/* ============================================================
   gamut — an achromatic page, on purpose.

   Nothing here is coloured except the thing being measured. That is a
   colorimetric decision before it is a stylistic one: a hue anywhere in the
   frame changes how the diagram beside it reads.

   The palette is written as raw channels rather than oklch() because the
   canvas needs the same values the CSS uses, and a custom property holding
   `oklch(...)` cannot be handed to a 2D context. One source, two consumers.
   ============================================================ */

:root {
  color-scheme: light;

  --c-bg:      244 242 237;
  --c-surface: 251 250 247;
  --c-sunk:    236 234 228;
  --c-ink:      23  23  25;
  --c-ink-2:    72  71  69;
  --c-faint:   108 106 101;
  --c-rule:    198 195 188;
  --c-grid:    221 218 211;
  --c-line:     84  82  79;
  --c-grey:    205 202 195;

  --step--2: clamp(0.70rem, 0.68rem + 0.09vw, 0.76rem);
  --step--1: clamp(0.81rem, 0.79rem + 0.12vw, 0.89rem);
  --step-0:  clamp(0.95rem, 0.92rem + 0.17vw, 1.06rem);
  --step-1:  clamp(1.10rem, 1.04rem + 0.28vw, 1.30rem);
  --step-2:  clamp(1.32rem, 1.20rem + 0.54vw, 1.72rem);
  --step-3:  clamp(1.66rem, 1.40rem + 1.10vw, 2.55rem);
  --display: clamp(2.4rem, 1.15rem + 5.2vw, 5.1rem);

  --space-3xs: .25rem; --space-2xs: .5rem;  --space-xs: .75rem;
  --space-s:   1rem;   --space-m:  1.5rem;  --space-l:  2.5rem;
  --space-xl:  4rem;   --space-2xl: 6rem;
  --space-3xl: clamp(4.5rem, 9vh, 7.5rem);

  --gutter: clamp(1.1rem, .6rem + 2vw, 2.75rem);
  --page: min(100% - var(--gutter) * 2, 1240px);

  --dur-fast: .16s; --dur-base: .42s; --dur-slow: .7s;
  --ease-out: cubic-bezier(.22, 1, .36, 1);

  --sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, "SF Mono", "Cascadia Mono", "Roboto Mono", Menlo, Consolas, monospace;
}

@media (prefers-color-scheme: dark) {
  :root {
    color-scheme: dark;
    --c-bg:       19  19  21;
    --c-surface:  27  27  29;
    --c-sunk:     14  14  16;
    --c-ink:     240 239 235;
    --c-ink-2:   181 179 174;
    --c-faint:   144 142 137;
    --c-rule:     64  63  61;
    --c-grid:     43  43  45;
    --c-line:    158 156 151;
    --c-grey:     72  71  69;
  }
}

/* the switch in the corner wins over the system in both directions */
:root[data-surround="paper"] {
  color-scheme: light;
  --c-bg: 244 242 237; --c-surface: 251 250 247; --c-sunk: 236 234 228;
  --c-ink: 23 23 25; --c-ink-2: 72 71 69; --c-faint: 108 106 101;
  --c-rule: 198 195 188; --c-grid: 221 218 211; --c-line: 84 82 79; --c-grey: 205 202 195;
}
:root[data-surround="graphite"] {
  color-scheme: dark;
  --c-bg: 19 19 21; --c-surface: 27 27 29; --c-sunk: 14 14 16;
  --c-ink: 240 239 235; --c-ink-2: 181 179 174; --c-faint: 144 142 137;
  --c-rule: 64 63 61; --c-grid: 43 43 45; --c-line: 158 156 151; --c-grey: 72 71 69;
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }
body, h1, h2, p, dl, dd, figure, fieldset { margin: 0; padding: 0; }
fieldset { border: 0; }
a { color: inherit; }
[hidden] { display: none !important; }

body {
  background: rgb(var(--c-bg));
  color: rgb(var(--c-ink));
  font-family: var(--sans);
  font-size: var(--step-0);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
  transition: background-color var(--dur-base) var(--ease-out),
              color var(--dur-base) var(--ease-out);
}
::selection { background: rgb(var(--c-ink)); color: rgb(var(--c-bg)); }

.sr-only {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip-path: inset(50%); white-space: nowrap;
}
.skip {
  position: absolute; left: var(--space-s); top: -4rem; z-index: 90;
  background: rgb(var(--c-ink)); color: rgb(var(--c-bg));
  padding: .75rem 1.1rem; font-size: var(--step--1);
  text-decoration: none; border-radius: 2px;
  transition: top var(--dur-fast) var(--ease-out);
}
.skip:focus-visible { top: var(--space-s); }
:focus-visible { outline: 2px solid rgb(var(--c-ink)); outline-offset: 3px; }

.eyebrow, .mono {
  font-family: var(--mono); font-size: var(--step--2);
  letter-spacing: .13em; text-transform: uppercase; color: rgb(var(--c-faint));
}

/* ---------- header ---------- */

.head {
  width: var(--page); margin-inline: auto;
  padding-block: var(--space-m);
  display: flex; flex-wrap: wrap; gap: var(--space-s) var(--space-m);
  align-items: center; justify-content: space-between;
  font-family: var(--mono); font-size: var(--step--1);
}
.head__back { text-decoration: none; border-bottom: 1px solid transparent; }
.head__back:hover { border-bottom-color: rgb(var(--c-ink)); }
.dim { color: rgb(var(--c-faint)); }
.head__meta {
  font-size: var(--step--2); color: rgb(var(--c-faint));
  letter-spacing: .12em; text-transform: uppercase;
  margin-inline-end: auto; padding-inline-start: var(--space-m);
}
.surround {
  font: inherit; font-size: var(--step--2); letter-spacing: .1em;
  text-transform: uppercase; color: rgb(var(--c-ink-2));
  background: transparent; border: 1px solid rgb(var(--c-rule));
  border-radius: 2px; padding: .55rem .8rem; min-height: 44px;
  cursor: pointer; display: inline-flex; gap: .5ch; align-items: center;
  transition: border-color var(--dur-fast) var(--ease-out),
              color var(--dur-fast) var(--ease-out);
}
.surround b { color: rgb(var(--c-ink)); font-weight: 500; }
.surround:hover { border-color: rgb(var(--c-ink)); color: rgb(var(--c-ink)); }

/* ---------- intro ---------- */

.intro {
  width: var(--page); margin-inline: auto;
  padding-block: clamp(3rem, 12vh, 8rem) var(--space-3xl);
  display: grid; gap: var(--space-2xl);
  align-items: start;
}
.intro__lead { display: flex; flex-direction: column; gap: var(--space-m); align-items: start; }

/* the right margin of the hero carries the index, not empty paper */
.index { display: grid; gap: var(--space-m); }
.index__label {
  font-family: var(--mono); font-size: var(--step--2);
  letter-spacing: .14em; text-transform: uppercase; color: rgb(var(--c-faint));
  padding-bottom: var(--space-2xs); border-bottom: 1px solid rgb(var(--c-rule));
}
.index__list { list-style: none; margin: 0; padding: 0; display: grid; }
.index__list a {
  display: flex; gap: var(--space-s); align-items: baseline;
  min-height: 44px; padding-block: var(--space-3xs);
  text-decoration: none; font-size: var(--step--1); color: rgb(var(--c-ink-2));
  border-bottom: 1px solid rgb(var(--c-rule));
  transition: color var(--dur-fast) var(--ease-out);
}
.index__list li:last-child a { border-bottom: 0; }
.index__list a:hover { color: rgb(var(--c-ink)); }
.index__list i {
  font-family: var(--mono); font-style: normal; font-size: var(--step--2);
  color: rgb(var(--c-faint)); flex: none; width: 1.6rem;
}
.index__spec { display: grid; gap: var(--space-3xs); }
.index__spec > div { display: flex; justify-content: space-between; gap: var(--space-s); }
.index__spec dt, .index__spec dd {
  font-family: var(--mono); font-size: var(--step--2); letter-spacing: .04em;
}
.index__spec dt { color: rgb(var(--c-faint)); text-transform: uppercase; }
.index__spec dd { color: rgb(var(--c-ink-2)); }
.title {
  font-size: var(--display); line-height: .95; font-weight: 600;
  letter-spacing: -.035em; max-width: 15ch; text-wrap: balance;
  margin-block: var(--space-2xs) var(--space-2xs);
}
.lede { max-width: 46ch; font-size: var(--step-1); color: rgb(var(--c-ink-2)); }
.lede b { color: rgb(var(--c-ink)); font-weight: 600; }
.verdict {
  border-left: 2px solid rgb(var(--c-ink));
  padding-left: var(--space-m);
  font-size: var(--step-0);
  /* the real sentence arrives with the data; hold its height so nothing below moves */
  min-height: calc(3 * 1.65em);
}
.cue {
  margin-top: var(--space-l);
  font-family: var(--mono); font-size: var(--step--2);
  letter-spacing: .18em; text-transform: uppercase; color: rgb(var(--c-faint));
  transition: opacity var(--dur-base) var(--ease-out);
}
.cue::after {
  content: ""; display: inline-block; vertical-align: middle;
  width: 3.5rem; height: 1px; margin-left: .9rem;
  background: rgb(var(--c-rule));
}
.cue.is-done { opacity: 0; }

/* ---------- the instrument ---------- */

.instrument {
  width: var(--page); margin-inline: auto;
  display: grid; align-items: start;
  border-top: 1px solid rgb(var(--c-rule));
}
.stage {
  position: sticky; top: 0; z-index: 2;
  background: rgb(var(--c-bg));
  height: 62svh; min-height: 340px;
  display: grid;
  grid-template-areas: "plot" "hud";
  grid-template-rows: minmax(0, 1fr) auto;
  gap: var(--space-2xs);
  padding-block: var(--space-s);
  border-bottom: 1px solid rgb(var(--c-rule));
}
/* text scrolling up to the pinned panel fades out instead of being sliced */
.stage::after {
  content: ""; position: absolute; left: 0; right: 0; top: 100%;
  height: 1.75rem; pointer-events: none;
  background: linear-gradient(rgb(var(--c-bg)), rgb(var(--c-bg) / 0));
}
.stage__canvas { grid-area: plot; display: block; width: 100%; height: 100%; }
.stage__wait {
  grid-area: plot; align-self: center; justify-self: center;
  font-family: var(--mono); font-size: var(--step--2);
  letter-spacing: .1em; color: rgb(var(--c-faint));
}

.hud {
  grid-area: hud; align-self: end;
  pointer-events: none;
  display: flex; flex-direction: column; align-items: start;
}
.hud__state {
  font-family: var(--mono); font-size: var(--step--2);
  letter-spacing: .08em; color: rgb(var(--c-ink-2)); line-height: 1.4;
  max-width: 34ch;
}
.hud__num {
  display: flex; align-items: baseline; gap: .7ch; flex-wrap: wrap;
  font-family: var(--mono); font-size: var(--step-3); line-height: 1.1;
  font-variant-numeric: tabular-nums; letter-spacing: -.02em;
  color: rgb(var(--c-ink));
}
.hud__unit {
  font-size: var(--step--2); letter-spacing: .1em; text-transform: uppercase;
  color: rgb(var(--c-faint));
}

.inset {
  grid-area: plot; align-self: start; justify-self: end;
  width: min(34%, 9rem); text-align: right;
}
.inset__canvas {
  display: block; width: 100%; aspect-ratio: 8 / 9;
  border: 1px solid rgb(var(--c-rule));
}
.inset figcaption {
  font-family: var(--mono); font-size: var(--step--2);
  color: rgb(var(--c-faint)); margin-top: var(--space-3xs);
}

.flow { display: grid; }
.step {
  padding-block: var(--space-2xl);
  display: flex; flex-direction: column; gap: var(--space-s);
  align-items: start;
  border-bottom: 1px solid rgb(var(--c-rule));
}
.step:last-child { border-bottom: 0; }
.step__num {
  font-family: var(--mono); font-size: var(--step--2);
  letter-spacing: .18em; color: rgb(var(--c-faint));
}
.step__title {
  font-size: var(--step-3); line-height: 1.05; font-weight: 600;
  letter-spacing: -.025em; max-width: 16ch;
}
.step__body { max-width: 44ch; color: rgb(var(--c-ink-2)); }
.step__body b { color: rgb(var(--c-ink)); font-weight: 600; }
.step__aside {
  max-width: 44ch; font-size: var(--step--1); color: rgb(var(--c-faint));
  padding-left: var(--space-s); border-left: 1px solid rgb(var(--c-rule));
}

[data-reveal] {
  opacity: 0; transform: translateY(12px);
  transition: opacity var(--dur-slow) var(--ease-out),
              transform var(--dur-slow) var(--ease-out);
}
[data-reveal].is-in { opacity: 1; transform: none; }

/* ---------- the probe ---------- */

.probe {
  width: 100%; max-width: 30rem;
  display: grid; grid-template-columns: 1fr auto; align-items: baseline;
  gap: var(--space-2xs) var(--space-s);
  margin-top: var(--space-2xs);
}
.probe__label {
  font-family: var(--mono); font-size: var(--step--2);
  letter-spacing: .13em; text-transform: uppercase; color: rgb(var(--c-faint));
}
.probe__value {
  grid-row: 1; grid-column: 2; justify-self: end;
  font-family: var(--mono); font-size: var(--step-1);
  font-variant-numeric: tabular-nums; color: rgb(var(--c-ink));
}
.probe__range {
  grid-row: 2; grid-column: 1 / -1;
  width: 100%; height: 44px; margin: 0;
  background: transparent; -webkit-appearance: none; appearance: none;
  cursor: ew-resize;
}
.probe__range::-webkit-slider-runnable-track {
  height: 2px; background: rgb(var(--c-rule));
}
.probe__range::-moz-range-track { height: 2px; background: rgb(var(--c-rule)); }
.probe__range::-webkit-slider-thumb {
  -webkit-appearance: none; appearance: none;
  width: 3px; height: 26px; margin-top: -12px;
  background: rgb(var(--c-ink)); border: 0; border-radius: 0;
}
.probe__range::-moz-range-thumb {
  width: 3px; height: 26px;
  background: rgb(var(--c-ink)); border: 0; border-radius: 0;
}
.probe__range:focus-visible { outline-offset: 1px; }

.readout {
  width: 100%; max-width: 30rem;
  display: grid; gap: 1px; background: rgb(var(--c-rule));
  border: 1px solid rgb(var(--c-rule));
}
.readout > div {
  background: rgb(var(--c-surface));
  padding: var(--space-2xs) var(--space-s);
  display: flex; flex-wrap: wrap; gap: var(--space-2xs) var(--space-s);
  align-items: baseline; justify-content: space-between;
}
.readout dt {
  font-family: var(--mono); font-size: var(--step--2);
  letter-spacing: .06em; text-transform: uppercase; color: rgb(var(--c-faint));
}
.readout dd {
  font-family: var(--mono); font-size: var(--step--1);
  font-variant-numeric: tabular-nums; color: rgb(var(--c-ink));
  white-space: pre;
}
.readout .neg {
  font-weight: 700;
  border-bottom: 2px solid rgb(var(--c-ink));
}
.bar { position: relative; }
.bar::after {
  content: ""; position: absolute; left: 0; right: 0; top: -.15em;
  border-top: 1px solid currentColor;
}

.swatchLine {
  display: flex; align-items: center; gap: var(--space-s);
  max-width: 30rem;
}
.swatch {
  width: 3.4rem; height: 3.4rem; flex: none;
  background: rgb(var(--c-sunk));
  border: 1px solid rgb(var(--c-rule));
}
.swatchLine__cap {
  font-size: var(--step--1); color: rgb(var(--c-faint)); max-width: 26ch;
}

/* ---------- the gamut choice ---------- */

.choice {
  width: 100%; max-width: 30rem;
  display: grid; gap: 1px; background: rgb(var(--c-rule));
  border: 1px solid rgb(var(--c-rule));
}
.choice__opt {
  background: rgb(var(--c-surface));
  display: flex; align-items: center; gap: var(--space-s);
  padding: var(--space-xs) var(--space-s); min-height: 48px;
  cursor: pointer;
  transition: background-color var(--dur-fast) var(--ease-out);
}
.choice__opt:hover { background: rgb(var(--c-sunk)); }
.choice__opt input {
  appearance: none; -webkit-appearance: none; margin: 0;
  width: 14px; height: 14px; flex: none;
  border: 1px solid rgb(var(--c-line)); border-radius: 50%;
  display: grid; place-content: center;
}
.choice__opt input::after {
  content: ""; width: 8px; height: 8px; border-radius: 50%;
  background: rgb(var(--c-ink)); transform: scale(0);
  transition: transform var(--dur-fast) var(--ease-out);
}
.choice__opt input:checked::after { transform: scale(1); }
.choice__opt:has(input:checked) { background: rgb(var(--c-sunk)); }
.choice__name { font-size: var(--step-0); }
.choice__opt:has(input:checked) .choice__name { font-weight: 600; }
.choice__num {
  margin-left: auto;
  font-family: var(--mono); font-size: var(--step--1);
  font-variant-numeric: tabular-nums; color: rgb(var(--c-faint));
}

/* ---------- reading sections ---------- */

.section {
  width: var(--page); margin-inline: auto;
  padding-block: var(--space-3xl);
  border-top: 1px solid rgb(var(--c-rule));
}
.section__head { margin-bottom: var(--space-l); }
.section__title {
  font-size: var(--step-3); line-height: 1.05; font-weight: 600;
  letter-spacing: -.03em; margin-block: var(--space-2xs) var(--space-s);
  max-width: 18ch; text-wrap: balance;
}
.section__sub { max-width: 54ch; color: rgb(var(--c-ink-2)); font-size: var(--step-0); }
.section__sub code, .colophon code { font-family: var(--mono); font-size: .92em; }
.body { max-width: 46ch; color: rgb(var(--c-ink-2)); }
.body b { color: rgb(var(--c-ink)); font-weight: 600; }
.cols { display: grid; gap: var(--space-l); }

.panel {
  display: grid; gap: var(--space-l);
  margin-bottom: var(--space-l);
}
.specs {
  display: grid; gap: 1px; background: rgb(var(--c-rule));
  border: 1px solid rgb(var(--c-rule));
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 13rem), 1fr));
}
.specs > div { background: rgb(var(--c-surface)); padding: var(--space-s); }
.specs dt {
  font-family: var(--mono); font-size: var(--step--2);
  letter-spacing: .08em; text-transform: uppercase; color: rgb(var(--c-faint));
}
.specs dd {
  font-family: var(--mono); font-size: var(--step-1); margin-top: var(--space-3xs);
  font-variant-numeric: tabular-nums; color: rgb(var(--c-ink));
}

.test__pair { display: flex; gap: 2px; }
.test__chip { width: 5.5rem; height: 5.5rem; flex: none; }
.test__chip--srgb { background: rgb(255 0 0); }
.test__chip--p3 { background: rgb(255 0 0); }
@supports (color: color(display-p3 1 0 0)) {
  .test__chip--p3 { background: color(display-p3 1 0 0); }
}
.test__cap {
  margin-top: var(--space-s); font-size: var(--step--1); color: rgb(var(--c-faint));
}
.test__cap b { color: rgb(var(--c-ink)); font-weight: 600; }
.test__body { margin-top: var(--space-2xs); max-width: 44ch; color: rgb(var(--c-ink-2)); }

.table-wrap { overflow-x: auto; margin-bottom: var(--space-l); }
.data { border-collapse: collapse; width: 100%; min-width: 46rem; }
.data th, .data td {
  text-align: left; padding: var(--space-xs) var(--space-m) var(--space-xs) 0;
  border-bottom: 1px solid rgb(var(--c-rule));
  font-size: var(--step--1);
}
.data thead th {
  font-family: var(--mono); font-size: var(--step--2);
  letter-spacing: .08em; text-transform: uppercase;
  color: rgb(var(--c-faint)); white-space: nowrap;
}
.data tbody th { font-weight: 600; }
.data td {
  font-family: var(--mono); font-variant-numeric: tabular-nums;
  color: rgb(var(--c-ink-2)); white-space: nowrap;
}

.creds { display: grid; }
.creds > div {
  display: grid; grid-template-columns: 8.5rem minmax(0, 1fr);
  gap: var(--space-s); padding-block: var(--space-xs);
  border-bottom: 1px solid rgb(var(--c-rule));
}
.creds dt {
  font-family: var(--mono); font-size: var(--step--2);
  letter-spacing: .08em; text-transform: uppercase; color: rgb(var(--c-faint));
}
.creds dd { font-size: var(--step--1); color: rgb(var(--c-ink-2)); }
.creds a { text-decoration: none; border-bottom: 1px solid rgb(var(--c-rule)); }
.creds a:hover { border-bottom-color: rgb(var(--c-ink)); color: rgb(var(--c-ink)); }

.colophon__grid { display: grid; gap: var(--space-l); }
.colophon__note p { max-width: 46ch; color: rgb(var(--c-ink-2)); font-size: var(--step--1); }
.colophon__note p + p { margin-top: var(--space-s); }
.colophon__note b { color: rgb(var(--c-ink)); font-weight: 600; }
.cta {
  display: inline-block; margin-top: var(--space-m);
  font-size: var(--step--1); text-decoration: none;
  border-bottom: 2px solid rgb(var(--c-ink)); padding-bottom: 2px;
}
.cta:hover { color: rgb(var(--c-ink-2)); border-bottom-color: rgb(var(--c-rule)); }

.foot {
  width: var(--page); margin-inline: auto;
  padding-block: var(--space-l) var(--space-2xl);
  border-top: 1px solid rgb(var(--c-rule));
  display: flex; flex-wrap: wrap; gap: var(--space-s) var(--space-l);
  justify-content: space-between;
  font-family: var(--mono); font-size: var(--step--2); color: rgb(var(--c-faint));
}
.foot p { max-width: 60ch; }
.foot a { text-decoration: none; border-bottom: 1px solid rgb(var(--c-rule)); }
.foot a:hover { color: rgb(var(--c-ink)); border-bottom-color: rgb(var(--c-ink)); }

/* ---------- wider than a phone ---------- */

@media (min-width: 48rem) {
  .cols { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: var(--space-2xl); }
  .colophon__grid { grid-template-columns: repeat(2, minmax(0, 1fr)); column-gap: var(--space-2xl); }
  .panel { grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr); align-items: start; }
}

@media (min-width: 64rem) {
  .intro {
    grid-template-columns: minmax(0, 1.55fr) minmax(0, 1fr);
    column-gap: var(--space-2xl);
  }
  .index { padding-top: var(--space-l); max-width: 22rem; justify-self: end; width: 100%; }
  .instrument {
    grid-template-columns: minmax(0, 1.02fr) minmax(0, .98fr);
    column-gap: var(--space-2xl);
  }
  .stage {
    height: 100svh; padding-block: var(--space-l);
    border-bottom: 0;
  }
  .stage::after { display: none; }
  .step {
    min-height: 100svh; justify-content: center;
    padding-block: var(--space-2xl);
    border-bottom: 0;
  }
  .hud { max-width: 22rem; }
}

/* ---------- calm ---------- */

@media (prefers-reduced-motion: reduce) {
  .cue { display: none; }
  [data-reveal] { opacity: 1; transform: none; }
  .step { min-height: 0; }
  .stage { position: relative; top: auto; height: min(78svh, 640px); }
  .stage::after { display: none; }
  *, *::before, *::after {
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
    scroll-behavior: auto !important;
  }
}