/* ============================================================================
   bench-kmeans-rust — Tufte editorial stylesheet
   A figure-centric technical essay: paper background, single 720px measure,
   margin sidenotes, restrained tables. See DESIGN_BRIEF.md.
   ============================================================================ */

/* --- Design tokens (authoritative; see brief) ----------------------------- */
:root {
  /* Palette */
  --paper:      #fffff8;   /* Tufte off-white background          */
  --ink:        #151515;   /* body text                          */
  --ink-faint:  #595959;   /* captions, sidenotes, metadata      */
  --rule:       #dcdcd4;   /* hairlines, table rules             */
  --accent:     #a32015;   /* links, emphasis — dark red, sparing */

  /* Implementation palette (mirrors matplotlib / Plotly / demo JS) */
  --c-python:   #3d6b9e;   /* steel blue  — "Python"             */
  --c-sklearn:  #c98c1f;   /* muted ochre — "scikit-learn"       */
  --c-rust:     #b7410e;   /* rust        — "Rust" (serial)      */
  --c-rust-par: #7a2e0c;   /* dark rust   — "Rust — Parallel"    */

  /* Type */
  --serif: "Newsreader", Georgia, "Times New Roman", serif;
  --mono:  "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  --measure:      720px;   /* reading column           */
  --measure-wide: 960px;   /* figure breakout          */
  --line:         1.55;    /* generous body leading    */

  /* Spacing */
  --gap-xs:  0.4rem;
  --gap-sm:  0.8rem;
  --gap:     1.4rem;
  --gap-lg:  2.6rem;
  --gap-xl:  4.5rem;
}

/* --- Reset & base --------------------------------------------------------- */
*, *::before, *::after { box-sizing: border-box; }

html {
  font-size: 18px;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  font-family: var(--serif);
  font-weight: 400;
  font-size: 1rem;
  line-height: var(--line);
  color: var(--ink);
  background: var(--paper);
  font-variant-numeric: oldstyle-nums proportional-nums;
  font-feature-settings: "kern", "liga", "onum";
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

img, canvas, svg, iframe { max-width: 100%; }
img { height: auto; display: block; }

/* --- The measure: header, main, footer all share one centered column ------ */
.site-header,
.site-footer,
.site-main > * {
  max-width: var(--measure);
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.5rem;
  padding-right: 1.5rem;
}

.site-main {
  padding-top: var(--gap-lg);
  padding-bottom: var(--gap-xl);
}

/* --- Header: small-caps title left, quiet nav right, hairline rule -------- */
.site-header {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.6rem 1.4rem;
  padding-top: 1.4rem;
  padding-bottom: 1rem;
  margin-bottom: var(--gap-lg);
  border-bottom: 1px solid var(--rule);
}

.site-title {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 0.92rem;
  font-variant: small-caps;
  letter-spacing: 0.06em;
  color: var(--ink);
  text-decoration: none;
  border: 0;
}

.site-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.2rem 1.1rem;
  margin-left: auto;
  font-size: 0.82rem;
}

.site-nav a {
  color: var(--ink-faint);
  text-decoration: none;
  border: 0;
  font-variant: small-caps;
  letter-spacing: 0.03em;
}
.site-nav a:hover { color: var(--accent); }

/* --- Footer: quiet metadata line ------------------------------------------ */
.site-footer {
  margin-top: var(--gap-xl);
  padding-top: 1.2rem;
  padding-bottom: 2.4rem;
  border-top: 1px solid var(--rule);
  color: var(--ink-faint);
  font-size: 0.82rem;
  font-style: italic;
}
.site-footer p { margin: 0; }

/* --- Headings: Newsreader, not bold-heavy; h3 italic; never uppercase ----- */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--serif);
  color: var(--ink);
  line-height: 1.2;
  font-weight: 600;
}

h1 {
  font-weight: 600;
  font-size: 2.3rem;
  line-height: 1.12;
  letter-spacing: -0.01em;
  margin: 0 0 var(--gap);
}

h2 {
  font-size: 1.5rem;
  font-weight: 600;
  margin: var(--gap-xl) 0 var(--gap-sm);
}

h3 {
  font-size: 1.2rem;
  font-style: italic;
  font-weight: 400;
  margin: var(--gap-lg) 0 var(--gap-sm);
}

h4, h5, h6 {
  font-size: 0.78rem;
  font-weight: 600;
  font-variant: small-caps;
  letter-spacing: 0.06em;
  color: var(--ink-faint);
  margin: var(--gap) 0 var(--gap-xs);
}

/* --- Prose ---------------------------------------------------------------- */
p { margin: 0 0 var(--gap); }

/* A page's opening paragraph (kramdown adds no class, so style first p after
   an epigraph or h1 only if explicitly marked) */
p.lead {
  font-size: 1.18rem;
  line-height: 1.5;
  color: var(--ink);
  margin-bottom: var(--gap-lg);
}

strong { font-weight: 600; }
em { font-style: italic; }

/* Subtle accent underline on links */
a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid rgba(163, 32, 21, 0.32);
  transition: border-color 120ms ease, color 120ms ease;
}
a:hover { border-bottom-color: var(--accent); }

/* --- newthought: small-caps run-in opener --------------------------------- */
.newthought {
  font-variant: small-caps;
  font-style: normal;
  letter-spacing: 0.03em;
  font-size: 1.08em;
}

/* --- Epigraph: opening quote / summary block ------------------------------ */
.epigraph {
  margin: 0 auto var(--gap-lg);
  font-style: italic;
  color: var(--ink-faint);
  line-height: 1.5;
}
.epigraph p { margin: 0 0 var(--gap-sm); }
.epigraph footer,
.epigraph cite {
  display: block;
  font-style: normal;
  font-size: 0.82rem;
  font-variant: small-caps;
  letter-spacing: 0.04em;
  color: var(--ink-faint);
}

/* Plain markdown blockquotes — light, no boxy fill */
blockquote {
  margin: var(--gap) 0;
  padding-left: 1.2rem;
  border-left: 2px solid var(--rule);
  color: var(--ink-faint);
  font-style: italic;
}
blockquote p:last-child { margin-bottom: 0; }

/* --- Code: JetBrains Mono, 0.85em inside prose ---------------------------- */
code, pre, kbd, samp {
  font-family: var(--mono);
  font-variant-numeric: normal;
  font-feature-settings: normal;
}

code {
  font-size: 0.85em;
  background: rgba(21, 21, 21, 0.045);
  padding: 0.08em 0.34em;
  border-radius: 2px;
}

pre {
  font-size: 0.82rem;
  line-height: 1.5;
  background: rgba(21, 21, 21, 0.045);
  border: 1px solid var(--rule);
  border-radius: 3px;
  padding: 1rem 1.1rem;
  margin: var(--gap) 0;
  overflow-x: auto;
}
pre code {
  background: none;
  padding: 0;
  font-size: inherit;
}

/* --- Lists ---------------------------------------------------------------- */
ul, ol {
  margin: 0 0 var(--gap);
  padding-left: 1.4rem;
}
li { margin: 0.25rem 0; }

/* --- Tables: top/bottom rules only, no zebra, tabular numerals ------------ */
table {
  width: 100%;
  border-collapse: collapse;
  margin: var(--gap-lg) 0;
  font-size: 0.9rem;
  font-variant-numeric: tabular-nums lining-nums;
}
thead th {
  border-top: 1px solid var(--ink);
  border-bottom: 1px solid var(--ink);
}
table tbody tr:last-child td {
  border-bottom: 1px solid var(--ink);
}
th, td {
  padding: 0.45rem 0.9rem 0.45rem 0;
  text-align: left;
  vertical-align: baseline;
}
th {
  font-weight: 600;
  font-variant: small-caps;
  letter-spacing: 0.03em;
  color: var(--ink-faint);
}
/* numeric columns read better right-aligned, but keep it opt-in via markup */
td.num, th.num { text-align: right; font-variant-numeric: tabular-nums; }

/* --- Horizontal rule ------------------------------------------------------ */
hr {
  border: 0;
  border-top: 1px solid var(--rule);
  margin: var(--gap-xl) 0;
}

/* --- Figures: every chart/image gets a caption stating the takeaway ------- */
figure {
  margin: var(--gap-lg) 0;
}
figure img,
figure canvas,
figure iframe,
figure svg {
  display: block;
  margin: 0 auto;
}
figcaption {
  margin-top: var(--gap-sm);
  font-size: 0.82rem;
  line-height: 1.45;
  color: var(--ink-faint);
  font-style: italic;
}
figcaption .label,
figcaption b,
figcaption strong {
  font-style: normal;
  font-variant: small-caps;
  letter-spacing: 0.04em;
  font-weight: 600;
  color: var(--ink);
}

/* Wide figures break the measure out to ~960px, centered on the viewport */
.figure-wide {
  width: min(var(--measure-wide), calc(100vw - 3rem));
  max-width: none;
  margin-left: 50%;
  transform: translateX(-50%);
}
.figure-wide img,
.figure-wide iframe { width: 100%; }

/* Animation grid: 3+2 layout for the convergence GIF strip */
.anim-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.2rem 1.4rem;
  margin-bottom: 0.6rem;
}
.anim-grid figure {
  margin: 0;
  padding: 0;
}
.anim-grid figure img { width: 100%; }
.anim-grid figure figcaption {
  margin-top: 0.25rem;
  font-size: 0.78rem;
  font-style: normal;
  font-variant: small-caps;
  letter-spacing: 0.04em;
  text-align: center;
}
@media (max-width: 900px) {
  .anim-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 560px) {
  .anim-grid { grid-template-columns: 1fr; }
}

iframe {
  border: 1px solid var(--rule);
  background: var(--paper);
}

/* --- Sidenotes (Tufte numbered-margin pattern) ---------------------------- */
/* Markup contract (kept identical to the brief's class names):
     <label for="sn-N" class="sidenote-toggle">N</label>
     <input type="checkbox" id="sn-N" class="sidenote-state">
     <span class="sidenote">note text…</span>
   ≥1280px: note sits in the right margin, toggle is a quiet superscript.
   <1280px: note is hidden until the toggle (⊕) is clicked, then it expands
            inline as small print. */

.sidenote-toggle {
  display: inline;
  cursor: pointer;
  color: var(--accent);
  font-size: 0.7em;
  vertical-align: super;
  line-height: 0;
  border: 0;
  -webkit-user-select: none;
  user-select: none;
}

/* The checkbox is the toggle mechanism; never shown */
.sidenote-state {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0 0 0 0);
  white-space: nowrap; border: 0;
}

.sidenote {
  font-size: 0.78rem;
  line-height: 1.4;
  color: var(--ink-faint);
}

/* Narrow / default: inline collapsible small-print note */
@media (max-width: 1279.98px) {
  .sidenote {
    display: none;
    margin: var(--gap-sm) 0;
    padding-left: 1rem;
    border-left: 2px solid var(--rule);
  }
  .sidenote-state:checked + .sidenote { display: block; }
}

/* Wide: float the note into the right margin, no toggle needed ------------- */
@media (min-width: 1280px) {
  .site-main > * {
    /* keep the text column where it is, let .sidenote escape rightward */
    position: relative;
  }
  .sidenote-toggle {
    /* show the marker as a superscript number; clicking is a no-op here */
    cursor: default;
    pointer-events: none;
  }
  .sidenote {
    float: right;
    clear: right;
    width: 14rem;
    margin-right: -16rem;   /* push past the measure into the right margin */
    margin-top: 0.2rem;
    margin-bottom: var(--gap-sm);
    display: block;
  }
}

/* --- Eyebrow (small-caps kicker above a heading) -------------------------- */
.eyebrow {
  display: block;
  font-variant: small-caps;
  letter-spacing: 0.08em;
  font-size: 0.78rem;
  color: var(--ink-faint);
  margin-bottom: var(--gap-xs);
}

/* --- Implementation colour helpers ---------------------------------------- */
.lang-py,       .impl-python   { color: var(--c-python); }
.lang-sklearn,  .impl-sklearn  { color: var(--c-sklearn); }
.lang-rust,     .impl-rust     { color: var(--c-rust); }
.lang-rust-par, .impl-rust-par { color: var(--c-rust-par); }

/* ===========================================================================
   LIVE DEMO  (docs/demo.md + docs/assets/js/demo.js)
   Class & id names below are load-bearing — do not rename. Styled quietly:
   hairline borders, paper background, serif labels.
   =========================================================================== */

/* Let the demo use the wider measure so the canvas + controls breathe */
.demo-grid {
  max-width: var(--measure-wide);
  margin-left: 50%;
  transform: translateX(-50%);
  display: grid;
  grid-template-columns: minmax(220px, 280px) minmax(0, 1fr);
  gap: var(--gap-lg);
  align-items: start;
  margin-top: var(--gap-lg);
  margin-bottom: var(--gap-lg);
}

.demo-controls {
  display: flex;
  flex-direction: column;
  gap: var(--gap-sm);
  position: sticky;
  top: 1rem;
}

.demo-controls label {
  display: block;
  font-family: var(--serif);
  font-size: 0.85rem;
  color: var(--ink);
}

.demo-controls label span {
  font-variant-numeric: tabular-nums;
  color: var(--ink-faint);
}

/* Range sliders — restrained, accent thumb */
.demo-controls input[type="range"] {
  width: 100%;
  margin-top: 0.3rem;
  accent-color: var(--accent);
}

/* Selects — hairline border, paper background */
.demo-controls select {
  width: 100%;
  margin-top: 0.25rem;
  font-family: var(--serif);
  font-size: 0.85rem;
  color: var(--ink);
  background: var(--paper);
  border: 1px solid var(--rule);
  border-radius: 2px;
  padding: 0.35rem 0.5rem;
}
.demo-controls select:hover { border-color: var(--ink-faint); }

/* Buttons — only the demo has genuine controls; quiet outline style */
.demo-controls button {
  appearance: none;
  font-family: var(--serif);
  font-size: 0.85rem;
  font-variant: small-caps;
  letter-spacing: 0.03em;
  color: var(--ink);
  background: var(--paper);
  border: 1px solid var(--ink-faint);
  border-radius: 2px;
  padding: 0.35rem 0.9rem;
  cursor: pointer;
  transition: background 120ms ease, color 120ms ease, border-color 120ms ease;
}
.demo-controls button:hover {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--paper);
}
.demo-controls button:disabled {
  color: var(--rule);
  border-color: var(--rule);
  background: var(--paper);
  cursor: not-allowed;
}

/* Button row under the sliders */
.demo-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: var(--gap-sm);
  margin-top: var(--gap-sm);
}

/* Visual column: canvas + inertia chart */
.demo-visual {
  display: flex;
  flex-direction: column;
  gap: var(--gap-sm);
  align-items: center;
}

.demo-canvas-wrap {
  width: 100%;
  text-align: center;
}

#demo-canvas {
  width: 100%;
  max-width: 480px;
  height: auto;
  aspect-ratio: 1 / 1;
  border: 1px solid var(--rule);
  background: var(--paper);
}

.inertia-wrap {
  width: 100%;
  max-width: 480px;
}
.inertia-wrap h5 {
  margin: 0.8rem 0;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.03em;
  text-transform: uppercase;
  color: var(--ink-faint);
}

#inertia-canvas {
  width: 100%;
  max-width: 480px;
  height: auto;
  aspect-ratio: 4 / 1;
  border: 1px solid var(--rule);
  background: var(--paper);
  display: block;
}

#demo-status {
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--ink-faint);
  text-align: center;
  margin: 0.4rem 0 0;
}

.race-result {
  font-family: var(--mono);
  font-size: 0.82rem;
  color: var(--ink-faint);
  text-align: center;
  margin: 0.3rem 0 0;
}
/* spans injected by demo.js into .race-result */
.race-result .rust { color: var(--c-rust); font-weight: 500; }
.race-result .js   { color: var(--c-python); font-weight: 500; }

/* --- KaTeX: match the page measure, never overflow ------------------------ */
.katex { font-size: 1.02em; }
.katex-display {
  margin: var(--gap) 0;
  overflow-x: auto;
  overflow-y: hidden;
}

/* ===========================================================================
   ACCESSIBILITY
   =========================================================================== */

/* Visible focus on everything interactive */
a:focus-visible,
button:focus-visible,
select:focus-visible,
input:focus-visible,
.sidenote-toggle:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-radius: 2px;
}

/* Respect reduced-motion for every transition on the page */
@media (prefers-reduced-motion: reduce) {
  * {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    scroll-behavior: auto !important;
  }
}

/* ===========================================================================
   RESPONSIVE  (readable down to 375px)
   =========================================================================== */

@media (max-width: 760px) {
  html { font-size: 17px; }

  .demo-grid {
    /* drop the breakout; stack controls above the canvas */
    max-width: 100%;
    margin-left: 0;
    transform: none;
    grid-template-columns: 1fr;
    gap: var(--gap);
  }
  .demo-controls { position: static; }

  /* charts that broke out collapse back to full width */
  .figure-wide {
    max-width: 100%;
    margin-left: 0;
    transform: none;
  }
}

@media (max-width: 420px) {
  html { font-size: 16px; }

  .site-header { gap: 0.4rem 0.9rem; }
  .site-nav { font-size: 0.78rem; gap: 0.15rem 0.8rem; }
  h1 { font-size: 1.95rem; }
  h2 { font-size: 1.32rem; }

  .site-header,
  .site-footer,
  .site-main > * {
    padding-left: 1rem;
    padding-right: 1rem;
  }
}