:root{
  --paper:#f7f8fa; --ink:#12151c; --ink-soft:#3a4150; --line:#dfe3ea;
  --substrate:#0d1017; --substrate-2:#151a25; --substrate-line:#232a39;
  --teal:#38d6be; --coral:#ff7c50; --rule:#6c5cff; --rule-dim:#8b7dff;
  --paper-dim:#6b7280;
  --serif:"Newsreader",Georgia,serif;
  --disp:"Space Grotesk",system-ui,sans-serif;
  --mono:"IBM Plex Mono",ui-monospace,monospace;
  --measure:42rem;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--paper);color:var(--ink);font-family:var(--serif);
  font-size:19px;line-height:1.65;font-optical-sizing:auto;
  -webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
.mono{font-family:var(--mono)}
b,strong{font-weight:600}
em{font-style:italic;color:var(--ink)}

/* ---------- masthead ---------- */
.masthead{max-width:var(--measure);margin:0 auto;padding:9vh 1.5rem 2.5rem}
.eyebrow{font-family:var(--mono);font-size:.72rem;letter-spacing:.22em;text-transform:uppercase;
  color:var(--rule);margin-bottom:1.4rem}
.eyebrow a{color:inherit;text-decoration:none}
.eyebrow a:hover{text-decoration:underline}
.masthead h1{font-family:var(--disp);font-weight:700;font-size:clamp(1.9rem,4.2vw,2.8rem);
  line-height:1.08;letter-spacing:-.02em;margin:.2rem 0 1.4rem}
.standfirst{font-size:1.22rem;line-height:1.55;color:var(--ink-soft)}
.standfirst b{color:var(--ink)}

/* ---------- demo (dark substrate hero) ---------- */
.demo{background:var(--substrate);color:#dfe4ee;margin:0 0 2.6rem;padding:1.8rem 1.5rem 3rem;
  border-bottom:1px solid var(--substrate-line)}
.demo-head{max-width:64rem;margin:0 auto 1.3rem;text-align:center}
.demo-head .eyebrow{margin-bottom:.5rem}
.demo-head h1{font-family:var(--disp);font-weight:700;color:#fff;white-space:nowrap;
  font-size:clamp(.95rem,4.7vw,2.4rem);letter-spacing:-.02em;line-height:1.12;margin:.15rem 0 0}
.demo-lead{color:#aab2c2;font-size:1.02rem;line-height:1.5;margin:0 0 1rem;max-width:40rem}
.nogpu-msg{max-width:var(--measure);margin:0 auto 1.5rem;background:var(--substrate-2);
  border:1px solid var(--substrate-line);border-radius:8px;padding:.9rem 1.1rem;color:#cdd4e0;font-size:.95rem}

.demo-grid{max-width:64rem;margin:0 auto;display:grid;grid-template-columns:1fr 280px;gap:1.6rem;align-items:start}
.substrate-label,.metric-cap,.digit-key{font-family:var(--mono);font-size:.68rem;letter-spacing:.1em;
  text-transform:uppercase;color:#7b8499}
.substrate-label{display:flex;justify-content:space-between;align-items:center;margin-bottom:.7rem}
.substrate-label span{display:flex;align-items:center;gap:.4rem;text-transform:none;letter-spacing:.04em}
.sw{width:12px;height:12px;border-radius:2px;display:inline-block}
.sw.teal{background:var(--teal)} .sw.coral{background:var(--coral)}

.layers{display:flex;align-items:flex-start;justify-content:center;gap:.35rem;flex-wrap:wrap;background:var(--substrate-2);
  border:1px solid var(--substrate-line);border-radius:12px;padding:1.1rem 1.1rem 1.3rem;min-height:260px}
.layer-fig{margin:0;display:flex;flex-direction:column;align-items:center;gap:.45rem;position:relative}
.layer-fig canvas{background:var(--substrate);border-radius:5px;image-rendering:pixelated;
  max-width:100%;height:auto;box-shadow:0 0 0 1px var(--substrate-line), 0 6px 18px rgba(0,0,0,.35)}
.layer-fig figcaption{font-family:var(--mono);font-size:.72rem;text-align:center;color:#8b94a8;line-height:1.4}
.layer-fig .lname{display:block;color:#b6bece}
.layer-fig .ldim{display:block;margin-top:.15rem;font-size:1rem;font-weight:600;color:#dbe0ea;letter-spacing:.01em}
.layer-fig .d-out.edit{color:var(--rule-dim)}   /* the slider-controlled dimension */
/* inline layer controls */
.layer-slider{max-width:100%;margin:.1rem 0 0;accent-color:var(--rule);cursor:pointer}
.layer-rm{position:absolute;top:-9px;right:-9px;width:26px;height:26px;border-radius:50%;padding:0;
  display:inline-flex;align-items:center;justify-content:center;
  border:1px solid #56617a;background:var(--substrate-2);color:#eef1f6;cursor:pointer;transition:.15s;box-shadow:0 2px 6px rgba(0,0,0,.45)}
.layer-rm svg{width:13px;height:13px}
.layer-rm:hover{border-color:var(--coral);background:var(--coral);color:#fff;transform:scale(1.08)}
/* insert-layer gaps: flow arrow + "+" button, vertically centered on the canvases */
.flow-gap{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:.55rem;min-height:260px}
.flow{display:inline-flex;align-items:center;justify-content:center;color:var(--rule);opacity:.75}
.flow svg{width:26px;height:26px}
.gap-add{width:27px;height:27px;border-radius:50%;padding:0;display:inline-flex;align-items:center;justify-content:center;
  border:1px solid #3f4a62;background:var(--substrate-2);color:var(--rule-dim);cursor:pointer;transition:.15s;box-shadow:0 1px 4px rgba(0,0,0,.35)}
.gap-add svg{width:14px;height:14px}
.gap-add:hover{border-color:var(--rule);background:var(--rule);color:#fff;transform:scale(1.1)}

.metrics{background:var(--substrate-2);border:1px solid var(--substrate-line);border-radius:12px;padding:1.2rem}
.metric-num{font-family:var(--disp);font-weight:700;font-size:2.8rem;line-height:1;color:#fff;letter-spacing:-.02em}
.metric-cap{margin-top:.3rem}
#acc-curve{width:100%;height:auto;margin:1rem 0 .4rem;display:block}
.metric-row{display:flex;justify-content:space-between;border-top:1px solid var(--substrate-line);
  padding-top:.8rem;margin-top:.4rem}
.metric-row span{font-size:1.1rem;color:#fff;display:block} .metric-row small{color:#7b8499;font-size:.7rem;font-family:var(--mono)}
.digits{display:grid;grid-template-columns:repeat(6,1fr);gap:4px;margin-top:1rem}
.digit{position:relative;border-radius:4px;overflow:hidden;aspect-ratio:1;background:#000}
.digit canvas{width:100%;height:100%;image-rendering:pixelated}
.digit .plabel{position:absolute;right:1px;bottom:0;font-family:var(--mono);font-size:.6rem;font-weight:500;
  padding:0 2px;border-radius:2px 0 0 0}
.digit.correct .plabel{background:var(--teal);color:#04140f}
.digit.wrong .plabel{background:var(--coral);color:#1a0a04}
.digit.correct{box-shadow:inset 0 0 0 1.5px var(--teal)}
.digit.wrong{box-shadow:inset 0 0 0 1.5px var(--coral)}
.digit-key{margin-top:.7rem;display:flex;align-items:center}
.dot{width:9px;height:9px;border-radius:2px;display:inline-block;margin:0 .3rem}
.dot.correct{background:var(--teal)} .dot.wrong{background:var(--coral)}

/* controls */
.controls{max-width:64rem;margin:1.6rem auto 0}
.ctl-main{display:flex;align-items:center;gap:.7rem;flex-wrap:wrap}
.btn{font-family:var(--disp);font-weight:500;font-size:.95rem;color:#dfe4ee;background:var(--substrate-2);
  border:1px solid var(--substrate-line);border-radius:8px;padding:.6rem 1.1rem;cursor:pointer;transition:.15s}
.btn:hover{border-color:var(--rule);color:#fff}
.btn.primary{background:var(--rule);border-color:var(--rule);color:#fff}
.btn.primary.on{background:transparent;color:var(--rule)}
.btn.primary:hover{filter:brightness(1.1)}
.speed{margin-left:auto;font-family:var(--mono);font-size:.78rem;color:#8b94a8;display:flex;align-items:center;gap:.5rem}
input[type=range]{accent-color:var(--rule)}
.speed #speed{width:130px;flex:none}                 /* fixed width so the value's length can't resize it */
.speed #speed-val{display:inline-block;min-width:6ch}

/* inline arch hint (below the weight field) */
.arch-hint{max-width:52rem;margin:.9rem auto 0;color:#8b94a8;font-size:.86rem;line-height:1.55;font-style:italic}
.arch-hint b{color:var(--rule-dim);font-style:normal;font-family:var(--mono);font-weight:600}
.arch-hint .archs{color:#dbe0ea}
.demo.nogpu .demo-grid,.demo.nogpu .controls{opacity:.35;pointer-events:none}

/* ---------- prose ---------- */
.prose{max-width:var(--measure);margin:0 auto;padding:0 1.5rem 6rem;position:relative}
.prose h2{font-family:var(--disp);font-weight:500;font-size:1.7rem;letter-spacing:-.01em;
  margin:3rem 0 .9rem;line-height:1.15}
.prose h3{font-family:var(--disp);font-weight:500;font-size:1.25rem;margin:2rem 0 .6rem;line-height:1.2}
.prose h4{font-family:var(--disp);font-weight:500;font-size:1.05rem;margin:1.6rem 0 .5rem;color:var(--ink)}
.prose p{margin:0 0 1.1rem}
.prose ul,.prose ol{margin:0 0 1.2rem;padding-left:1.3rem}
.prose li{margin:.4rem 0}
.prose a{color:var(--rule);text-decoration:underline;text-underline-offset:2px;text-decoration-thickness:1px}
/* forward / backward color-coding, matching the pipeline figure */
.fwd{color:var(--rule);font-weight:600}
.bwd{color:var(--coral);font-weight:600}
/* intro sits right under the demo: no giant bottom gap, tight heading above */
.prose.intro{padding-bottom:0}
.prose.intro h2{margin-top:.4rem}
/* figures + blockquotes in the article */
.prose figure{margin:1.8rem auto;text-align:center}
.prose figure img{max-width:100%;height:auto}
.prose figcaption{font-size:.9rem;color:var(--ink-soft);max-width:36rem;margin:.7rem auto 0;font-style:italic;line-height:1.5}
.prose blockquote{border-left:3px solid var(--rule);margin:1.5rem 0;padding:.3rem 0 .3rem 1.1rem;
  color:var(--ink-soft);font-style:italic}
/* wide figure: hangs equally off both sides of the reading column */
.prose .fig-wide{margin:1.8rem 0}
.prose .fig-wide img{display:block;max-width:min(64rem,calc(100vw - 3rem));margin-left:50%;transform:translateX(-50%)}

/* margin notes */
.margin-note{background:#eef0f6;border-left:3px solid var(--rule);border-radius:0 8px 8px 0;
  padding:1rem 1.2rem;margin:1.6rem 0;font-size:.96rem;color:var(--ink-soft)}
.margin-note h4{font-family:var(--disp);font-weight:500;font-size:.95rem;margin:0 0 .5rem;color:var(--ink)}
.margin-note p{margin:0}
.margin-note .opt{font-family:var(--mono);font-size:.6rem;text-transform:uppercase;letter-spacing:.1em;
  color:var(--rule);border:1px solid var(--rule);border-radius:3px;padding:1px 5px;margin-left:.4rem;vertical-align:middle}
@media(min-width:1180px){
  .margin-note{position:absolute;right:-20rem;width:17rem;margin:0;background:transparent;border-left:none;
    border-top:2px solid var(--rule);border-radius:0;padding:.8rem 0 0;font-size:.85rem}
}
mjx-container{font-size:.95em !important}

.colophon{background:var(--substrate);color:#aab2c2;margin-top:4rem;padding:2.4rem 1.5rem;
  border-top:1px solid var(--substrate-line);font-size:.85rem}
.colophon p{max-width:var(--measure);margin:0 auto}
.colophon a{color:var(--rule-dim)}
.colophon .mono{font-style:italic}

/* ---------- responsive ---------- */
@media(max-width:760px){
  body{font-size:17px}
  .demo-grid{grid-template-columns:1fr}
  .metrics{order:-1}
}
*:focus-visible{outline:2px solid var(--rule);outline-offset:2px;border-radius:3px}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto}}