/* Dissection theatre: a reading column beside a 3D stage.
 *
 * The column is paper (a Distill-style article, light, serif prose). The stage
 * is dark, because colour-coded tensors read best as light on dark. On a phone
 * the stage sits on top and the column scrolls beneath it.
 *
 * Pieces may override the --dx-* variables in their own <style> block; they
 * should not restyle the structure.
 */

:root {
  --dx-paper: #fbfaf6;
  --dx-paper-2: #f3f1ea;
  --dx-ink: #191c22;
  --dx-ink-2: #3c424d;
  --dx-muted: #6a7180;
  --dx-rule: #e3dfd4;
  --dx-accent: #d9480f;
  --dx-accent-ink: #ffffff;
  --dx-link: #1d4ed8;
  --dx-stage: #0a0e16;
  --dx-stage-2: #131b2b;
  --dx-stage-ink: #dfe6f3;
  --dx-stage-muted: #8b97ad;
  --dx-glass: rgba(14, 19, 30, 0.78);
  --dx-glass-line: rgba(160, 180, 220, 0.18);
  --dx-act-neg: #3d9bff;
  --dx-act-pos: #ffb340;
  --dx-w-neg: #8a6bff;
  --dx-w-pos: #2fe0c0;
  --dx-prob: #ff5c93;
  --dx-prob-hot: #ffe48a;
  --dx-mask: #ff4d4d;
  --dx-serif: "Source Serif 4", "Source Serif Pro", Georgia, "Times New Roman", serif;
  --dx-sans: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --dx-mono: "JetBrains Mono", ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
  --dx-bar-h: 52px;
  --dx-col-w: clamp(380px, 36vw, 560px);
}

* { box-sizing: border-box; }
html, body { margin: 0; height: 100%; }
body.dx {
  background: var(--dx-stage);
  color: var(--dx-ink);
  font-family: var(--dx-sans);
  -webkit-font-smoothing: antialiased;
  overflow: hidden;
}

/* ── frame ─────────────────────────────────────────────────────────────── */
.dx-app {
  position: fixed; inset: 0;
  display: grid;
  grid-template-columns: var(--dx-col-w) 1fr;
  grid-template-rows: var(--dx-bar-h) 1fr;
  grid-template-areas: "bar bar" "story stage";
}
.dx-bar {
  grid-area: bar;
  display: flex; align-items: center; gap: 14px;
  padding: 0 14px 0 18px;
  background: #0d121c;
  color: var(--dx-stage-ink);
  border-bottom: 1px solid var(--dx-glass-line);
  z-index: 5;
  min-width: 0;
}
.dx-brand { display: flex; flex-direction: column; min-width: 0; line-height: 1.15; }
.dx-brand b { font-size: 14px; font-weight: 650; letter-spacing: .01em; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.dx-brand span { font-size: 11px; color: var(--dx-stage-muted); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.dx-input { display: flex; align-items: center; gap: 8px; margin-left: auto; min-width: 0; }
.dx-input label { font-size: 11px; text-transform: uppercase; letter-spacing: .08em; color: var(--dx-stage-muted); white-space: nowrap; }
.dx-input input {
  width: 150px; height: 32px; border-radius: 8px;
  border: 1px solid var(--dx-glass-line); background: #121a29; color: #fff;
  font: 500 14px var(--dx-mono); padding: 0 10px;
}
.dx-input input:focus { outline: 2px solid var(--dx-accent); outline-offset: 1px; }
.dx-input .dx-chips { display: flex; gap: 6px; }
.dx-chip {
  height: 28px; padding: 0 10px; border-radius: 999px; border: 1px solid var(--dx-glass-line);
  background: transparent; color: var(--dx-stage-ink); font: 500 12px var(--dx-mono); cursor: pointer; white-space: nowrap;
}
.dx-chip:hover { border-color: var(--dx-accent); color: #fff; }
.dx-input .dx-err { font-size: 12px; color: #ff8a8a; max-width: 220px; }
.dx-ctrls { display: flex; gap: 4px; }
.dx-btn {
  width: 34px; height: 34px; border-radius: 8px; border: 1px solid transparent; background: transparent;
  color: var(--dx-stage-ink); cursor: pointer; display: grid; place-items: center; padding: 0;
}
.dx-btn svg { width: 18px; height: 18px; fill: currentColor; }
.dx-btn:hover { background: rgba(255,255,255,.07); border-color: var(--dx-glass-line); }
.dx-btn[aria-pressed="true"] { color: var(--dx-accent); }
.dx-btn:focus-visible, .dx-chip:focus-visible { outline: 2px solid var(--dx-accent); outline-offset: 1px; }

/* ── the reading column ───────────────────────────────────────────────── */
.dx-story {
  grid-area: story;
  background: var(--dx-paper);
  overflow-y: auto; overflow-x: hidden;
  scroll-behavior: smooth;
  border-right: 1px solid #000;
  position: relative;
  overscroll-behavior: contain;
}
.dx-progress { position: sticky; top: 0; height: 3px; background: transparent; z-index: 3; }
.dx-progress i { display: block; height: 100%; width: 0; background: var(--dx-accent); transition: width .2s; }
.dx-toc {
  position: sticky; top: 3px; z-index: 2;
  background: rgba(251, 250, 246, .94); backdrop-filter: blur(6px);
  border-bottom: 1px solid var(--dx-rule);
  font-size: 12.5px;
}
.dx-toc summary {
  list-style: none; cursor: pointer; padding: 10px 26px; display: flex; gap: 10px; align-items: baseline;
  color: var(--dx-ink-2);
}
.dx-toc summary::-webkit-details-marker { display: none; }
.dx-toc summary b { font-weight: 650; color: var(--dx-ink); }
.dx-toc summary .dx-count { margin-left: auto; font-family: var(--dx-mono); color: var(--dx-muted); font-size: 11.5px; }
.dx-toc ol { margin: 0; padding: 4px 26px 14px 26px; list-style: none; max-height: 52vh; overflow: auto; columns: 1; }
.dx-toc li { break-inside: avoid; }
.dx-toc .dx-toc-ch { margin: 10px 0 2px; font-size: 10.5px; text-transform: uppercase; letter-spacing: .1em; color: var(--dx-muted); }
.dx-toc a { display: flex; gap: 8px; padding: 3px 0; color: var(--dx-ink-2); text-decoration: none; }
.dx-toc a span { font-family: var(--dx-mono); color: var(--dx-muted); min-width: 22px; }
.dx-toc a:hover, .dx-toc a[aria-current="step"] { color: var(--dx-accent); }

.dx-article { padding: 0 34px 60px; color: var(--dx-ink); }
.dx-hero { padding: 38px 0 18px; border-bottom: 1px solid var(--dx-rule); margin-bottom: 8px; }
.dx-kicker { font: 600 11px var(--dx-sans); text-transform: uppercase; letter-spacing: .14em; color: var(--dx-accent); }
.dx-hero h1 { font: 700 clamp(28px, 2.6vw, 38px)/1.08 var(--dx-serif); letter-spacing: -.012em; margin: 10px 0 12px; }
.dx-hero .dx-dek { font: 400 18px/1.5 var(--dx-serif); color: var(--dx-ink-2); margin: 0 0 18px; }
.dx-byline { display: grid; grid-template-columns: repeat(auto-fit, minmax(120px, 1fr)); gap: 10px 18px; font-size: 12px; color: var(--dx-muted); }
.dx-byline b { display: block; font-weight: 600; color: var(--dx-ink-2); font-size: 10.5px; text-transform: uppercase; letter-spacing: .08em; margin-bottom: 2px; }

.dx-step {
  padding: 30px 0 34px;
  border-bottom: 1px solid var(--dx-rule);
  scroll-margin-top: 48px;
  position: relative;
}
.dx-step::before {
  content: ""; position: absolute; left: -34px; top: 30px; bottom: 34px; width: 3px;
  background: transparent; transition: background .3s;
}
.dx-step.is-active::before { background: var(--dx-accent); }
.dx-step-meta { display: flex; gap: 10px; align-items: baseline; font: 600 10.5px var(--dx-sans); text-transform: uppercase; letter-spacing: .12em; color: var(--dx-muted); margin-bottom: 6px; }
.dx-step-meta .dx-n { font-family: var(--dx-mono); color: var(--dx-accent); letter-spacing: 0; font-size: 11.5px; }
.dx-step h2 { font: 700 23px/1.2 var(--dx-serif); margin: 0 0 12px; letter-spacing: -.005em; }
.dx-step h3 { font: 650 15px/1.3 var(--dx-sans); margin: 22px 0 6px; }
.dx-article p, .dx-article li { font: 400 16.5px/1.62 var(--dx-serif); color: var(--dx-ink); }
.dx-article p { margin: 0 0 14px; }
.dx-article ul, .dx-article ol { padding-left: 22px; margin: 0 0 14px; }
.dx-article li { margin: 4px 0; }
.dx-article a { color: var(--dx-link); text-decoration-thickness: 1px; text-underline-offset: 2px; }
.dx-article code { font: 500 .86em var(--dx-mono); background: var(--dx-paper-2); padding: 1px 5px; border-radius: 4px; }
.dx-article strong { font-weight: 650; }
.dx-article .katex { font-size: 1.04em; }
.dx-article .katex-display { margin: 14px 0 16px; padding: 12px 8px; background: #fff; border: 1px solid var(--dx-rule); border-radius: 8px; overflow-x: auto; overflow-y: hidden; }

.dx-lede { font-size: 17.5px !important; }
.dx-note {
  margin: 16px 0; padding: 12px 14px; border-left: 3px solid var(--dx-ink-2); background: var(--dx-paper-2);
  font: 400 14px/1.55 var(--dx-sans); color: var(--dx-ink-2); border-radius: 0 6px 6px 0;
}
.dx-note b:first-child { display: block; font-size: 10.5px; text-transform: uppercase; letter-spacing: .1em; color: var(--dx-ink); margin-bottom: 3px; }
.dx-note p, .dx-note li { font: 400 14px/1.55 var(--dx-sans) !important; }
.dx-note p:last-child { margin-bottom: 0; }
.dx-note.is-caveat { border-left-color: #b45309; background: #fdf6ec; }
.dx-note.is-paper { border-left-color: var(--dx-accent); background: #fff5ef; }
.dx-note.is-live { border-left-color: #0e7490; background: #effafc; }

.dx-try {
  margin: 18px 0; padding: 14px; background: #fff; border: 1px solid var(--dx-rule); border-radius: 10px;
  font: 400 13.5px/1.5 var(--dx-sans); color: var(--dx-ink-2);
}
.dx-try > b:first-child { display: block; font-size: 10.5px; text-transform: uppercase; letter-spacing: .1em; color: var(--dx-accent); margin-bottom: 6px; }

.dx-table { width: 100%; border-collapse: collapse; margin: 12px 0 16px; font: 400 13px/1.4 var(--dx-sans); }
.dx-table th, .dx-table td { padding: 6px 8px; border-bottom: 1px solid var(--dx-rule); text-align: left; vertical-align: top; }
.dx-table th { font-weight: 650; font-size: 11px; text-transform: uppercase; letter-spacing: .06em; color: var(--dx-muted); }
.dx-table td.num, .dx-table th.num { text-align: right; font-family: var(--dx-mono); font-size: 12.5px; }
.dx-table tr.is-hi td { background: #fff5ef; font-weight: 600; }
.dx-scroll { overflow-x: auto; }

/* live numbers from the running model */
.dx-live { font-family: var(--dx-mono); font-size: .9em; background: #e8f6f9; color: #0b4f5c; padding: 0 4px; border-radius: 4px; white-space: nowrap; }
.dx-tok { font-family: var(--dx-mono); font-size: .88em; padding: 1px 6px; border-radius: 5px; background: #eef1f6; border: 1px solid #dde2ea; white-space: nowrap; }
.dx-tok.de { background: #fff1e6; border-color: #f6d3b8; }

/* citations and facts */
.dx-cite { font: 600 .72em var(--dx-sans); color: var(--dx-link); text-decoration: none; vertical-align: super; line-height: 0; padding: 0 1px; cursor: pointer; }
.dx-fact { border-bottom: 1.5px dotted var(--dx-accent); cursor: help; }
.dx-fact:focus { outline: 2px solid var(--dx-accent); outline-offset: 2px; border-radius: 2px; }
.dx-card {
  position: fixed; z-index: 50; max-width: 360px; padding: 12px 14px;
  background: #fff; color: var(--dx-ink); border: 1px solid var(--dx-rule); border-radius: 10px;
  box-shadow: 0 12px 34px rgba(0,0,0,.18); font: 400 13px/1.5 var(--dx-sans); pointer-events: auto;
}
.dx-card .dx-card-k { font-size: 10.5px; text-transform: uppercase; letter-spacing: .1em; color: var(--dx-muted); margin-bottom: 4px; }
.dx-card q { display: block; margin-top: 6px; font: italic 400 13.5px/1.5 var(--dx-serif); color: var(--dx-ink-2); quotes: "\201C" "\201D"; }
.dx-card a { color: var(--dx-link); }

/* appendix */
.dx-appendix { padding-top: 26px; }
.dx-appendix h2 { font: 700 20px var(--dx-serif); margin: 26px 0 10px; }
.dx-refs { padding-left: 26px !important; }
.dx-refs li { font: 400 13.5px/1.5 var(--dx-sans) !important; margin: 6px 0 !important; scroll-margin-top: 60px; }
.dx-refs li:target { background: #fff5ef; }
.dx-refs .dx-ref-note { color: var(--dx-muted); }
.dx-ledger td:first-child { white-space: nowrap; font-family: var(--dx-mono); font-size: 12px; }
.dx-ledger q { font-family: var(--dx-serif); font-style: italic; color: var(--dx-ink-2); }
.dx-bib { font: 400 11.5px/1.5 var(--dx-mono); background: var(--dx-paper-2); padding: 12px; border-radius: 8px; white-space: pre-wrap; word-break: break-word; }
.dx-colophon { font: 400 13px/1.55 var(--dx-sans) !important; color: var(--dx-muted) !important; }

/* widgets */
.dx-widget { margin: 16px 0 18px; }
.dx-w { background: #fff; border: 1px solid var(--dx-rule); border-radius: 10px; padding: 12px; font: 400 12.5px/1.45 var(--dx-sans); color: var(--dx-ink-2); }
.dx-w-title { font: 650 12px var(--dx-sans); color: var(--dx-ink); margin-bottom: 8px; display: flex; gap: 8px; align-items: baseline; }
.dx-w-title small { font-weight: 400; color: var(--dx-muted); }
.dx-w svg { display: block; width: 100%; height: auto; overflow: visible; }
.dx-w canvas { display: block; width: 100%; image-rendering: pixelated; border-radius: 4px; }
.dx-w-row { display: flex; flex-wrap: wrap; gap: 10px 16px; align-items: center; margin-top: 8px; }
.dx-w label { display: flex; align-items: center; gap: 8px; font-size: 12px; color: var(--dx-ink-2); }
.dx-w input[type="range"] { accent-color: var(--dx-accent); width: 140px; }
.dx-w output, .dx-w .dx-w-val { font: 600 12px var(--dx-mono); color: var(--dx-ink); min-width: 3.5em; display: inline-block; }
.dx-w .dx-w-cap { margin-top: 8px; font-size: 12px; color: var(--dx-muted); }
.dx-w button { font: 500 12px var(--dx-sans); border: 1px solid var(--dx-rule); background: var(--dx-paper); border-radius: 6px; padding: 5px 10px; cursor: pointer; color: var(--dx-ink); }
.dx-w button:hover { border-color: var(--dx-accent); }
.dx-w .axis text { font: 400 10px var(--dx-sans); fill: var(--dx-muted); }
.dx-w .axis line, .dx-w .axis path { stroke: #cfd4dc; }
.dx-w .grid line { stroke: #eef0f3; }

/* ── the stage ────────────────────────────────────────────────────────── */
.dx-stage {
  grid-area: stage; position: relative; overflow: hidden;
  background: radial-gradient(120% 90% at 60% 30%, var(--dx-stage-2), var(--dx-stage) 70%);
  color: var(--dx-stage-ink);
  touch-action: none;
}
.dx-stage canvas.dx-gl { position: absolute; inset: 0; width: 100%; height: 100%; display: block; outline: none; }
.dx-labels { position: absolute; inset: 0; pointer-events: none; overflow: hidden; }
.dx-label {
  position: absolute; left: 0; top: 0; transform: translate(-50%, -100%);
  padding: 4px 8px; border-radius: 6px; white-space: nowrap;
  background: var(--dx-glass); border: 1px solid var(--dx-glass-line); backdrop-filter: blur(4px);
  font: 600 12px var(--dx-sans); color: #fff; transition: opacity .25s;
}
.dx-label small { display: block; font: 400 10.5px var(--dx-mono); color: var(--dx-stage-muted); }
.dx-label.is-key { border-color: var(--dx-accent); box-shadow: 0 0 0 1px var(--dx-accent) inset; }
.dx-label.is-callout { background: var(--dx-accent); color: var(--dx-accent-ink); border-color: transparent; }
.dx-label.is-callout small { color: rgba(255,255,255,.82); }

.dx-crumbs {
  position: absolute; left: 14px; top: 12px; z-index: 2;
  font: 500 12px var(--dx-sans); color: var(--dx-stage-muted);
  background: var(--dx-glass); border: 1px solid var(--dx-glass-line); padding: 6px 10px; border-radius: 8px;
  max-width: calc(100% - 28px); white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.dx-crumbs b { color: #fff; font-weight: 600; }
.dx-tip {
  position: absolute; z-index: 4; pointer-events: none; max-width: 300px;
  background: rgba(8, 12, 20, .94); border: 1px solid var(--dx-glass-line); border-radius: 8px;
  padding: 8px 10px; font: 400 12px/1.45 var(--dx-sans); color: var(--dx-stage-ink);
  transform: translate(14px, 14px); display: none;
}
.dx-tip b { color: #fff; }
.dx-tip code { font: 500 11.5px var(--dx-mono); color: #ffd28a; }
.dx-legend {
  position: absolute; right: 14px; bottom: 14px; z-index: 2;
  background: var(--dx-glass); border: 1px solid var(--dx-glass-line); border-radius: 10px;
  padding: 8px 10px; font: 400 11px var(--dx-sans); color: var(--dx-stage-muted);
  display: grid; gap: 5px;
}
.dx-legend div { display: flex; align-items: center; gap: 8px; }
.dx-legend i { width: 64px; height: 8px; border-radius: 3px; display: inline-block; }
.dx-map {
  position: absolute; left: 14px; bottom: 14px; z-index: 2; width: 188px;
  background: var(--dx-glass); border: 1px solid var(--dx-glass-line); border-radius: 10px; padding: 8px;
}
.dx-map svg { display: block; width: 100%; height: auto; }
.dx-map [data-map] { cursor: pointer; transition: fill .25s, stroke .25s, opacity .25s; }
.dx-map [data-map].is-on { fill: var(--dx-accent) !important; stroke: #fff !important; }
.dx-map-k { font: 600 9.5px var(--dx-sans); text-transform: uppercase; letter-spacing: .12em; color: var(--dx-stage-muted); margin: 0 0 5px 2px; }
.dx-stagebar { position: absolute; right: 14px; top: 12px; z-index: 2; display: flex; gap: 6px; }
.dx-stagebar .dx-btn { background: var(--dx-glass); border-color: var(--dx-glass-line); }
.dx-scrub {
  position: absolute; left: 50%; bottom: 14px; transform: translateX(-50%); z-index: 2;
  width: min(360px, 40%); height: 4px; border-radius: 4px; background: rgba(255,255,255,.12); overflow: hidden;
}
.dx-scrub i { display: block; height: 100%; width: 0; background: var(--dx-accent); }
.dx-nogl { position: absolute; inset: 0; display: grid; place-items: center; padding: 30px; text-align: center; color: var(--dx-stage-muted); font-size: 14px; }
.dx-hint {
  position: absolute; left: 50%; top: 14px; transform: translateX(-50%); z-index: 2;
  font: 500 12px var(--dx-sans); color: var(--dx-stage-ink); background: var(--dx-glass);
  border: 1px solid var(--dx-glass-line); border-radius: 999px; padding: 6px 12px; transition: opacity .6s;
}

/* capture mode: the stage alone, for covers */
body.dx-capture .dx-app { grid-template-columns: 0 1fr; grid-template-rows: 0 1fr; }
body.dx-capture .dx-bar, body.dx-capture .dx-story, body.dx-capture .dx-stagebar,
body.dx-capture .dx-scrub, body.dx-capture .dx-hint, body.dx-capture .dx-tip { display: none !important; }
#dx-capture { display: none; }

/* ── phone and narrow frames ─────────────────────────────────────────── */
@media (max-width: 860px) {
  :root { --dx-bar-h: 48px; }
  .dx-app {
    grid-template-columns: 1fr;
    grid-template-rows: var(--dx-bar-h) 46vh 1fr;
    grid-template-areas: "bar" "stage" "story";
  }
  .dx-story { border-right: 0; border-top: 1px solid #000; }
  .dx-article { padding: 0 18px 50px; }
  .dx-step::before { left: -18px; }
  .dx-toc summary, .dx-toc ol { padding-left: 18px; padding-right: 18px; }
  .dx-input label, .dx-input .dx-chips, .dx-brand span { display: none; }
  .dx-input input { width: 104px; }
  .dx-map { width: 132px; padding: 6px; }
  .dx-map-k { display: none; }
  .dx-legend { display: none; }
  .dx-crumbs { font-size: 11px; top: 8px; left: 8px; }
  .dx-stagebar { top: 6px; right: 6px; }
  .dx-hero h1 { font-size: 27px; }
  .dx-article p, .dx-article li { font-size: 16px; }
}
@media (max-width: 520px) {
  .dx-ctrls .dx-btn.is-opt { display: none; }
  .dx-brand b { font-size: 13px; }
}
@media (prefers-reduced-motion: reduce) {
  .dx-story { scroll-behavior: auto; }
  * { transition: none !important; }
}

/* "Go deeper" links into the site's libraries, at the end of a step */
.dx-article p.dx-deeper { font: 500 12.5px/1.6 var(--dx-sans); color: var(--dx-muted); margin: 18px 0 0; padding-top: 10px; border-top: 1px dashed var(--dx-rule); }
.dx-article p.dx-deeper a { color: var(--dx-ink-2); text-decoration-color: var(--dx-accent); }

/* small screens: the stage is short, so keep only what orients the reader */
@media (max-width: 860px) {
  .dx-hint { display: none; }
}
@media (max-width: 600px) {
  .dx-map { display: none; }
  .dx-stagebar .dx-btn[data-act="full"] { display: none; }
}