:root {
  --ink: #151711;
  --paper: #efede6;
  --acid: #d9ff42;
  --blue: #80aaff;
  --orange: #ff6637;
  --line: rgba(21, 23, 17, .22);
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { background: var(--paper); color: var(--ink); font-family: Arial, Helvetica, sans-serif; margin: 0; }
a { color: inherit; }
button, input { font: inherit; }
.progress { background: transparent; height: 4px; left: 0; position: fixed; right: 0; top: 0; z-index: 20; }
.progress span { background: var(--orange); display: block; height: 100%; transform: scaleX(0); transform-origin: left; }
.topbar {
  align-items: center; background: rgba(239,237,230,.92); border-bottom: 1px solid var(--line);
  display: grid; grid-template-columns: 1fr 1fr 1fr; height: 64px; left: 0; padding: 0 2rem;
  position: sticky; right: 0; top: 0; z-index: 10; backdrop-filter: blur(12px);
}
.brand { align-items: center; background: var(--ink); border-radius: 50%; color: var(--paper); display: flex; font: italic 1rem Georgia,serif; height: 32px; justify-content: center; text-decoration: none; width: 32px; }
.back, .chapter-count, .eyebrow, .scroll-cue, .chapter-head > p, .chapter-head > span, .origin-note > span, .memory-controls span, .memory-controls small, .compute-core small, .memory-block, .memory-readout > span, .meters span, .architecture-picker, dt, .calculator label, legend, .weight-total span, .hardware-result span, .hardware-result em, .metric-grid article > span, .takeaway > span, .source-grid span, .next-link span {
  font-family: "SFMono-Regular", Consolas, monospace; letter-spacing: .07em; text-transform: uppercase;
}
.back { font-size: .69rem; justify-self: center; text-decoration: none; }
.chapter-count { font-size: .62rem; justify-self: end; }
.section-dark { background: var(--ink); color: var(--paper); }
.section-acid { background: var(--acid); }
.section-blue { background: var(--blue); }

.hero { min-height: calc(100vh - 64px); overflow: hidden; padding: clamp(4rem,8vw,8rem) 2rem 3rem; position: relative; }
.hero-copy { position: relative; z-index: 2; }
.eyebrow { font-size: .65rem; margin: 0 0 2rem; }
.hero h1 { font-size: clamp(4.6rem,11vw,10rem); font-weight: 500; letter-spacing: -.075em; line-height: .82; margin: 0; }
.hero h1 em { color: var(--acid); font-family: Georgia,serif; font-weight: 400; }
.lede { font-family: Georgia,serif; font-size: clamp(1.2rem,2vw,1.75rem); line-height: 1.25; margin: 3rem 0 0; max-width: 540px; }
.origin-note { border-left: 1px solid rgba(239,237,230,.35); margin: 4rem 0 0; max-width: 480px; padding-left: 1rem; }
.origin-note > span { color: var(--acid); font-size: .58rem; }
.origin-note p { font-size: .78rem; line-height: 1.45; margin: .55rem 0; opacity: .72; }
.origin-note a { font-size: .7rem; }
.hero-machine { bottom: 8%; height: 70%; position: absolute; right: -3%; width: 56%; }
.plate { border: 1px solid rgba(239,237,230,.55); position: absolute; }
.plate-label { font: .54rem "SFMono-Regular",Consolas,monospace; left: 1rem; letter-spacing: .08em; position: absolute; top: 1rem; }
.conventional { height: 43%; left: 0; top: 9%; transform: rotate(-5deg); width: 43%; }
.die-grid { display: grid; gap: 4px; grid-template-columns: repeat(3,1fr); inset: 20% 35% 20% 12%; position: absolute; }
.die-grid i { background: var(--orange); display: block; }
.off-chip { align-items: center; border: 1px solid currentColor; bottom: 18%; display: flex; font: .52rem monospace; height: 40%; justify-content: center; position: absolute; right: 7%; width: 20%; }
.moving-bit { animation: bitTravel 2.4s ease-in-out infinite; background: var(--acid); border-radius: 50%; height: 8px; left: 64%; position: absolute; top: 50%; width: 8px; }
@keyframes bitTravel { 0%,100% { transform: translateX(-30px); } 50% { transform: translateX(38px); } }
.versus { font: italic 2rem Georgia,serif; left: 38%; position: absolute; top: 46%; z-index: 2; }
.wafer-plate { aspect-ratio: 1; border-radius: 50%; bottom: 0; right: 6%; transform: rotate(8deg); width: 60%; }
.wafer-grid { display: grid; gap: 3px; grid-template-columns: repeat(6,1fr); inset: 14%; position: absolute; }
.wafer-grid i { background: var(--acid); display: block; opacity: .75; }
.scroll-cue { bottom: 2.2rem; font-size: .58rem; position: absolute; right: 2rem; text-decoration: none; }

.chapter { padding: clamp(5rem,9vw,9rem) 2rem; }
.chapter-head { display: grid; grid-template-columns: 4rem minmax(9rem,1fr) 3fr; margin-bottom: clamp(4rem,8vw,8rem); }
.chapter-head > span, .chapter-head > p { font-size: .62rem; margin: .6rem 0 0; }
.chapter-head h2 { font-family: Georgia,serif; font-size: clamp(3rem,6.6vw,6.6rem); font-weight: 400; letter-spacing: -.06em; line-height: .88; margin: 0; }
.chapter-head.compact { margin-bottom: 4rem; }
.two-col { display: grid; gap: 7vw; grid-template-columns: 1fr 1fr; }
.prose-grid { margin-left: 25%; }
.big-copy { font-family: Georgia,serif; font-size: clamp(1.7rem,3vw,3rem); letter-spacing: -.035em; line-height: 1.08; margin: 0; }
.prose-grid > div { max-width: 490px; }
.prose-grid > div p { line-height: 1.55; margin: 0 0 1.5rem; }
.narrow { max-width: 750px; }

.memory-lab { border: 1px solid var(--ink); display: grid; grid-template-columns: minmax(230px,1fr) 3fr; margin-top: 6rem; min-height: 580px; }
.memory-controls { border-right: 1px solid var(--ink); display: flex; flex-direction: column; }
.memory-button { background: transparent; border: 0; border-bottom: 1px solid var(--ink); color: inherit; cursor: pointer; display: grid; grid-template-columns: 2.3rem 1fr; min-height: 92px; padding: 1rem; text-align: left; }
.memory-button b { align-self: end; font-family: Georgia,serif; font-size: 1.2rem; font-weight: 400; }
.memory-button small { font-size: .52rem; grid-column: 2; opacity: .6; }
.memory-button span { font-size: .54rem; }
.memory-button.active { background: var(--orange); }
.memory-stage { overflow: hidden; padding: 3rem; position: relative; }
.compute-core { align-items: center; background: var(--ink); color: var(--paper); display: flex; flex-direction: column; height: 150px; justify-content: center; left: 8%; position: absolute; top: 22%; width: 150px; }
.compute-core span { font: 2rem Georgia,serif; }
.compute-core small { font-size: .52rem; margin-top: 1rem; }
.memory-track { border-top: 1px dashed var(--ink); left: calc(8% + 150px); position: absolute; right: 18%; top: calc(22% + 75px); }
.memory-track i { background: var(--orange); border-radius: 50%; display: block; height: 10px; position: absolute; top: -5px; transition: left .45s ease; width: 10px; }
.memory-block { align-items: center; border: 1px solid var(--ink); display: flex; height: 120px; justify-content: center; position: absolute; right: 8%; top: calc(22% + 15px); transition: width .4s ease; width: 110px; }
.memory-readout { border-top: 1px solid var(--ink); bottom: 3rem; left: 3rem; padding-top: 1rem; position: absolute; right: 3rem; }
.memory-readout > span { font-size: .55rem; }
.memory-readout strong { display: block; font: 1.7rem Georgia,serif; margin-top: .8rem; }
.memory-readout p { line-height: 1.45; max-width: 650px; }

.distance-section, .model-section, .sources { padding: clamp(5rem,9vw,9rem) 2rem; }
.distance-lab { border-top: 1px solid var(--ink); display: grid; grid-template-columns: 1fr 2fr; padding-top: 2rem; }
.distance-copy { padding-right: 2rem; }
.distance-copy label { display: flex; font: .62rem monospace; justify-content: space-between; margin-top: 3rem; text-transform: uppercase; }
input[type=range] { accent-color: var(--ink); cursor: pointer; width: 100%; }
#distanceExplanation { font-size: .82rem; line-height: 1.45; }
.distance-visual { align-items: center; display: flex; min-height: 330px; overflow: hidden; padding: 2rem; }
.distance-core, .distance-memory { align-items: center; border: 1px solid var(--ink); display: flex; font: .65rem monospace; height: 120px; justify-content: center; width: 120px; }
.distance-wire { align-items: center; border-top: 1px solid var(--ink); display: flex; flex: 1; justify-content: space-around; transition: flex-basis .25s ease; }
.distance-wire i { background: var(--ink); border-radius: 50%; height: 7px; width: 7px; }
.distance-wire b { border: 1px solid var(--ink); height: 13px; transform: rotate(45deg); width: 13px; }
.meters { border-top: 1px solid var(--ink); display: grid; grid-column: 1 / -1; grid-template-columns: repeat(3,1fr); margin-top: 1rem; }
.meters div { border-right: 1px solid var(--ink); display: flex; flex-direction: column; gap: 1rem; min-height: 110px; padding: 1rem; }
.meters span { font-size: .55rem; }
.meters b { font: 1.5rem Georgia,serif; }
.footnote { font-size: .64rem; line-height: 1.4; margin: 1.5rem 0 0 auto; max-width: 550px; }

.architecture-picker { border-bottom: 1px solid var(--ink); display: grid; grid-template-columns: repeat(4,1fr); }
.architecture-button { background: transparent; border: 0; border-left: 1px solid var(--ink); color: inherit; cursor: pointer; font-size: .6rem; padding: 1.4rem .8rem; text-transform: uppercase; }
.architecture-button:last-child { border-right: 1px solid var(--ink); }
.architecture-button.active { background: var(--ink); color: var(--paper); }
.architecture-card { border: 1px solid var(--ink); border-top: 0; display: grid; grid-template-columns: 1.3fr 1fr; min-height: 580px; }
.architecture-diagram { align-items: center; border-right: 1px solid var(--ink); display: flex; justify-content: center; min-height: 500px; padding: 4rem; }
.logic-block, .arch-memory { align-items: center; border: 1px solid var(--ink); display: flex; font: .7rem monospace; height: 150px; justify-content: center; transition: border-radius .3s,width .3s; width: 150px; }
.arch-link { border-top: 1px dashed var(--ink); display: flex; justify-content: space-around; width: 35%; }
.arch-link i { background: var(--orange); border-radius: 50%; height: 9px; margin-top: -5px; width: 9px; }
.architecture-diagram[data-kind=apple] .logic-block { border-radius: 35% 0 0 35%; width: 190px; }
.architecture-diagram[data-kind=apple] .arch-memory { border-radius: 0 35% 35% 0; margin-left: -1px; width: 190px; }
.architecture-diagram[data-kind=apple] .arch-link { display: none; }
.architecture-diagram[data-kind=nvidia] .arch-link { width: 12%; }
.architecture-diagram[data-kind=nvidia] .arch-memory { background: var(--orange); height: 190px; width: 110px; }
.architecture-diagram[data-kind=cerebras] .logic-block { border-radius: 50%; height: 330px; position: relative; width: 330px; }
.architecture-diagram[data-kind=cerebras] .logic-block::after { content: "COMPUTE + SRAM"; font: .6rem monospace; }
.architecture-diagram[data-kind=cerebras] .logic-block { font-size: 0; }
.architecture-diagram[data-kind=cerebras] .arch-link, .architecture-diagram[data-kind=cerebras] .arch-memory { display: none; }
.architecture-copy { padding: 4rem 3rem; }
.architecture-copy h3 { font: 2.6rem/1 Georgia,serif; letter-spacing: -.04em; margin: 0 0 2rem; }
.architecture-copy > p:not(.eyebrow) { line-height: 1.55; }
.architecture-copy dl { border-top: 1px solid var(--ink); margin-top: 3rem; }
.architecture-copy dl div { border-bottom: 1px solid var(--ink); display: grid; grid-template-columns: 1fr 2fr; padding: 1rem 0; }
.architecture-copy dt { font-size: .54rem; }
.architecture-copy dd { font: 1rem Georgia,serif; margin: 0; }
.history-note { background: var(--orange); display: grid; gap: 3rem; grid-template-columns: 1fr 2fr; margin-left: 25%; padding: 3rem; }
.history-note h3 { font: 2rem Georgia,serif; margin: 0; }
.history-note p { line-height: 1.55; margin: 0; }

.model-intro { margin-left: 25%; }
.model-intro > p:last-child { line-height: 1.55; }
.calculator { border: 1px solid var(--ink); display: grid; grid-template-columns: 1fr 1.4fr; margin-top: 5rem; }
.calculator-controls { border-right: 1px solid var(--ink); padding: 2rem; }
.calculator h3 { font: 2rem Georgia,serif; margin: 0 0 3rem; }
.calculator label { display: flex; font-size: .57rem; justify-content: space-between; }
.calculator fieldset { border: 0; border-top: 1px solid var(--ink); display: grid; grid-template-columns: repeat(3,1fr); margin: 3rem 0 0; padding: 1.5rem 0 0; }
.calculator legend { font-size: .57rem; padding: 0 0 1rem; }
.precision { background: transparent; border: 1px solid var(--ink); color: inherit; cursor: pointer; padding: .9rem; }
.precision.active { background: var(--ink); color: var(--blue); }
.calculator-results { display: grid; grid-template-columns: 1fr 1fr; }
.weight-total { border-bottom: 1px solid var(--ink); display: flex; flex-direction: column; grid-column: 1 / -1; padding: 2rem; }
.weight-total span { font-size: .56rem; }
.weight-total b { font: clamp(3rem,7vw,7rem) Georgia,serif; letter-spacing: -.06em; margin-top: 1rem; }
.hardware-result { border-right: 1px solid var(--ink); display: flex; flex-direction: column; padding: 2rem; }
.hardware-result span { font-size: .58rem; line-height: 1.5; }
.hardware-result span small { opacity: .65; }
.hardware-result b { font: 4rem Georgia,serif; margin-top: 2rem; }
.hardware-result em { font-size: .55rem; font-style: normal; }
.calculator-results > p { border-top: 1px solid var(--ink); font-size: .68rem; grid-column: 1 / -1; line-height: 1.45; margin: 0; padding: 1rem 2rem; }

.metric-grid { border: 1px solid var(--ink); display: grid; grid-template-columns: repeat(3,1fr); margin-top: 5rem; }
.metric-grid article { border-bottom: 1px solid var(--ink); border-right: 1px solid var(--ink); min-height: 240px; padding: 1.5rem; }
.metric-grid article:nth-child(3n) { border-right: 0; }
.metric-grid article:nth-child(n+4) { border-bottom: 0; }
.metric-grid article > span { font-size: .55rem; }
.metric-grid h3 { font: 2rem Georgia,serif; margin: 3rem 0 1rem; }
.metric-grid p { font-size: .82rem; line-height: 1.45; margin: 0; }
.takeaway { background: var(--ink); color: var(--paper); margin-top: 8rem; padding: clamp(3rem,7vw,7rem); }
.takeaway > span { color: var(--acid); font-size: .58rem; }
.takeaway h2 { font: clamp(3rem,6vw,6rem)/.93 Georgia,serif; letter-spacing: -.055em; max-width: 950px; }
.takeaway p { line-height: 1.55; margin-left: 50%; max-width: 560px; }

.sources .chapter-head { border-bottom: 1px solid rgba(239,237,230,.3); padding-bottom: 3rem; }
.source-grid { display: grid; grid-template-columns: 1fr 1fr; }
.source-grid a { border-bottom: 1px solid rgba(239,237,230,.3); display: grid; gap: .8rem; grid-template-columns: 1fr auto; min-height: 150px; padding: 1.5rem; text-decoration: none; }
.source-grid a:nth-child(odd) { border-right: 1px solid rgba(239,237,230,.3); }
.source-grid span { color: var(--acid); font-size: .54rem; grid-column: 1 / -1; }
.source-grid strong { font: 1.4rem Georgia,serif; max-width: 430px; }
.source-grid b { font-size: 1.3rem; font-weight: 400; }
.caveat { font-size: .7rem; line-height: 1.5; margin: 3rem 0 6rem auto; max-width: 660px; opacity: .65; }
.next-link { border-top: 1px solid rgba(239,237,230,.3); display: flex; flex-direction: column; padding-top: 2rem; text-decoration: none; }
.next-link span { color: var(--acid); font-size: .56rem; }
.next-link strong { font: clamp(2.3rem,5vw,5rem) Georgia,serif; margin-top: 1rem; }

@media (max-width: 850px) {
  .topbar { grid-template-columns: auto 1fr; padding: 0 1rem; }
  .back { justify-self: end; }
  .chapter-count { display: none; }
  .hero { min-height: 940px; padding: 5rem 1rem 2rem; }
  .hero h1 { font-size: clamp(4rem,20vw,7rem); }
  .hero-machine { bottom: 6%; height: 42%; right: -12%; width: 100%; }
  .scroll-cue { display: none; }
  .chapter, .distance-section, .model-section, .sources { padding: 5rem 1rem; }
  .chapter-head { grid-template-columns: 2.5rem 1fr; }
  .chapter-head h2 { grid-column: 1 / -1; margin-top: 2rem; }
  .prose-grid, .model-intro { margin-left: 0; }
  .two-col { grid-template-columns: 1fr; }
  .memory-lab { grid-template-columns: 1fr; }
  .memory-controls { border-bottom: 1px solid var(--ink); border-right: 0; display: grid; grid-template-columns: 1fr 1fr; }
  .memory-button { border-right: 1px solid var(--ink); }
  .memory-stage { min-height: 530px; padding: 1rem; }
  .compute-core { height: 110px; left: 5%; width: 110px; }
  .memory-track { left: calc(5% + 110px); right: 15%; top: calc(22% + 55px); }
  .memory-block { height: 90px; right: 4%; top: calc(22% + 10px); width: 80px; }
  .memory-readout { bottom: 1.5rem; left: 1.5rem; right: 1.5rem; }
  .distance-lab { grid-template-columns: 1fr; }
  .distance-copy { padding-right: 0; }
  .meters { grid-column: 1; }
  .distance-core, .distance-memory { height: 80px; width: 80px; }
  .architecture-picker { grid-template-columns: 1fr 1fr; }
  .architecture-button { border-bottom: 1px solid var(--ink); }
  .architecture-card { grid-template-columns: 1fr; }
  .architecture-diagram { border-bottom: 1px solid var(--ink); border-right: 0; min-height: 370px; padding: 2rem; }
  .architecture-diagram[data-kind=cerebras] .logic-block { height: 260px; width: 260px; }
  .architecture-copy { padding: 2.5rem 1.5rem; }
  .history-note { grid-template-columns: 1fr; margin-left: 0; padding: 2rem; }
  .calculator { grid-template-columns: 1fr; }
  .calculator-controls { border-bottom: 1px solid var(--ink); border-right: 0; }
  .metric-grid { grid-template-columns: 1fr 1fr; }
  .metric-grid article, .metric-grid article:nth-child(3n) { border-bottom: 1px solid var(--ink); border-right: 1px solid var(--ink); }
  .metric-grid article:nth-child(even) { border-right: 0; }
  .takeaway { margin-top: 5rem; }
  .takeaway p { margin-left: 0; }
  .source-grid { grid-template-columns: 1fr; }
  .source-grid a:nth-child(odd) { border-right: 0; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .moving-bit { animation: none; }
  *, *::before, *::after { transition-duration: .001ms !important; }
}