nav { display: flex; gap: 20px; font-size: 0.9rem; }
.nav a { color: var(--ink-2); }
.nav a.on { color: var(--ink); font-weight: 600; }
.icon-btn {
  display: grid; place-items: center; width: 32px; height: 32px; margin-left: auto;
  color: var(--ink-2); background: none; border: 0; border-radius: 2px; cursor: pointer;
}
.icon-btn:hover { background: var(--bg-2); }

/* ---------- page layouts ---------- */
.wrap { max-width: 1180px; margin: 0 auto; padding: 0 24px 80px; }
.layout { display: grid; grid-template-columns: 190px minmax(0, 1fr); gap: 48px; }
.toc {
  position: sticky; top: calc(var(--top) + 24px); align-self: start;
  margin-top: 32px; font-size: 0.85rem;
  max-height: calc(100vh - var(--top) - 48px); overflow-y: auto;
}
.toc b { display: block; margin-bottom: 6px; font-size: 0.8rem; color: var(--muted); font-weight: 600; text-transform: uppercase; letter-spacing: 0.05em; }
.toc a { display: block; padding: 3px 0 3px 10px; color: var(--ink-2); border-left: 2px solid var(--hair); }
.toc a:hover { color: var(--link); text-decoration: none; border-left-color: var(--border); }
.toc a .n { color: var(--muted); }

article { min-width: 0; padding-top: 20px; }
.crumbs { font-size: 0.85rem; color: var(--muted); }
.crumbs a { color: var(--muted); }
article h1 { font-size: 2.1rem; margin: 4px 0 0; padding-bottom: 4px; border-bottom: 1px solid var(--border); }
.tagline { font-size: 0.875rem; color: var(--muted); margin: 6px 0 18px; }
article h2 { font-size: 1.5rem; margin: 1.6em 0 0.5em; padding-bottom: 3px; border-bottom: 1px solid var(--border); clear: both; }
article h2 .n { font-family: var(--sans); font-size: 0.9rem; color: var(--muted); margin-left: 6px; }
.lead { font-size: 1.06rem; }
.callout { border-left: 3px solid var(--border); padding: 2px 0 2px 14px; color: var(--ink-2); }

/* infobox */
.infobox {
  float: right; width: 320px; margin: 0 0 20px 28px;
  background: var(--bg-2); border: 1px solid var(--border);
  font-size: 0.875rem;
}
.infobox .formula { padding: 16px 14px; border-bottom: 1px solid var(--border); background: var(--bg); text-align: center; }
.infobox table { width: 100%; border-collapse: collapse; }
.infobox th, .infobox td { padding: 6px 12px; text-align: left; vertical-align: top; border-top: 1px solid var(--hair); }
.infobox tr:first-child th, .infobox tr:first-child td { border-top: 0; }
.infobox th { width: 38%; color: var(--ink-2); font-weight: 600; }

/* relation lists */
.rels { margin: 0.3em 0 1em; padding: 0; list-style: none; }
.rels li { margin: 0 0 0.55em; padding-left: 14px; position: relative; }
.rels li::before { content: ""; position: absolute; left: 0; top: 0.72em; width: 5px; height: 5px; border-radius: 50%; background: var(--border); }
.rels .x { color: var(--ink-2); }
.rels .here { margin-top: 2px; color: var(--muted); font-size: 0.9em; }
.rel-h { display: flex; align-items: center; gap: 10px; }
.rel-h svg { flex: none; }
.cols { columns: 3 220px; column-gap: 32px; }
.cols li { break-inside: avoid; }
.plain { list-style: none; padding: 0; margin: 0.4em 0 1em; }
.plain li { margin: 0 0 0.35em; }

/* figure (ego graph) */
.figure { margin: 8px 0 20px; border: 1px solid var(--hair); background: var(--bg); }
.figure-bar {
  display: flex; flex-wrap: wrap; align-items: center; gap: 16px;
  padding: 8px 12px; border-bottom: 1px solid var(--hair);
  font-size: 0.8rem; color: var(--muted);
}
.figure-bar label { display: flex; align-items: center; gap: 6px; cursor: pointer; color: var(--ink-2); }
.figure-bar .spacer { flex: 1; }
.figure-scroll { overflow-x: auto; }
.ego { display: block; margin: 0 auto; font-family: var(--sans); }
.ego text { fill: var(--ink); font-size: 12.5px; }
.ego .head { fill: var(--muted); font-size: 10.5px; font-weight: 600; letter-spacing: 0.06em; text-transform: uppercase; }
.ego .edge { fill: none; stroke-width: 1.4; transition: opacity 0.12s; }
.ego .nb { cursor: pointer; }
.ego .nb circle { fill: var(--bg); stroke-width: 1.6; }
.ego .nb .hit { fill: transparent; }
.ego .nb:hover text { fill: var(--link); text-decoration: underline; }
.ego.hot .edge { opacity: 0.12; }
.ego.hot .edge.on { opacity: 1; stroke-width: 2.4; }
.ego.hot .nb { opacity: 0.45; }
.ego.hot .nb.on { opacity: 1; }
.ego .focal rect { fill: var(--ink); }
.ego .focal text { fill: var(--bg); font-weight: 600; font-size: 13px; }
.ego .empty { fill: var(--muted); font-size: 13px; }

.r-generalization { stroke: var(--rel-gen); }
.r-derivation { stroke: var(--rel-der); }
.r-application { stroke: var(--rel-app); }
.r-equivalence { stroke: var(--ink); }
.r-duality { stroke: var(--ink-2); stroke-dasharray: 1 3.5; stroke-linecap: round; }
.r-analogy { stroke: var(--ink-2); stroke-dasharray: 5 4; }
.r-prerequisite { stroke: var(--border); }

/* tooltip */
.tip {
  position: fixed; z-index: 50; max-width: 340px; pointer-events: none;
  padding: 8px 10px; font-size: 0.82rem; line-height: 1.45;
  background: var(--bg); color: var(--ink);
  border: 1px solid var(--border); border-radius: 2px;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.14);
}
.tip b { display: block; }
.tip .m { color: var(--muted); font-size: 0.78rem; }
.tip p { margin: 4px 0 0; color: var(--ink-2); }
.tip .tip-formula { margin: 8px 0 6px; font-size: 0.95rem; overflow: hidden; }

/* ---------- home ---------- */
.hero { padding: 48px 0 8px; max-width: 760px; }
.hero h1 { font-size: 2.8rem; margin: 0 0 12px; }
.hero p { font-size: 1.1rem; color: var(--ink-2); }
.stats { display: flex; flex-wrap: wrap; gap: 8px 28px; margin: 18px 0 0; font-size: 0.9rem; color: var(--muted); }
.stats b { color: var(--ink); font-weight: 600; font-size: 1.05rem; margin-right: 4px; }
.home-grid { display: grid; grid-template-columns: minmax(0, 1fr) 340px; gap: 48px; margin-top: 28px; }
.home h2 { font-size: 1.45rem; margin: 1.4em 0 0.5em; padding-bottom: 3px; border-bottom: 1px solid var(--border); }
.preview { display: block; position: relative; border: 1px solid var(--hair); background: var(--bg); }
.preview canvas { display: block; width: 100%; height: 440px; }
.preview span { position: absolute; right: 12px; bottom: 10px; font-size: 0.85rem; background: var(--bg); padding: 2px 8px; border: 1px solid var(--hair); }
.region { margin-bottom: 18px; }
.region h3 { margin: 0 0 4px; font-size: 0.8rem; text-transform: uppercase; letter-spacing: 0.05em; color: var(--muted); }
.region ul { margin: 0; padding: 0; list-style: none; columns: 2 200px; column-gap: 24px; }
.region li { margin: 0 0 2px; }
.region .n, .count { color: var(--muted); font-size: 0.85rem; margin-left: 4px; }
.path { counter-reset: step; list-style: none; padding: 0; margin: 0.5em 0; }
.path li { counter-increment: step; position: relative; padding: 0 0 12px 34px; }
.path li::before {
  content: counter(step); position: absolute; left: 0; top: 1px;
  width: 22px; height: 22px; border-radius: 50%;
  display: grid; place-items: center;
  font-size: 0.75rem; color: var(--ink-2); border: 1px solid var(--border);
}
.path .x { display: block; color: var(--ink-2); font-size: 0.9rem; }
.card { border: 1px solid var(--border); background: var(--bg-2); padding: 14px 16px; margin-bottom: 20px; }
.card h3 { margin: 0 0 6px; }
.card p { margin: 0 0 8px; color: var(--ink-2); font-size: 0.92rem; }

/* ---------- index tables ---------- */
.table { width: 100%; border-collapse: collapse; font-size: 0.92rem; margin: 0.5em 0 1.5em; }
.table th { text-align: left; font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.05em; color: var(--muted); font-weight: 600; border-bottom: 1px solid var(--border); padding: 6px 10px 6px 0; }
.table td { border-bottom: 1px solid var(--hair); padding: 8px 10px 8px 0; vertical-align: top; }
.table td.formula { max-width: 280px; overflow-x: auto; }
.table td.num { color: var(--muted); text-align: right; font-variant-numeric: tabular-nums; }
details { margin: 0 0 6px; }
details > summary { cursor: pointer; padding: 4px 0; color: var(--ink); }
details > summary .count { margin-left: 6px; }
details[open] > summary { margin-bottom: 4px; }
details .rels { margin-left: 4px; }

/* ---------- map ---------- */
body.is-map { overflow: hidden; }
.map { position: fixed; top: var(--top); left: 0; right: 0; bottom: 0; background: var(--bg); }
.map canvas { display: block; width: 100%; height: 100%; cursor: grab; }
.map canvas:active { cursor: grabbing; }
.map-hint { position: absolute; left: 16px; bottom: 12px; font-size: 0.78rem; color: var(--muted); pointer-events: none; }
.map-legend { position: absolute; left: 16px; top: 14px; font-size: 0.78rem; color: var(--muted); display: flex; flex-direction: column; gap: 4px; pointer-events: none; }
.map-legend span { display: flex; align-items: center; gap: 8px; }
.map-panel {
  position: absolute; top: 12px; right: 12px; bottom: 12px; width: 480px; max-width: calc(100% - 120px);
  display: flex; flex-direction: column;
  background: var(--bg); border: 1px solid var(--border);
  box-shadow: 0 6px 24px rgba(0, 0, 0, 0.1);
  font-size: 0.9rem;
}
.map-panel[hidden] { display: none; }
.map-panel .panel-body { flex: 1; overflow-y: auto; padding: 16px 20px 20px; }
.map-panel .panel-tools { position: absolute; top: 8px; right: 10px; display: flex; gap: 2px; z-index: 1; background: var(--bg); }
.map-panel .panel-tools .icon-btn { margin: 0; }
.map-panel .expand[aria-pressed="true"] svg { transform: scaleX(-1); }
.map-panel .grip { position: absolute; left: -4px; top: 0; bottom: 0; width: 8px; cursor: ew-resize; z-index: 2; touch-action: none; }
.map-panel .grip::after { content: ""; position: absolute; left: 3px; top: 50%; width: 2px; height: 36px; margin-top: -18px; border-radius: 1px; background: var(--border); }
.map-panel .grip:hover::after { background: var(--accent); }
.map-panel h2 { font-size: 1.45rem; margin: 2px 0 2px; padding-right: 64px; }
.map-panel .crumbs { padding-right: 64px; }
.map-panel .formula { margin: 12px 0; padding: 10px 0; border-top: 1px solid var(--hair); border-bottom: 1px solid var(--hair); }
.map-panel h3 { font-size: 0.75rem; text-transform: uppercase; letter-spacing: 0.05em; color: var(--muted); margin: 14px 0 4px; }
.map-panel .plain a { cursor: pointer; }

/* ---------- responsive ---------- */
@media (max-width: 960px) {
  .layout { grid-template-columns: minmax(0, 1fr); }
  .toc { display: none; }
  .home-grid { grid-template-columns: minmax(0, 1fr); gap: 0; }
}
@media (max-width: 720px) {
  :root { --top: 92px; }
  .top { flex-wrap: wrap; gap: 8px 12px; padding: 10px 16px 0; align-content: flex-start; }
  .brand { font-size: 0.95rem; }
  .search { order: 3; flex-basis: 100%; max-width: none; }
  .nav { gap: 10px; font-size: 0.8rem; margin-left: auto; }
  .icon-btn { display: none; }
  .figure { display: none; }
  .wrap { padding: 0 16px 60px; }
  .infobox { float: none; width: auto; margin: 0 0 20px; }
  article h1 { font-size: 1.7rem; }
  .hero h1 { font-size: 2.1rem; }
  .map-panel { top: auto; left: 8px; right: 8px; bottom: 8px; width: auto !important; max-width: none; max-height: 50%; }
  .map-panel .grip, .map-panel .expand { display: none; }
}