/* The making of gase: project site styles.
 *
 * One stylesheet, no build step. Colours are tokens on :root (dark by
 * default, light via prefers-color-scheme or the toggle). The page sits on a
 * 12-column grid; chapters use .chapter > .grid with the column helpers
 * below, so a new chapter can copy the markup of an existing one.
 */

@font-face {
  font-family: "Archivo";
  src: url("fonts/archivo.woff2") format("woff2");
  font-weight: 400 900;
  font-stretch: 100% 125%;
  font-display: swap;
}
@font-face {
  font-family: "Source Serif";
  src: url("fonts/source-serif-4.woff2") format("woff2");
  font-weight: 400 700;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: "Source Serif";
  src: url("fonts/source-serif-4-italic.woff2") format("woff2");
  font-weight: 400;
  font-style: italic;
  font-display: swap;
}
@font-face {
  font-family: "JetBrains Mono";
  src: url("fonts/jetbrains-mono.woff2") format("woff2");
  font-weight: 400 700;
  font-display: swap;
}

:root {
  color-scheme: dark;
  /* The console: black plastic, the red and gold of the 16-BIT lettering,
     the green of a CRT's phosphor. */
  --bg: #0d0c0b;
  --bg-2: #161412;
  --bg-3: #1f1c19;
  --ink: #ede6d9;
  --ink-2: #b3ab9e;
  --ink-3: #8d857a;
  --rule: #2e2a26;
  --rule-2: #48423b;
  --red: #f0473b;
  --red-ink: #ff6a5c;
  --gold: #dcae45;
  --phosphor: #9fe0a8;
  --plate: #050505;
  --sel: rgba(240, 71, 59, 0.35);

  --display: "Archivo", "Helvetica Neue", Arial, sans-serif;
  --serif: "Source Serif", "Iowan Old Style", Georgia, serif;
  --mono: "JetBrains Mono", ui-monospace, "SF Mono", Menlo, Consolas, monospace;

  --margin: clamp(16px, 4.4vw, 64px);
  --gutter: clamp(16px, 2vw, 32px);
  --max: 1400px;
  --measure: 38rem;
}
@media (prefers-color-scheme: light) {
  :root:not([data-theme="dark"]) {
    color-scheme: light;
    --bg: #f3eee4;
    --bg-2: #ebe4d7;
    --bg-3: #e2d9c9;
    --ink: #17130f;
    --ink-2: #4c453c;
    --ink-3: #6a6257;
    --rule: #d6ccbc;
    --rule-2: #b9ad9a;
    --red: #c8261c;
    --red-ink: #b3211a;
    --gold: #8a6510;
    --phosphor: #1d6a37;
    --plate: #0d0c0b;
    --sel: rgba(200, 38, 28, 0.22);
  }
}
:root[data-theme="light"] {
  color-scheme: light;
  --bg: #f3eee4;
  --bg-2: #ebe4d7;
  --bg-3: #e2d9c9;
  --ink: #17130f;
  --ink-2: #4c453c;
  --ink-3: #6a6257;
  --rule: #d6ccbc;
  --rule-2: #b9ad9a;
  --red: #c8261c;
  --red-ink: #b3211a;
  --gold: #8a6510;
  --phosphor: #1d6a37;
  --plate: #0d0c0b;
  --sel: rgba(200, 38, 28, 0.22);
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; text-size-adjust: 100%; scroll-padding-top: 72px; }
@media (prefers-reduced-motion: no-preference) { html { scroll-behavior: smooth; } }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--serif);
  font-size: clamp(1.0625rem, 0.98rem + 0.3vw, 1.1875rem);
  line-height: 1.62;
  font-optical-sizing: auto;
  font-kerning: normal;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}
::selection { background: var(--sel); }
img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration-color: var(--red); text-decoration-thickness: 1px; text-underline-offset: 0.18em; }
a:hover { color: var(--red-ink); }
:focus-visible { outline: 2px solid var(--gold); outline-offset: 3px; }
code, kbd, samp { font-family: var(--mono); font-size: 0.84em; }
p code, li code, td code, figcaption code, dd code {
  padding: 0.05em 0.3em;
  background: var(--bg-2);
  border: 1px solid var(--rule);
  border-radius: 2px;
  white-space: nowrap;
}
kbd { border: 1px solid var(--rule-2); border-bottom-width: 2px; padding: 0 0.35em; border-radius: 2px; }
strong { font-weight: 650; }
.skip { position: absolute; left: -9999px; top: 0; z-index: 100; background: var(--ink); color: var(--bg); padding: 0.6rem 1rem; font-family: var(--display); }
.skip:focus { left: var(--margin); }
.visually-hidden { position: absolute !important; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }

/* ---------------------------------------------------------------- grid */
.grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  column-gap: var(--gutter);
  max-width: calc(var(--max) + 2 * var(--margin));
  margin-inline: auto;
  padding-inline: var(--margin);
}
.grid > * { grid-column: 1 / -1; min-width: 0; }
@media (min-width: 900px) {
  .c-full { grid-column: 1 / -1; }
  .c-text { grid-column: 4 / span 6; }
  .c-wide { grid-column: 4 / -1; }
  .c-side { grid-column: 10 / -1; }
  .c-lede { grid-column: 4 / span 8; }
  .c-left { grid-column: 1 / span 3; }
  .c-fig { grid-column: 2 / span 10; }
  .c-half-a { grid-column: 1 / span 6; }
  .c-half-b { grid-column: 7 / span 6; }
}
@media (min-width: 1200px) {
  .c-text { grid-column: 4 / span 5; }
  .c-side { grid-column: 10 / span 3; }
}

/* ---------------------------------------------------------------- masthead */
.masthead {
  position: sticky; top: 0; z-index: 20;
  background: color-mix(in srgb, var(--bg) 92%, transparent);
  -webkit-backdrop-filter: saturate(1.2);
  border-bottom: 1px solid var(--rule);
}
.masthead .grid { align-items: center; height: 52px; }
.masthead .brand { grid-column: 1 / span 4; font-family: var(--display); font-weight: 800; font-stretch: 125%; letter-spacing: 0.02em; text-decoration: none; font-size: 1.05rem; }
.masthead .brand span { color: var(--red); }
.masthead .where { display: none; }
.masthead .tools { grid-column: 5 / -1; justify-self: end; display: flex; gap: 1.25rem; align-items: center; font-family: var(--display); font-size: 0.82rem; letter-spacing: 0.04em; text-transform: uppercase; }
.masthead .tools a { text-decoration: none; }
@media (min-width: 900px) {
  .masthead .brand { grid-column: 1 / span 3; }
  .masthead .where { display: block; grid-column: 4 / span 6; font-family: var(--mono); font-size: 0.75rem; color: var(--ink-3); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
  .masthead .where b { color: var(--ink); font-weight: 500; }
  .masthead .tools { grid-column: 10 / -1; }
}
.theme-toggle {
  appearance: none; background: none; border: 1px solid var(--rule-2); color: var(--ink);
  font: inherit; text-transform: inherit; letter-spacing: inherit; padding: 0.3rem 0.6rem; border-radius: 0; cursor: pointer;
}
.theme-toggle:hover { border-color: var(--ink); }
.progress { position: absolute; left: 0; bottom: -1px; height: 2px; width: 100%; background: var(--red); transform-origin: 0 50%; transform: scaleX(var(--p, 0)); }

/* ---------------------------------------------------------------- hero */
.hero { padding-top: clamp(2.5rem, 7vw, 6rem); }
.kicker, .label {
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-3);
}
.hero .kicker { display: flex; gap: 1.2rem; flex-wrap: wrap; border-top: 1px solid var(--ink); padding-top: 0.8rem; }
.hero .kicker span:first-child { color: var(--gold); }
.hero h1 {
  font-family: var(--display);
  font-weight: 900;
  font-stretch: 125%;
  font-size: clamp(3.1rem, 11.5vw, 12.5rem);
  line-height: 0.86;
  letter-spacing: -0.035em;
  margin: clamp(1.5rem, 4vw, 3rem) 0 0;
  text-wrap: balance;
}
.hero h1 .dot { color: var(--red); }
.hero .standfirst {
  margin-top: clamp(1.5rem, 4vw, 3.5rem);
  font-size: clamp(1.25rem, 1rem + 1vw, 1.75rem);
  line-height: 1.38;
  font-style: italic;
  color: var(--ink);
  max-width: 34ch;
}
.hero .standfirst em { font-style: normal; }
.hero .byline { margin-top: 1.5rem; color: var(--ink-3); font-family: var(--mono); font-size: 0.78rem; letter-spacing: 0.02em; align-self: end; }
@media (min-width: 900px) {
  .hero .standfirst { grid-column: 4 / span 6; }
  .hero .byline { grid-column: 10 / -1; text-align: right; }
}
.hero-plate { margin-top: clamp(2.5rem, 6vw, 5rem); }

/* A screen: the emulator's picture, scaled by whole numbers only. */
.screen {
  --k: 1;
  margin: 0;
  justify-self: start;
}
.screen .crt {
  background: var(--plate);
  padding: clamp(8px, 1.2vw, 18px);
  display: inline-block;
  line-height: 0;
}
.screen img {
  width: calc(320px * var(--k));
  height: auto;
  image-rendering: pixelated;
  image-rendering: crisp-edges;
}
@media (min-width: 720px) { .screen.k2, .screen.k3 { --k: 2; } }
@media (min-width: 1100px) { .screen.k3 { --k: 3; } }
@media (max-width: 380px) { .screen img { width: 100%; } }
figcaption, .caption {
  font-family: var(--display);
  font-size: 0.82rem;
  line-height: 1.45;
  color: var(--ink-2);
  margin-top: 0.75rem;
  max-width: 62ch;
}
figcaption b, .caption b { color: var(--ink); font-weight: 650; }
figcaption .fig-no { font-family: var(--mono); color: var(--gold); margin-right: 0.6em; font-size: 0.72rem; letter-spacing: 0.06em; }

.hero-plate .screen { grid-column: 1 / -1; }
@media (min-width: 900px) {
  .hero-plate .screen { grid-column: 1 / span 9; }
  .hero-plate .facts { grid-column: 10 / -1; align-self: end; }
}
.facts { margin: 1.5rem 0 0; padding: 0; list-style: none; border-top: 1px solid var(--rule-2); }
.facts li { display: grid; grid-template-columns: 1fr auto; gap: 1rem; padding: 0.55rem 0; border-bottom: 1px solid var(--rule); font-family: var(--display); font-size: 0.86rem; color: var(--ink-2); }
.facts li b { font-weight: 700; color: var(--ink); font-variant-numeric: tabular-nums; text-align: right; }

/* ---------------------------------------------------------------- contents */
.contents { margin-top: clamp(4rem, 9vw, 8rem); }
.contents h2 { font-family: var(--mono); font-weight: 400; font-size: 0.75rem; letter-spacing: 0.08em; text-transform: uppercase; color: var(--ink-3); margin: 0 0 1rem; border-top: 1px solid var(--ink); padding-top: 0.8rem; }
.toc { list-style: none; margin: 0; padding: 0; columns: 1; column-gap: var(--gutter); }
@media (min-width: 760px) { .toc { columns: 2; } }
@media (min-width: 1200px) { .toc { columns: 3; } }
.toc li { break-inside: avoid; border-bottom: 1px solid var(--rule); }
.toc a { display: grid; grid-template-columns: 2.6rem 1fr; gap: 0.2rem 0.6rem; padding: 0.8rem 0 0.9rem; text-decoration: none; }
.toc .n { font-family: var(--mono); font-size: 0.78rem; color: var(--red-ink); padding-top: 0.25rem; }
.toc .t { font-family: var(--display); font-weight: 700; font-stretch: 112%; font-size: 1.12rem; line-height: 1.2; }
.toc .d { grid-column: 2; color: var(--ink-2); font-size: 0.95rem; line-height: 1.4; }
.toc a:hover .t { color: var(--red-ink); }
.toc .upcoming .n::after { content: " ·"; }

/* ---------------------------------------------------------------- chapters */
.chapter { padding-top: clamp(5rem, 11vw, 10rem); }
.chapter-head { row-gap: 0; }
.chapter-head .rule { border-top: 1px solid var(--ink); display: flex; justify-content: space-between; gap: 1rem; padding-top: 0.8rem; }
.chapter-head .num {
  font-family: var(--display);
  font-weight: 300;
  font-stretch: 100%;
  font-size: clamp(4.5rem, 11vw, 10rem);
  line-height: 0.8;
  color: var(--red);
  letter-spacing: -0.04em;
  margin-top: clamp(1rem, 2.5vw, 2rem);
  font-variant-numeric: tabular-nums;
}
.chapter-head h2 {
  font-family: var(--display);
  font-weight: 800;
  font-stretch: 125%;
  font-size: clamp(2.2rem, 5.6vw, 5.4rem);
  line-height: 0.95;
  letter-spacing: -0.03em;
  margin: clamp(1rem, 2.5vw, 2rem) 0 0;
  text-wrap: balance;
}
.chapter-head .dek {
  font-style: italic;
  font-size: clamp(1.2rem, 1rem + 0.7vw, 1.55rem);
  line-height: 1.38;
  color: var(--ink-2);
  margin: clamp(1.2rem, 2.5vw, 2rem) 0 0;
  max-width: 40ch;
}
@media (min-width: 900px) {
  .chapter-head .num { grid-column: 1 / span 3; grid-row: 2 / span 2; }
  .chapter-head h2 { grid-column: 4 / -1; }
  .chapter-head .dek { grid-column: 4 / span 7; }
}
.chapter-body { margin-top: clamp(2rem, 4vw, 3.5rem); align-items: start; }
.prose > * + * { margin-top: 1.05em; }
.prose p, .prose ul, .prose ol { margin-block: 0; }
.prose p + p { margin-top: 1.05em; }
.prose ul, .prose ol { padding-left: 1.2em; }
.prose li + li { margin-top: 0.4em; }
.prose li::marker { color: var(--red); }
.prose h3 {
  font-family: var(--display);
  font-weight: 700;
  font-stretch: 112%;
  font-size: 1.32rem;
  line-height: 1.2;
  margin: 2.2em 0 0;
}
.prose h3 + p { margin-top: 0.5em; }
.dropcap::first-letter {
  font-family: var(--display);
  font-weight: 900;
  font-stretch: 125%;
  float: left;
  font-size: 4.3em;
  line-height: 0.78;
  margin: 0.08em 0.1em 0 0;
  color: var(--red);
}

/* Marginalia: notes and numbers beside the text. */
.side { font-family: var(--display); font-size: 0.86rem; line-height: 1.5; color: var(--ink-2); margin-top: 2rem; }
.side > * + * { margin-top: 1.6rem; }
@media (min-width: 900px) { .side { margin-top: 0.3rem; } }
.side p { margin: 0; }
.side .note { border-top: 1px solid var(--rule-2); padding-top: 0.6rem; }
.side .note .label { display: block; margin-bottom: 0.35rem; }
.bignum { border-top: 1px solid var(--rule-2); padding-top: 0.6rem; }
.bignum b {
  display: block;
  font-family: var(--display);
  font-weight: 800;
  font-stretch: 125%;
  font-size: clamp(2.2rem, 3.6vw, 3.2rem);
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--ink);
  font-variant-numeric: tabular-nums;
}
.bignum b small { font-size: 0.45em; letter-spacing: 0; color: var(--ink-3); font-weight: 700; }
.bignum span { display: block; margin-top: 0.4rem; }

/* Pull quote */
.pull {
  font-family: var(--display);
  font-weight: 800;
  font-stretch: 118%;
  font-size: clamp(1.7rem, 3.4vw, 3rem);
  line-height: 1.04;
  letter-spacing: -0.02em;
  margin: clamp(2.5rem, 6vw, 5rem) 0;
  text-wrap: balance;
}
.pull::before { content: ""; display: block; width: 3rem; height: 4px; background: var(--red); margin-bottom: 1.2rem; }

/* Figures */
.figure { margin: clamp(2.5rem, 5vw, 4.5rem) 0 0; }
.figure + .figure { margin-top: clamp(2rem, 4vw, 3rem); }
.plate { background: var(--bg-2); border-top: 1px solid var(--rule-2); padding: clamp(16px, 2.5vw, 32px); }
.scroll-x { overflow-x: auto; -webkit-overflow-scrolling: touch; position: relative; }
.scroll-x > svg { min-width: 760px; }
.scroll-hint { display: none; }
@media (max-width: 700px) { .chart-scroll > svg { min-width: 640px; } }
@media (min-width: 701px) { .chart-scroll > svg { min-width: 0; } }
td code { white-space: normal; overflow-wrap: anywhere; }
@media (max-width: 800px) { .scroll-hint { display: block; } }

pre, .code {
  font-variant-ligatures: none;
  font-family: var(--mono);
  font-size: clamp(0.72rem, 0.68rem + 0.2vw, 0.84rem);
  line-height: 1.6;
  background: var(--plate);
  color: #d9d4c7;
  padding: clamp(14px, 2vw, 24px);
  margin: 0;
  overflow-x: auto;
  tab-size: 4;
}
pre .c { color: #7f786d; }
pre .k { color: #ff8a7e; }
pre .s { color: #e4bf63; }
pre .g { color: #9fe0a8; }
pre mark { background: rgba(240, 71, 59, 0.28); color: #fff; outline: 1px solid rgba(240, 71, 59, 0.7); }
pre .hot { color: #fff; background: rgba(240, 71, 59, 0.3); display: inline-block; width: 100%; }
pre .dim { color: #6f685e; }

/* Tables */
/* position: relative makes the scrolling box the containing block of the
   absolutely positioned bar marks inside its table, so they scroll with it
   instead of widening the page on phones. */
.table-wrap { overflow-x: auto; position: relative; }
table { border-collapse: collapse; width: 100%; font-family: var(--display); font-size: 0.88rem; font-variant-numeric: tabular-nums; }
caption { text-align: left; caption-side: bottom; font-size: 0.8rem; color: var(--ink-3); padding-top: 0.7rem; }
th, td { text-align: left; padding: 0.6rem 0.9rem 0.6rem 0; border-bottom: 1px solid var(--rule); vertical-align: top; }
thead th { font-family: var(--mono); font-weight: 400; font-size: 0.7rem; letter-spacing: 0.07em; text-transform: uppercase; color: var(--ink-3); border-bottom: 1px solid var(--ink); }
td.r, th.r { text-align: right; }
td.em { color: var(--red-ink); font-weight: 700; }
tbody th { font-weight: 650; }

/* ---------------------------------------------------------------- machine diagram */
.machine svg { width: 100%; height: auto; font-family: var(--mono); }
.machine .bus { stroke: var(--ink); stroke-width: 3; fill: none; }
.machine .bus-label { fill: var(--ink-3); font-size: 12px; letter-spacing: 0.08em; }
.machine .wire { stroke: var(--ink-2); stroke-width: 1.5; fill: none; }
.machine .clock { stroke: var(--gold); stroke-width: 1.5; stroke-dasharray: 5 4; fill: none; }
.machine .clock-label { fill: var(--gold); font-size: 13px; }
.machine .chip rect.body { fill: var(--bg); stroke: var(--ink); stroke-width: 1.5; transition: fill 0.2s, stroke 0.2s; }
.machine .chip .pin { stroke: var(--ink-3); stroke-width: 1; }
.machine .chip text { fill: var(--ink); }
.machine .chip .name { font-family: var(--display); font-weight: 800; font-stretch: 112%; font-size: 22px; }
.machine .chip .sub { font-size: 12.5px; fill: var(--ink-2); }
.machine .chip .crate { font-size: 12px; fill: var(--red-ink); }
.machine .mem rect.body { fill: var(--bg-2); stroke: var(--rule-2); }
.machine .mem .name { font-size: 16px; }
.machine .chip { cursor: pointer; outline: none; }
.machine .chip:hover rect.body, .machine .chip:focus-visible rect.body, .machine .chip.on rect.body { fill: var(--bg-3); stroke: var(--red); stroke-width: 2.5; }
.machine .chip:focus-visible rect.body { stroke: var(--gold); }
.machine .out { fill: var(--ink-3); font-size: 12px; letter-spacing: 0.06em; }
.machine .arrow { fill: var(--ink-2); }
.parts { list-style: none; margin: 0; padding: 0; display: grid; gap: 0 var(--gutter); grid-template-columns: 1fr; }
@media (min-width: 700px) { .parts { grid-template-columns: 1fr 1fr; } }
@media (min-width: 1100px) { .parts { grid-template-columns: repeat(3, 1fr); } }
.parts li { border-top: 1px solid var(--rule-2); padding: 0.8rem 0 1.2rem; transition: border-color 0.2s; }
.parts li.on { border-top-color: var(--red); }
.parts h4 { margin: 0; font-family: var(--display); font-weight: 750; font-stretch: 112%; font-size: 1.05rem; }
.parts h4 small { font-family: var(--mono); font-weight: 400; font-size: 0.7rem; color: var(--red-ink); margin-left: 0.5em; letter-spacing: 0.02em; }
.parts p { margin: 0.35rem 0 0; font-size: 0.95rem; line-height: 1.5; color: var(--ink-2); }

/* ---------------------------------------------------------------- crates */
.crates { margin-top: 0; }
.crates td:first-child, .crates th:first-child { white-space: nowrap; }
.crates code { white-space: nowrap; }
.bar-cell { width: 34%; min-width: 120px; }
.bar { position: relative; height: 10px; margin-top: 0.45em; }
.bar i { position: absolute; top: 0; bottom: 0; left: 0; background: var(--ink-2); border-radius: 0 2px 2px 0; }
.bar i.est { background: transparent; border: 1px dashed var(--ink-3); border-left: 0; top: -3px; bottom: -3px; }
.bar i.act { background: var(--red); }
.legend { display: flex; gap: 1.4rem; flex-wrap: wrap; font-family: var(--display); font-size: 0.8rem; color: var(--ink-2); margin-bottom: 0.8rem; align-items: center; }
.legend i { display: inline-block; width: 22px; height: 10px; vertical-align: -1px; margin-right: 0.45em; }
.legend i.act { background: var(--red); }
.legend i.est { border: 1px dashed var(--ink-3); }
.legend i.before { width: 10px; height: 10px; border-radius: 50%; border: 2px solid var(--ink-3); }
.legend i.after { width: 10px; height: 10px; border-radius: 50%; background: var(--red); }

/* ---------------------------------------------------------------- charts (inline SVG) */
.chart svg { width: 100%; height: auto; overflow: visible; font-family: var(--display); }
.chart .axis { stroke: var(--rule-2); stroke-width: 1; }
.chart .grid-line { stroke: var(--rule); stroke-width: 1; }
.chart .tick { fill: var(--ink-3); font-size: 12px; font-family: var(--mono); }
.chart .lab { fill: var(--ink); font-size: 14px; }
.chart .lab-2 { fill: var(--ink-2); font-size: 13px; }
.chart .val { fill: var(--ink); font-size: 13px; font-variant-numeric: tabular-nums; font-weight: 600; }
.chart .val-2 { fill: var(--ink-3); font-size: 13px; font-variant-numeric: tabular-nums; }
.chart .em { fill: var(--red-ink); font-weight: 700; }
.chart .m-ink { fill: var(--ink-2); }
.chart .m-red { fill: var(--red); }
.chart .m-gold { fill: var(--gold); }
.chart .m-hatch { fill: url(#hatch); }
.chart .stem { stroke: var(--rule-2); stroke-width: 2; }
.chart .dot-before { fill: var(--bg-2); stroke: var(--ink-3); stroke-width: 2; }
.chart .dot-after { fill: var(--red); stroke: var(--bg-2); stroke-width: 2; }
.chart .hit { fill: transparent; }
.chart .hit:hover + .shown, .chart g.row:hover .m-ink { fill: var(--ink); }
.chart g.row:hover .lab-2 { fill: var(--ink); }

/* Slots: one scanline drawn to scale */
.slots svg { width: 100%; height: auto; font-family: var(--mono); }
.slots .band { fill: var(--bg-3); }
.slots .t-act { stroke: var(--red); stroke-width: 3; }
.slots .t-blank { stroke: var(--ink-2); stroke-width: 1.2; }
.slots .base { stroke: var(--ink-3); stroke-width: 1; }
.slots text { fill: var(--ink-2); font-size: 13px; }
.slots .big { fill: var(--ink); font-family: var(--display); font-weight: 800; font-stretch: 112%; font-size: 20px; }

/* ---------------------------------------------------------------- layers */
.layers { --k: 1; }
.layers .controls { border: 0; border-top: 1px solid var(--rule-2); padding: 0.9rem 0 0; display: flex; flex-wrap: wrap; gap: 0.4rem 1.4rem; margin-bottom: 1.2rem; font-family: var(--display); font-size: 0.86rem; }
.layers .controls label { display: inline-flex; gap: 0.45rem; align-items: center; cursor: pointer; user-select: none; }
.layers input[type="checkbox"] { accent-color: var(--red); width: 1rem; height: 1rem; margin: 0; }
.layers .controls .sep { width: 1px; background: var(--rule-2); align-self: stretch; }
.stage { perspective: 1800px; perspective-origin: 50% 20%; padding: 0; }
.stack {
  position: relative;
  width: calc(320px * var(--k));
  aspect-ratio: 320 / 224;
  transform-style: preserve-3d;
  transition: transform 0.9s cubic-bezier(.2,.7,.1,1);
  margin-inline: auto;
}
.stack img, .stack .backdrop {
  position: absolute; inset: 0; width: 100%; height: 100%;
  image-rendering: pixelated; image-rendering: crisp-edges;
  transition: transform 0.9s cubic-bezier(.2,.7,.1,1), opacity 0.3s;
}
.stack .backdrop { background: #000; }
.stack-key { list-style: none; margin: 1rem 0 0; padding: 0; display: flex; flex-wrap: wrap; gap: 0.3rem 1.6rem; font-family: var(--display); font-size: 0.82rem; color: var(--ink-2); }
.stack-key b { color: var(--ink); font-weight: 650; margin-right: 0.35em; }
.stack-key li::before { content: "↑ "; color: var(--red); font-family: var(--mono); }
.stack-key li:last-child::before { content: "— "; }
.stack .layer { position: absolute; inset: 0; transition: transform 0.9s cubic-bezier(.2,.7,.1,1), opacity 0.3s; transform-style: preserve-3d; }
.stack .layer.edge::after { content: ""; position: absolute; inset: 0; outline: 1px solid var(--rule-2); opacity: 0; transition: opacity 0.4s; pointer-events: none; }
@media (min-width: 720px) { .layers { --k: 2; } }
.layers:has(#explode:checked) .stack { transform: rotateX(54deg) rotateZ(-32deg) scale(0.86); }
.layers:has(#explode:checked) .layer.edge::after { opacity: 1; }
.layers:has(#explode:checked) .l-backdrop { transform: translateZ(0); }
.layers:has(#explode:checked) .l-b { transform: translateZ(calc(42px * var(--k))); }
.layers:has(#explode:checked) .l-a { transform: translateZ(calc(84px * var(--k))); }
.layers:has(#explode:checked) .l-s { transform: translateZ(calc(126px * var(--k))); }
.layers:has(#explode:checked) .stage { padding-block: calc(60px * var(--k)) calc(40px * var(--k)); }
.layers:has(#show-b:not(:checked)) .l-b,
.layers:has(#show-a:not(:checked)) .l-a,
.layers:has(#show-s:not(:checked)) .l-s { opacity: 0; }
.layers .stage { transition: padding 0.9s cubic-bezier(.2,.7,.1,1); }
@media (prefers-reduced-motion: reduce) {
  .stack, .stack .layer, .stack img, .layers .stage { transition: none; }
}
.priority { list-style: none; counter-reset: p; margin: 0; padding: 0; font-family: var(--display); font-size: 0.9rem; }
.priority li { counter-increment: p; display: grid; grid-template-columns: 1.8rem 1fr; padding: 0.35rem 0; border-bottom: 1px solid var(--rule); }
.priority li::before { content: counter(p); font-family: var(--mono); color: var(--red-ink); font-size: 0.78rem; padding-top: 0.12rem; }
.tiles-fig img { width: 100%; max-width: 1024px; image-rendering: pixelated; image-rendering: crisp-edges; background: #000; }
.cram-fig img { width: 100%; max-width: 384px; image-rendering: pixelated; image-rendering: crisp-edges; }

/* ---------------------------------------------------------------- FM */
.fm .controls { display: grid; grid-template-columns: 1fr; gap: 0.9rem 2rem; margin-bottom: 1.4rem; font-family: var(--display); font-size: 0.88rem; }
@media (min-width: 700px) { .fm .controls { grid-template-columns: repeat(3, 1fr); } }
.fm label { display: grid; gap: 0.3rem; }
.fm label span { display: flex; justify-content: space-between; color: var(--ink-2); }
.fm output { font-family: var(--mono); color: var(--ink); }
.fm input[type="range"] { width: 100%; accent-color: var(--red); }
.fm svg { width: 100%; height: auto; }
.fm .trace-m { stroke: var(--ink-3); stroke-width: 1.5; fill: none; }
.fm .trace-c { stroke: var(--gold); stroke-width: 1.5; fill: none; }
.fm .trace-o { stroke: var(--red); stroke-width: 2.5; fill: none; }
.fm .lane { fill: var(--ink-3); font-family: var(--mono); font-size: 12px; letter-spacing: 0.06em; }
.fm .zero { stroke: var(--rule); stroke-width: 1; }
.wave { height: clamp(90px, 14vw, 170px); background: var(--red); -webkit-mask-size: 100% 100%; mask-size: 100% 100%; -webkit-mask-repeat: no-repeat; mask-repeat: no-repeat; }
.wave.ink { background: var(--ink-2); }
.algos { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 1px; background: var(--rule); border: 1px solid var(--rule); }
@media (min-width: 700px) { .algos { grid-template-columns: repeat(4, minmax(0, 1fr)); } }
.algos figure { margin: 0; background: var(--bg-2); padding: 0.8rem 0.6rem 0.6rem; }
.algos svg { width: 100%; height: auto; }
.algos figcaption { margin: 0.2rem 0 0; font-family: var(--mono); font-size: 0.7rem; color: var(--ink-3); }
.algos .op { fill: var(--bg); stroke: var(--ink-2); stroke-width: 1.5; }
.algos .op.car { fill: var(--red); stroke: var(--red); }
.algos text { font-family: var(--mono); font-size: 11px; fill: var(--ink); text-anchor: middle; }
.algos .op.car + text { fill: #fff; }
.algos .ln { stroke: var(--ink-3); stroke-width: 1.4; fill: none; }

/* ---------------------------------------------------------------- detective */
.bits { font-family: var(--mono); font-size: clamp(0.9rem, 0.7rem + 0.9vw, 1.5rem); line-height: 1.5; letter-spacing: 0.04em; }
.bits .row { display: grid; grid-template-columns: 6.6em auto 1fr; gap: 0 1.2em; align-items: baseline; padding: 0.4rem 0; border-bottom: 1px solid var(--rule); }
.bits .row span:last-child { font-size: 0.62em; color: var(--ink-2); letter-spacing: 0.02em; }
.bits b { color: var(--red-ink); font-weight: 700; background: var(--sel); }
@media (max-width: 600px) { .bits .row { grid-template-columns: 1fr; } }

/* ---------------------------------------------------------------- debugger */
.debugger-fig .shot { position: relative; background: var(--plate); padding: clamp(6px, 1vw, 14px); }
.debugger-fig img { width: 100%; image-rendering: pixelated; image-rendering: crisp-edges; }
@media (min-width: 1340px) { .debugger-fig img { width: 1280px; } }
.callouts { list-style: none; margin: 1.2rem 0 0; padding: 0; display: grid; grid-template-columns: 1fr; gap: 0 var(--gutter); counter-reset: c; }
@media (min-width: 700px) { .callouts { grid-template-columns: 1fr 1fr; } }
@media (min-width: 1100px) { .callouts { grid-template-columns: repeat(3, 1fr); } }
.callouts li { counter-increment: c; display: grid; grid-template-columns: 1.8rem 1fr; padding: 0.6rem 0; border-top: 1px solid var(--rule); font-family: var(--display); font-size: 0.86rem; color: var(--ink-2); line-height: 1.45; }
.callouts li::before { content: counter(c, upper-alpha); font-family: var(--mono); color: var(--gold); }
.callouts b { color: var(--ink); }
.pin { position: absolute; width: 1.6em; height: 1.6em; border-radius: 50%; background: var(--gold); color: #000; font-family: var(--mono); font-size: clamp(9px, 1vw, 12px); font-weight: 700; display: grid; place-items: center; transform: translate(-50%, -50%); box-shadow: 0 0 0 3px var(--plate); }

/* ---------------------------------------------------------------- filmstrip */
/* Pictures at exactly 1x: 320 px wide, three to a row on wide screens. */
.filmstrip, .evidence { display: grid; grid-template-columns: 336px; justify-content: space-between; gap: clamp(28px, 3vw, 44px) var(--gutter); }
@media (min-width: 760px) { .filmstrip, .evidence { grid-template-columns: repeat(2, 336px); } }
@media (min-width: 1140px) { .filmstrip, .evidence { grid-template-columns: repeat(3, 336px); } }
.filmstrip figure, .evidence figure { margin: 0; }
.filmstrip .crt, .evidence .crt { background: var(--plate); padding: 8px; line-height: 0; }
.filmstrip img, .evidence img { width: 320px; height: auto; image-rendering: pixelated; image-rendering: crisp-edges; }
@media (max-width: 380px) { .filmstrip, .evidence { grid-template-columns: 1fr; } .filmstrip img, .evidence img { width: 100%; } }
.cases { align-self: start; }
.cases table { font-size: 0.82rem; margin-top: 0.4rem; }
.cases td, .cases th { padding: 0.38rem 0.6rem 0.38rem 0; }

/* ---------------------------------------------------------------- ledger (PRs) */
.ledger td:first-child { font-family: var(--mono); color: var(--red-ink); white-space: nowrap; }
.ledger td.when { font-family: var(--mono); font-size: 0.78rem; color: var(--ink-3); white-space: nowrap; }
.ledger td.branch { font-family: var(--mono); font-size: 0.76rem; color: var(--ink-2); }
@media (max-width: 700px) { .ledger td.branch, .ledger th.branch { display: none; } }

.steps { list-style: none; margin: 0; padding: 0; counter-reset: s; }
.steps li { counter-increment: s; display: grid; grid-template-columns: 2.6rem 1fr; padding: 0.7rem 0; border-top: 1px solid var(--rule); }
.steps li::before { content: counter(s, decimal-leading-zero); font-family: var(--mono); font-size: 0.78rem; color: var(--gold); padding-top: 0.2rem; }
.steps code { white-space: normal; }

/* Upcoming: an editorial marker, not a badge. */
.upcoming-mark { font-family: var(--mono); font-size: 0.74rem; letter-spacing: 0.08em; text-transform: uppercase; color: var(--gold); }
.upcoming-mark::before { content: ""; display: inline-block; width: 1.6rem; height: 1px; background: var(--gold); vertical-align: middle; margin-right: 0.6rem; }
.next-list { list-style: none; margin: 0; padding: 0; }
.next-list li { display: grid; grid-template-columns: 1fr; gap: 0.3rem 2rem; padding: 1.4rem 0; border-top: 1px solid var(--rule-2); }
@media (min-width: 800px) { .next-list li { grid-template-columns: 16rem 1fr; } }
.next-list h3 { margin: 0; font-family: var(--display); font-weight: 800; font-stretch: 118%; font-size: 1.45rem; line-height: 1.1; }
.next-list p { margin: 0; color: var(--ink-2); }
.next-slot { border: 1px dashed var(--rule-2); padding: 1.2rem; font-family: var(--display); font-size: 0.86rem; color: var(--ink-3); }

/* ---------------------------------------------------------------- colophon */
.colophon { margin-top: clamp(6rem, 12vw, 10rem); padding-block: 0 4rem; font-family: var(--display); font-size: 0.86rem; color: var(--ink-2); }
.colophon h2 { border-top: 1px solid var(--ink); padding-top: 0.8rem; font-family: var(--mono); font-weight: 400; font-size: 0.75rem; letter-spacing: 0.08em; text-transform: uppercase; color: var(--ink-3); margin: 0 0 1rem; }
.colophon .credits td, .colophon .credits th { font-size: 0.84rem; }
.colophon .end { margin-top: 3rem; display: flex; flex-wrap: wrap; justify-content: space-between; gap: 1rem; font-family: var(--mono); font-size: 0.74rem; color: var(--ink-3); }
.colophon .sign {
  font-family: var(--display); font-weight: 900; font-stretch: 125%;
  font-size: clamp(4rem, 18vw, 16rem); line-height: 0.8; letter-spacing: -0.05em; color: var(--ink);
  margin-top: 3rem;
}
.colophon .sign span { color: var(--red); }

/* ---------------------------------------------------------------- motion */
.js .reveal { opacity: 0; transform: translateY(18px); transition: opacity 0.8s cubic-bezier(.2,.7,.1,1), transform 0.8s cubic-bezier(.2,.7,.1,1); }
.js .reveal.is-in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  .js .reveal { opacity: 1; transform: none; transition: none; }
  .progress { display: none; }
}
@media print {
  .masthead, .theme-toggle, .layers .controls { display: none; }
  .js .reveal { opacity: 1; transform: none; }
}

/* ---------------------------------------------------------------- interface */
/* The app's own pictures (gase --dump-ui): drawn at one pixel per point on
   the desktop, two on the phone, so desktop shots are scaled by whole
   numbers and phone shots shown at their size in points. */
.ui-fig .plate { line-height: 0; }
.ui-shot { width: 100%; max-width: 960px; height: auto; image-rendering: pixelated; image-rendering: crisp-edges; }
.ui-row { display: grid; grid-template-columns: 1fr; gap: clamp(20px, 2.5vw, 36px) var(--gutter); }
@media (min-width: 760px) { .ui-row { grid-template-columns: repeat(3, minmax(0, 1fr)); } }
.ui-row figure { margin: 0; }
.ui-row .plate { padding: clamp(6px, 1vw, 12px); }
/* Scaled down here, so smooth scaling: pixelated would drop whole rows of the font. */
.ui-row img { width: 100%; height: auto; image-rendering: auto; }
.ui-row figcaption { margin-top: 0.5rem; }
/* Phones: portrait and landscape side by side, at the size of a real
   phone (390 points wide), without a drawn device around them. */
.phones { display: flex; flex-wrap: wrap; gap: clamp(20px, 3vw, 44px); align-items: flex-end; }
.phones figure { margin: 0; }
.phones .plate { padding: 0; background: #000; border: 1px solid var(--rule-2); line-height: 0; }
.phones img { display: block; width: 100%; height: auto; }
.phones .portrait { width: min(260px, 70vw); }
.phones .landscape { width: min(564px, 100%); }
.browser-fig .plate { padding: 0; border: 1px solid var(--rule-2); line-height: 0; }
.browser-fig .bar { display: flex; gap: 0.8rem; align-items: center; padding: 0.55rem 0.8rem; border-bottom: 1px solid var(--rule-2); font-family: var(--mono); font-size: 0.74rem; color: var(--ink-3); line-height: 1.2; background: var(--bg-2); }
.browser-fig .bar i { display: block; flex: none; width: 7px; height: 7px; border-radius: 50%; background: var(--rule-2); }
.browser-fig img { width: 100%; height: auto; }

/* The way into the player: a plain editorial link, underlined in red. */
.play-link { font-family: var(--display); font-weight: 700; font-stretch: 112%; text-decoration: none; border-bottom: 2px solid var(--red); padding-bottom: 0.1em; }
.play-link:hover { color: var(--red-ink); }
.play-link::after { content: " →"; color: var(--red); }

/* ---------------------------------------------------------------- LZ77 */
.lz .controls { display: grid; gap: 0.4rem; font-family: var(--display); font-size: 0.86rem; color: var(--ink-2); margin-bottom: 1.2rem; border-top: 1px solid var(--rule-2); padding-top: 0.9rem; }
.lz input[type="text"] { font: inherit; font-family: var(--mono); font-size: 1rem; color: var(--ink); background: var(--bg-2); border: 1px solid var(--rule-2); padding: 0.55rem 0.7rem; width: 100%; }
.lz input[type="text"]:focus { outline: 2px solid var(--gold); outline-offset: 1px; }
.lz-out { font-family: var(--mono); font-size: clamp(0.95rem, 0.8rem + 0.6vw, 1.3rem); line-height: 2.1; word-break: break-all; }
.lz-out .lit { color: var(--ink); }
.lz-out .ref { color: var(--red-ink); border-bottom: 2px solid var(--red); padding: 0 0.15em; margin: 0 0.1em; white-space: nowrap; }
.lz-out .ref small { font-size: 0.6em; color: var(--ink-3); margin-left: 0.25em; }
.lz-stats { margin-top: 0.8rem; font-family: var(--display); font-size: 0.82rem; color: var(--ink-3); }
.lz-stats b { color: var(--ink); font-variant-numeric: tabular-nums; }

/* ---------------------------------------------------------------- memory */
.mem svg { width: 100%; height: auto; font-family: var(--mono); }
.mem .cell { fill: var(--bg-2); stroke: var(--rule-2); }
.mem .cell.hot { fill: var(--sel); stroke: var(--red); }
.mem text { fill: var(--ink-2); font-size: 13px; }
.mem .big { fill: var(--ink); font-family: var(--display); font-weight: 800; font-stretch: 112%; font-size: 17px; }
.mem .wire { stroke: var(--ink-3); stroke-width: 1.4; fill: none; }
.mem .wire.red { stroke: var(--red); }
.mem .arrow { fill: var(--ink-3); }
.hero .try { margin-top: 1.2rem; font-size: 1.05rem; }
@media (min-width: 760px) { .ui-row.two { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
.hero .try .or { color: var(--ink-3); margin: 0 0.5em; font-family: var(--display); font-size: 0.9rem; }
/* A long command in running text may break, anywhere, rather than widen the page. */
p code.wrap { white-space: normal; overflow-wrap: anywhere; }