/* ============================================================
   Material Design 3 system for the qwen3-bias article site.
   Roboto Flex for all chrome/UI/charts; Source Serif 4 for body prose.
   ============================================================ */
@font-face {
  font-family: "Roboto Flex"; font-style: normal; font-weight: 100 900;
  font-display: swap; src: url("fonts/roboto-flex-latin.woff2") format("woff2");
}
@font-face {
  font-family: "Source Serif 4"; font-style: normal; font-weight: 200 900;
  font-display: swap; src: url("fonts/source-serif-4-latin.woff2") format("woff2");
}
@font-face {
  font-family: "Source Serif 4"; font-style: italic; font-weight: 200 900;
  font-display: swap; src: url("fonts/source-serif-4-latin-italic.woff2") format("woff2");
}

/* -------- M3 color roles (light) -------- */
:root {
  --primary: #4B45C6; --on-primary: #FFFFFF;
  --primary-container: #E3DFFF; --on-primary-container: #100065;
  --secondary: #5D5C72; --on-secondary: #FFFFFF;
  --secondary-container: #E2E0F9; --on-secondary-container: #1A1A2C;
  --tertiary: #79536A; --tertiary-container: #FFD8EC; --on-tertiary-container: #2E1123;
  --error: #BA1A1A; --on-error: #FFFFFF; --error-container: #FFDAD6;
  --background: #FCF8FB; --on-background: #1C1B20;
  --surface: #FCF8FB; --on-surface: #1C1B20;
  --surface-variant: #E5E0EC; --on-surface-variant: #48454E;
  --surface-container-lowest: #FFFFFF;
  --surface-container-low: #F6F2F9;
  --surface-container: #F1ECF4;
  --surface-container-high: #EBE7EE;
  --surface-container-highest: #E5E1E9;
  --outline: #79767F; --outline-variant: #CAC5CF;
  --inverse-surface: #313036; --inverse-on-surface: #F3EFF4;
  --shadow: rgba(0,0,0,.14);

  /* categorical data palette (constant across themes; text-safe variants) */
  --qwen: #6C4AE0; --qwen-text: #6C4AE0;
  --mistral: #F2500F; --mistral-text: #C43F0A;
  --gemma: #4285F4; --gemma-text: #2D6CD8;
  --pos: #0E7A4D; --neg: #B42318; --hazard: #B45309;

  /* shape */
  --r-xs: 4px; --r-s: 8px; --r-m: 12px; --r-l: 16px; --r-xl: 28px; --r-full: 999px;
  /* elevation shadows */
  --e1: 0 1px 2px rgba(0,0,0,.10), 0 1px 3px 1px rgba(0,0,0,.06);
  --e2: 0 1px 2px rgba(0,0,0,.10), 0 2px 6px 2px rgba(0,0,0,.08);
  --e3: 0 4px 8px 3px rgba(0,0,0,.08), 0 1px 3px rgba(0,0,0,.12);

  --font: "Roboto Flex", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --font-serif: "Source Serif 4", Georgia, serif;
  --font-mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --measure: 690px; --rail: 232px;
}
:root[data-theme="dark"] { color-scheme: dark;
  --primary: #C5C0FF; --on-primary: #1B119A; --primary-container: #332DAE; --on-primary-container: #E3DFFF;
  --secondary: #C6C4DD; --on-secondary: #2F2F42; --secondary-container: #454459; --on-secondary-container: #E2E0F9;
  --tertiary: #E9B9D3; --tertiary-container: #5F3C52; --on-tertiary-container: #FFD8EC;
  --error: #FFB4AB; --on-error: #690005; --error-container: #93000A;
  --background: #141318; --on-background: #E6E1E9;
  --surface: #141318; --on-surface: #E6E1E9;
  --surface-variant: #48454E; --on-surface-variant: #CAC5CF;
  --surface-container-lowest: #0E0E13; --surface-container-low: #1C1B20;
  --surface-container: #211F24; --surface-container-high: #2B292F; --surface-container-highest: #36343A;
  --outline: #948F99; --outline-variant: #48454E;
  --inverse-surface: #E6E1E9; --inverse-on-surface: #313036;
  --mistral-text: #FF8A5C; --gemma-text: #7FB0FF;
  --pos: #4ED8A0; --neg: #F4A6A0; --hazard: #F0B060;
  --e1: 0 1px 3px rgba(0,0,0,.5); --e2: 0 2px 6px rgba(0,0,0,.55); --e3: 0 6px 14px rgba(0,0,0,.55);
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) { color-scheme: dark;
    --primary: #C5C0FF; --on-primary: #1B119A; --primary-container: #332DAE; --on-primary-container: #E3DFFF;
    --secondary: #C6C4DD; --on-secondary: #2F2F42; --secondary-container: #454459; --on-secondary-container: #E2E0F9;
    --tertiary: #E9B9D3; --tertiary-container: #5F3C52; --on-tertiary-container: #FFD8EC;
    --error: #FFB4AB; --on-error: #690005; --error-container: #93000A;
    --background: #141318; --on-background: #E6E1E9;
    --surface: #141318; --on-surface: #E6E1E9;
    --surface-variant: #48454E; --on-surface-variant: #CAC5CF;
    --surface-container-lowest: #0E0E13; --surface-container-low: #1C1B20;
    --surface-container: #211F24; --surface-container-high: #2B292F; --surface-container-highest: #36343A;
    --outline: #948F99; --outline-variant: #48454E;
    --inverse-surface: #E6E1E9; --inverse-on-surface: #313036;
    --mistral-text: #FF8A5C; --gemma-text: #7FB0FF;
    --pos: #4ED8A0; --neg: #F4A6A0; --hazard: #F0B060;
    --e1: 0 1px 3px rgba(0,0,0,.5); --e2: 0 2px 6px rgba(0,0,0,.55); --e3: 0 6px 14px rgba(0,0,0,.55);
  }
}

/* -------- reset -------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body { margin: 0; background: var(--background); color: var(--on-surface);
  font-family: var(--font); font-optical-sizing: auto; -webkit-font-smoothing: antialiased; }
img, svg { max-width: 100%; }
a { color: var(--primary); text-underline-offset: 2px; }
.skip { position: absolute; left: -999px; top: 8px; background: var(--primary); color: var(--on-primary);
  padding: 10px 16px; border-radius: var(--r-s); z-index: 80; font-weight: 600; }
.skip:focus { left: 12px; }
:focus-visible { outline: 3px solid var(--primary); outline-offset: 2px; border-radius: var(--r-xs); }

/* -------- M3 type scale -------- */
.display-l { font-size: clamp(2.4rem, 5.2vw, 3.5rem); line-height: 1.1; font-weight: 700; letter-spacing: -.02em; }
.headline-l { font-size: 2rem; line-height: 1.22; font-weight: 650; letter-spacing: -.01em; }
.headline-s { font-size: 1.5rem; line-height: 1.3; font-weight: 600; }
.title-l { font-size: 1.375rem; line-height: 1.35; font-weight: 600; }
.title-m { font-size: 1rem; line-height: 1.4; font-weight: 600; letter-spacing: .01em; }
.label-l { font-size: .875rem; font-weight: 600; letter-spacing: .02em; }
.label-m { font-size: .75rem; font-weight: 600; letter-spacing: .05em; }
.label-s { font-size: .6875rem; font-weight: 600; letter-spacing: .06em; text-transform: uppercase; }

/* -------- top app bar -------- */
.appbar { position: sticky; top: 0; z-index: 40; height: 60px; display: flex; align-items: center;
  gap: 12px; padding: 0 16px 0 20px; background: color-mix(in srgb, var(--surface) 86%, transparent);
  backdrop-filter: saturate(1.4) blur(10px); border-bottom: 1px solid var(--outline-variant); }
.appbar__title { font-weight: 600; font-size: .95rem; color: var(--on-surface); margin-right: auto;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.appbar__title b { color: var(--primary); }
.appbar__action { color: var(--primary); text-decoration: none; font-weight: 600; font-size: .82rem;
  padding: 8px 14px; border-radius: var(--r-full); border: 1px solid var(--outline); white-space: nowrap; }
.progress { position: absolute; inset: auto 0 0 0; height: 2px; background: transparent; }
.progress i { display: block; height: 100%; transform: scaleX(0); transform-origin: 0 50%;
  background: linear-gradient(90deg, var(--qwen), var(--mistral) 55%, var(--gemma)); }

/* M3 switch (theme) */
.switch { position: relative; width: 52px; height: 32px; border: 0; background: none; cursor: pointer;
  padding: 0; flex: none; }
.switch__track { display: block; width: 52px; height: 32px; border-radius: var(--r-full);
  background: var(--surface-container-highest); border: 2px solid var(--outline); transition: background .2s, border-color .2s; }
.switch__thumb { position: absolute; top: 8px; left: 8px; width: 16px; height: 16px; border-radius: 50%;
  background: var(--outline); transition: left .2s, width .2s, height .2s, background .2s, top .2s; }
.switch[aria-pressed="true"] .switch__track { background: var(--primary); border-color: var(--primary); }
.switch[aria-pressed="true"] .switch__thumb { left: 28px; top: 6px; width: 20px; height: 20px; background: var(--on-primary); }

/* -------- layout -------- */
.shell { max-width: 1160px; margin: 0 auto; padding: 0 24px; }
main { max-width: var(--measure); margin: 0 auto; }
@media (min-width: 1100px) {
  .shell { display: grid; grid-template-columns: var(--rail) minmax(0, var(--measure)); gap: 60px;
    justify-content: center; max-width: 1040px; }
  main { max-width: none; }
}

/* -------- navigation list (TOC) -------- */
.toc { display: none; }
@media (min-width: 1100px) {
  .toc { display: block; position: sticky; top: 84px; align-self: start; }
  .toc__kicker { color: var(--on-surface-variant); margin: 0 0 8px 16px; }
  .toc ol { list-style: none; margin: 0; padding: 0; }
  .toc__part { color: var(--on-surface-variant); margin: 16px 0 4px 16px; }
  .toc a { display: block; padding: 8px 16px; margin: 1px 0; color: var(--on-surface-variant);
    text-decoration: none; border-radius: var(--r-full); font-size: .875rem; position: relative; }
  .toc a::before { content: ""; position: absolute; inset: 0; border-radius: inherit; background: currentColor;
    opacity: 0; }
  .toc a:hover::before { opacity: .08; }
  .toc a[aria-current="true"] { color: var(--on-secondary-container); background: var(--secondary-container);
    font-weight: 600; }
}

/* -------- hero -------- */
.hero { padding: 64px 0 36px; }
.hero__kicker { color: var(--primary); margin: 0 0 18px; }
.hero h1 { margin: 0 0 22px; color: var(--on-surface); }
.hero__dek { font-family: var(--font-serif); font-size: 1.3rem; line-height: 1.5; color: var(--on-surface-variant);
  margin: 0 0 26px; max-width: 42ch; }
.badges { list-style: none; display: flex; flex-wrap: wrap; gap: 8px; margin: 0; padding: 0; }
.badges li { font-size: .78rem; font-weight: 600; padding: 7px 14px; border-radius: var(--r-s);
  background: var(--secondary-container); color: var(--on-secondary-container); }
.badges a { color: var(--on-primary-container); background: var(--primary-container); text-decoration: none;
  padding: 7px 14px; border-radius: var(--r-s); font-weight: 600; font-size: .78rem; }

/* -------- part header -------- */
.part { margin: 64px 0 8px; padding: 22px 24px; border-radius: var(--r-l);
  background: var(--primary-container); color: var(--on-primary-container); scroll-margin-top: 76px; }
.part__num { color: var(--primary); opacity: .85; margin: 0 0 6px; }
.part h2 { margin: 0 0 8px; color: var(--on-primary-container); }
.part p { margin: 0; font-family: var(--font-serif); font-size: 1.05rem; line-height: 1.5;
  color: color-mix(in srgb, var(--on-primary-container) 88%, transparent); }

/* -------- prose (serif body) -------- */
.prose { margin-bottom: 8px; }
.prose h3 { font-size: 1.5rem; line-height: 1.28; font-weight: 600; letter-spacing: -.005em;
  color: var(--on-surface); margin: 56px 0 18px; scroll-margin-top: 76px; }
.s-num { display: block; font-family: var(--font); font-size: .78rem; font-weight: 700; letter-spacing: .06em;
  color: var(--primary); margin-bottom: 8px; }
.prose p, .prose li { font-family: var(--font-serif); font-size: 1.18rem; line-height: 1.66; color: var(--on-surface); }
.prose p { margin: 0 0 20px; }
.prose ul { margin: 0 0 20px; padding-left: 1.1em; }
.prose li { margin: 0 0 13px; }
.prose code { font-family: var(--font-mono); font-size: .82em; background: var(--surface-container-high);
  padding: .1em .4em; border-radius: var(--r-xs); }
#intro { scroll-margin-top: 76px; }
blockquote { margin: 24px 0; padding: 16px 20px; border-radius: var(--r-m); background: var(--surface-container);
  font-family: var(--font-serif); font-style: italic;
  font-size: 1.2rem; line-height: 1.5; color: var(--on-surface); }

/* provenance stat */
.stat { border-bottom: 2px dotted var(--primary); cursor: help; font-style: normal; }
.tip { position: fixed; z-index: 90; max-width: 300px; background: var(--inverse-surface);
  color: var(--inverse-on-surface); font-family: var(--font); font-size: .8rem; line-height: 1.45;
  padding: 9px 12px; border-radius: var(--r-s); box-shadow: var(--e2); pointer-events: none;
  opacity: 0; transform: translateY(4px); transition: opacity .12s, transform .12s; }
.tip.show { opacity: 1; transform: translateY(0); }

/* -------- figure / chart container -------- */
.fig { margin: 30px 0; padding: 20px 20px 16px; border-radius: var(--r-l); background: var(--surface-container-low);
  border: 1px solid var(--outline-variant); }
.fig__title { color: var(--on-surface); margin: 0 0 2px; }
.fig__cap { color: var(--on-surface-variant); font-size: .82rem; line-height: 1.5; margin: 12px 0 0; }
.chart { width: 100%; }
.chart svg { width: 100%; height: auto; display: block; overflow: visible; }
.chart text { font-family: var(--font); fill: var(--on-surface-variant); }
.chart .grid { stroke: var(--outline-variant); stroke-width: 1; }
.chart .axis { stroke: var(--outline); stroke-width: 1; }
.chart .bar { rx: 4; cursor: pointer; transition: opacity .12s; }
.chart .bar:hover { opacity: .82; }
.chart .val { fill: var(--on-surface); font-weight: 600; }
.chart .lbl { fill: var(--on-surface-variant); }
.hint { font-size: .74rem; color: var(--on-surface-variant); margin: 10px 0 0; display: flex;
  align-items: center; gap: 6px; }
.hint::before { content: "↳"; color: var(--primary); font-weight: 700; }
.legend { display: flex; flex-wrap: wrap; gap: 14px; margin: 4px 0 12px; font-size: .78rem; font-weight: 600; }
.legend span { display: inline-flex; align-items: center; gap: 6px; color: var(--on-surface-variant); }
.legend i { width: 12px; height: 12px; border-radius: 3px; display: inline-block; }

/* -------- chips + segmented button -------- */
.chiprow { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 14px; }
.chip { font-family: var(--font); font-size: .82rem; font-weight: 600; padding: 7px 14px;
  border-radius: var(--r-s); border: 1px solid var(--outline); background: transparent; color: var(--on-surface-variant);
  cursor: pointer; display: inline-flex; align-items: center; gap: 8px; line-height: 1.2; position: relative; }
.chip::before { content: ""; position: absolute; inset: 0; border-radius: inherit; background: currentColor; opacity: 0; }
.chip:hover::before { opacity: .08; }
.chip[aria-selected="true"], .chip[aria-expanded="true"] { background: var(--secondary-container);
  color: var(--on-secondary-container); border-color: transparent; }
.chip__dot { width: 9px; height: 9px; border-radius: 50%; flex: none; }
.chip__dot.pro { background: var(--pos); } .chip__dot.critical { background: var(--neg); }
.chip__dot.neutral { background: var(--outline); }
.chip__dot.neutralcrit { background: linear-gradient(90deg, var(--outline) 50%, var(--neg) 50%); }
.chip__dot.distractor { background: transparent; border: 1.5px dashed var(--outline); }
.chip.is-hazard { background: var(--secondary-container); color: var(--on-secondary-container); }
.segmented { display: inline-flex; margin-bottom: 14px; border: 1px solid var(--outline); border-radius: var(--r-full);
  overflow: hidden; }
.segmented button { font-family: var(--font); font-size: .82rem; font-weight: 600; padding: 9px 16px; border: 0;
  background: transparent; color: var(--on-surface-variant); cursor: pointer; line-height: 1.2; position: relative; }
.segmented button + button { border-left: 1px solid var(--outline); }
.segmented button::before { content: ""; position: absolute; inset: 0; background: currentColor; opacity: 0; }
.segmented button:hover::before { opacity: .08; }
.segmented button[aria-pressed="true"] { background: var(--secondary-container); color: var(--on-secondary-container); }

/* -------- explorer + doc card -------- */
.explorer { margin: 30px 0; padding: 20px; border-radius: var(--r-l); background: var(--surface-container);
  border: 1px solid var(--outline-variant); scroll-margin-top: 76px; }
.explorer__title { color: var(--on-surface); margin: 0 0 4px; }
.explorer__intro { color: var(--on-surface-variant); font-size: .85rem; line-height: 1.5; margin: 0 0 16px; }
.explorer__mount { min-height: 440px; color: var(--on-surface-variant); font-size: .85rem; }
.explorer__task { font-size: .82rem; color: var(--on-surface-variant); margin: 0 0 14px; }
.explorer__task summary { cursor: pointer; color: var(--primary); font-weight: 600; }
.explorer__task p { margin: 8px 0 0; line-height: 1.5; }
.doc-card { background: var(--surface-container-lowest); border: 1px solid var(--outline-variant);
  border-radius: var(--r-m); padding: 22px 24px; box-shadow: var(--e1); }
.doc-card__flag { display: inline-block; font-family: var(--font); font-size: .68rem; font-weight: 700;
  letter-spacing: .05em; text-transform: uppercase; color: var(--on-secondary-container); background: var(--secondary-container);
  border-radius: var(--r-xs); padding: 3px 8px; margin-bottom: 12px; }
.doc-card__src { font-size: .68rem; font-weight: 600; letter-spacing: .06em; text-transform: uppercase; color: var(--on-surface-variant); }
.doc-card__rule { border: 0; border-top: 3px double var(--outline-variant); margin: 8px 0 14px; }
.doc-card__title { font-family: var(--font); font-weight: 600; font-size: 1.1rem; line-height: 1.3; margin: 0 0 12px; color: var(--on-surface); }
.doc-card[lang="fr"] .doc-card__body { hyphens: auto; }
.doc-card__body p { font-family: var(--font-serif); font-size: 1rem; line-height: 1.6; margin: 0 0 12px; color: var(--on-surface); }
.doc-card__meta { display: flex; flex-wrap: wrap; gap: 10px; align-items: center; margin-top: 16px;
  padding-top: 12px; border-top: 1px solid var(--outline-variant); font-family: var(--font-mono); font-size: .72rem; color: var(--on-surface-variant); }
.badge { font-family: var(--font); font-size: .66rem; font-weight: 600; letter-spacing: .04em; text-transform: uppercase;
  padding: 3px 8px; border-radius: var(--r-xs); border: 1px solid var(--outline-variant); }
.badge.pro { color: var(--pos); } .badge.critical { color: var(--neg); }
.badge.neutral { color: var(--on-surface-variant); } .badge.neutralcrit { color: var(--on-surface-variant); }

/* -------- verbatim / response cards -------- */
.model-qwen { --m: var(--qwen-text); } .model-mistral { --m: var(--mistral-text); } .model-gemma { --m: var(--gemma-text); }
.responses { display: grid; gap: 14px; margin: 26px 0; }
@media (min-width: 720px) { .responses.cols-3 { grid-template-columns: 1fr 1fr 1fr; } .responses.cols-2 { grid-template-columns: 1fr 1fr; } }
.resp { border: 1px solid var(--outline-variant); border-radius: var(--r-m); overflow: hidden;
  background: var(--surface-container-lowest); display: flex; flex-direction: column; }
.resp.highlight { animation: flash 1.4s ease; }
@keyframes flash { 0%,100% { box-shadow: var(--e1); } 30% { box-shadow: 0 0 0 3px var(--primary); } }
.resp__head { display: flex; align-items: center; gap: 8px; padding: 12px 15px; border-bottom: 1px solid var(--outline-variant); }
.resp__dot { width: 10px; height: 10px; border-radius: 50%; background: var(--m); flex: none; }
.resp__model { font-weight: 700; font-size: .85rem; color: var(--m); }
.resp__gloss { margin-left: auto; font-size: .68rem; font-weight: 600; letter-spacing: .03em; text-transform: uppercase;
  color: var(--on-surface-variant); text-align: right; }
.resp__q { font-size: .78rem; color: var(--on-surface-variant); padding: 10px 15px 0; font-style: italic; }
.resp__body { font-family: var(--font-serif); font-size: .98rem; line-height: 1.55; padding: 10px 15px 15px;
  color: var(--on-surface); white-space: pre-wrap; }
.resp__more { font-size: .78rem; color: var(--primary); background: none; border: 0; border-top: 1px solid var(--outline-variant);
  padding: 9px 15px; cursor: pointer; text-align: left; font-weight: 600; }
.resp__foot { font-size: .76rem; color: var(--on-surface-variant); padding: 10px 15px; border-top: 1px solid var(--outline-variant); background: var(--surface-container-low); }

/* -------- M3 data table -------- */
.m3-table-wrap { margin: 26px 0; overflow-x: auto; border: 1px solid var(--outline-variant); border-radius: var(--r-m); }
.m3-table { border-collapse: collapse; width: 100%; min-width: 640px; font-size: .82rem; }
.m3-table th, .m3-table td { text-align: left; padding: 12px 14px; border-bottom: 1px solid var(--outline-variant);
  vertical-align: top; line-height: 1.4; }
.m3-table th { font-weight: 600; color: var(--on-surface-variant); background: var(--surface-container); position: sticky; top: 0; }
.m3-table td:first-child { font-weight: 600; color: var(--on-surface); }
.m3-table tr:last-child td { border-bottom: 0; }

/* -------- entity grid (native chart) -------- */
.entgrid { display: flex; flex-direction: column; gap: 4px; font-size: .72rem; }
.entgrid__row { display: grid; grid-template-columns: 84px repeat(9, 1fr); gap: 4px; }
.entgrid__rk { font-weight: 600; color: var(--on-surface); display: flex; align-items: center; }
.entgrid__ck { color: var(--on-surface-variant); text-align: center; font-weight: 600; font-size: .64rem; padding-bottom: 2px; }
.entgrid__c { text-align: center; padding: 8px 2px; border-radius: var(--r-xs); background: var(--surface-container-high);
  color: var(--on-surface-variant); overflow: hidden; text-overflow: ellipsis; }
.entgrid__c.odd { background: var(--error-container); color: var(--on-surface); font-weight: 600; }
.topic-reveal:not(:empty) { margin-top: 12px; padding: 12px 14px; border-radius: var(--r-m);
  background: var(--surface-container-high); font-family: var(--font-serif);
  font-size: .95rem; line-height: 1.5; color: var(--on-surface); }
.topic-reveal .rk { font-family: var(--font); font-size: .68rem; font-weight: 700; letter-spacing: .05em;
  text-transform: uppercase; color: var(--primary); display: block; margin-bottom: 4px; }

/* -------- schematic (native) -------- */
.schematic { display: grid; gap: 14px; margin: 26px 0; }
@media (min-width: 640px) { .schematic.cols-3 { grid-template-columns: 1fr auto 1fr auto 1fr; align-items: stretch; } }
.sch-card { background: var(--surface-container-lowest); border: 1px solid var(--outline-variant); border-radius: var(--r-m);
  padding: 16px 18px; box-shadow: var(--e1); }
.sch-card__k { color: var(--primary); margin: 0 0 6px; }
.sch-card__t { font-weight: 600; font-size: 1rem; color: var(--on-surface); margin: 0 0 6px; }
.sch-card__d { font-size: .82rem; color: var(--on-surface-variant); line-height: 1.45; margin: 0; }
/* the planted card is distinguished by its text, not by a colored border */
.sch-arrow { display: grid; place-items: center; color: var(--outline); font-size: 1.4rem; }
@media (max-width: 639px) { .sch-arrow { transform: rotate(90deg); } }

/* -------- footer -------- */
.site-footer { margin: 72px 0 120px; padding: 24px; border-radius: var(--r-l); background: var(--surface-container);
  color: var(--on-surface-variant); }
.site-footer p { margin: 0 0 12px; font-size: .95rem; line-height: 1.55; }
.site-footer a { color: var(--primary); }
.site-footer code { font-family: var(--font-mono); font-size: .82em; }

/* -------- mobile TOC -------- */
.toc-mobile { position: fixed; left: 12px; right: 12px; bottom: 12px; z-index: 45; background: var(--surface-container-high);
  border: 1px solid var(--outline-variant); border-radius: var(--r-l); box-shadow: var(--e3); overflow: hidden; }
.toc-mobile summary { list-style: none; padding: 14px 18px; font-weight: 600; font-size: .85rem; cursor: pointer;
  display: flex; align-items: center; justify-content: space-between; color: var(--on-surface); }
.toc-mobile summary::-webkit-details-marker { display: none; }
.toc-mobile summary::after { content: "▲"; font-size: .6rem; color: var(--on-surface-variant); }
.toc-mobile[open] summary::after { content: "▼"; }
.toc-mobile ol { list-style: none; margin: 0; padding: 4px 0 8px; max-height: 48vh; overflow: auto; border-top: 1px solid var(--outline-variant); }
.toc-mobile a { display: block; padding: 9px 18px; color: var(--on-surface-variant); text-decoration: none; font-size: .85rem; }
.toc-mobile a[aria-current="true"] { color: var(--on-surface); font-weight: 600; }
@media (min-width: 1100px) { .toc-mobile { display: none; } }

/* -------- lightbox (schematic/figure zoom fallback) -------- */
.lightbox { border: 0; padding: 0; background: transparent; max-width: 96vw; max-height: 96vh; }
.lightbox::backdrop { background: rgba(0,0,0,.8); }

/* -------- responsive + motion -------- */
@media (max-width: 640px) {
  .prose p, .prose li { font-size: 1.06rem; }
  .prose h3 { font-size: 1.3rem; margin-top: 44px; }
  .hero { padding: 40px 0 28px; }
  .shell { padding: 0 16px; }
  .fig { padding: 16px 14px 12px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; animation: none !important; }
}

/* provisional/human-validation banner */
.banner { margin: 20px 0 0; padding: 12px 16px; border-radius: var(--r-m);
  background: var(--surface-container-high); color: var(--on-surface-variant);
  font-size: .84rem; line-height: 1.5; border: 1px solid var(--outline-variant); }
.banner b { color: var(--on-surface); }