:root {
  --bg: #121212;
  --panel: #1a1a1a;
  --line: #2a2a2a;
  --ink: #ececea;
  --muted: #9a9a96;
  --dim: #626260;
  --paper: #ebeae5;
  --paper-ink: #1d1d1b;
  --paper-mute: #77766f;
  --paper-rule: #b9b8b1;
  --accent: #c8102e;

  /* Overlay colours, as rgb triples so each layer can set its own alpha. */
  --ov-margin: 236, 72, 153;
  --ov-column: 14, 165, 233;
  --ov-gutter: 245, 158, 11;
  --ov-baseline: 59, 130, 246;
  --ov-module: 16, 185, 129;

  --sans: "Inter", system-ui, sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, monospace;
  color-scheme: dark;
}

* { box-sizing: border-box; }
html, body { height: 100%; margin: 0; }
body {
  display: grid;
  grid-template-columns: 384px 1fr;
  background: var(--bg);
  color: var(--ink);
  font: 14px/1.5 var(--sans);
  -webkit-font-smoothing: antialiased;
}
button { font: inherit; color: inherit; }
kbd {
  font: 500 10px var(--mono);
  padding: 1px 5px;
  border: 1px solid var(--line);
  border-radius: 3px;
  color: var(--muted);
}

/* ---------- Panel ---------- */

.panel {
  background: var(--panel);
  border-right: 1px solid var(--line);
  overflow-y: auto;
  padding: 28px 24px 40px;
}
.kicker, .block-title {
  font: 500 10.5px/1 var(--mono);
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0;
}
h1 { font: 600 26px/1.1 "Inter Tight", var(--sans); letter-spacing: -.02em; margin: 10px 0 10px; }
.lede { color: var(--muted); margin: 0; font-size: 13px; }
.block { margin-top: 30px; }
.block-title { margin-bottom: 14px; }
.hint { color: var(--dim); font-size: 12px; margin: 10px 0 0; }

.part { padding: 14px 0 16px; border-top: 1px solid var(--line); }
.part:last-child { border-bottom: 1px solid var(--line); }
.part-head { display: flex; align-items: center; gap: 10px; }
.part h3 { font-size: 14px; font-weight: 600; margin: 0; flex: 1; }
.part output { font: 500 12px var(--mono); color: var(--ink); }
.note { margin: 6px 0 12px 54px; color: var(--muted); font-size: 12.5px; line-height: 1.45; }
.control { margin-left: 54px; }
.part.off h3, .part.off .note { color: var(--dim); }

.swatch { width: 10px; height: 10px; border-radius: 2px; flex: none; }
.sw-margins  { background: rgb(var(--ov-margin)); }
.sw-columns  { background: rgb(var(--ov-column)); }
.sw-gutters  { background: rgb(var(--ov-gutter)); }
.sw-baseline { background: rgb(var(--ov-baseline)); }
.sw-modules  { background: rgb(var(--ov-module)); }

.switch { position: relative; width: 30px; height: 18px; flex: none; cursor: pointer; }
.switch input { position: absolute; inset: 0; opacity: 0; margin: 0; cursor: pointer; }
.switch .track {
  position: absolute; inset: 0; border-radius: 9px;
  background: #333; transition: background .15s;
}
.switch .knob {
  position: absolute; top: 2px; left: 2px; width: 14px; height: 14px; border-radius: 50%;
  background: #bbb; transition: transform .15s, background .15s;
}
.switch input:checked + .track { background: #4a4a48; }
.switch input:checked + .track .knob { transform: translateX(12px); background: #fff; }
.switch input:focus-visible + .track { outline: 2px solid #fff; outline-offset: 2px; }

input[type="range"] {
  width: 100%; margin: 0; height: 18px; background: none; -webkit-appearance: none; appearance: none; cursor: pointer;
}
input[type="range"]::-webkit-slider-runnable-track { height: 2px; background: #3a3a38; border-radius: 1px; }
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none; width: 14px; height: 14px; border-radius: 50%;
  background: #fff; margin-top: -6px; border: 0;
}
input[type="range"]::-moz-range-track { height: 2px; background: #3a3a38; }
input[type="range"]::-moz-range-thumb { width: 14px; height: 14px; border-radius: 50%; background: #fff; border: 0; }
input[type="range"]:focus-visible { outline: 2px solid #fff; outline-offset: 4px; border-radius: 2px; }

.seg { display: inline-flex; border: 1px solid var(--line); border-radius: 6px; overflow: hidden; }
.seg button {
  background: none; border: 0; padding: 5px 12px; cursor: pointer;
  font: 500 12px var(--mono); color: var(--muted);
}
.seg button + button { border-left: 1px solid var(--line); }
.seg button[aria-pressed="true"] { background: #e9e9e6; color: #111; }
.seg button:hover:not([aria-pressed="true"]) { color: var(--ink); background: #232323; }
.seg button:focus-visible { outline: 2px solid #fff; outline-offset: -2px; }

.play {
  display: inline-flex; align-items: center; gap: 10px;
  background: var(--ink); color: #111; border: 0; border-radius: 7px;
  padding: 10px 18px 10px 14px; font-weight: 600; cursor: pointer;
}
.play:hover { background: #fff; }
.play:focus-visible { outline: 2px solid #fff; outline-offset: 3px; }
.play-icon { width: 0; height: 0; border-left: 9px solid currentColor; border-top: 6px solid transparent; border-bottom: 6px solid transparent; }
.play.running .play-icon { width: 10px; height: 10px; border: 0; background: currentColor; border-radius: 1px; }

.pairings { display: grid; gap: 8px; }
.pairing {
  text-align: left; background: none; border: 1px solid var(--line); border-radius: 8px;
  padding: 10px 12px; cursor: pointer; display: grid; gap: 4px;
}
.pairing:hover { border-color: #444; }
.pairing[aria-pressed="true"] { border-color: var(--ink); background: #222; }
.pairing:focus-visible { outline: 2px solid #fff; outline-offset: 2px; }
.pairing .p-head { font-size: 22px; line-height: 1.1; color: var(--ink); }
.pairing .p-text { font-size: 13px; color: var(--muted); }
.pairing .p-label { font-size: 10.5px; color: var(--dim); text-transform: uppercase; letter-spacing: .06em; }

.readout { display: grid; grid-template-columns: auto 1fr; gap: 6px 16px; margin: 0; font-size: 12.5px; }
.readout dt { color: var(--muted); }
.readout dd { margin: 0; font: 500 12px var(--mono); text-align: right; }
.readout dd.bad { color: #ff6b6b; }
.readout dd.good { color: #6fd6a5; }

.file-row { display: flex; align-items: center; gap: 8px; }
.btn {
  background: var(--ink); color: #111; border: 0; border-radius: 6px; padding: 7px 14px;
  font-weight: 600; font-size: 13px; cursor: pointer;
}
.btn.ghost { background: none; color: var(--ink); border: 1px solid var(--line); }
.btn.small { padding: 5px 10px; font-size: 12px; font-weight: 500; }
.btn:disabled { opacity: .35; cursor: default; }
.btn:focus-visible { outline: 2px solid #fff; outline-offset: 2px; }
.status { font: 12px var(--mono); color: var(--muted); }

/* ---------- Stage ---------- */

.stage { display: grid; grid-template-rows: auto 1fr auto; min-width: 0; height: 100vh; }
.stage-bar { display: flex; justify-content: flex-end; gap: 10px; padding: 14px 20px 0; }
.viewport { overflow: hidden; display: flex; padding: 20px; min-height: 0; }
.viewport.scrolling { overflow: auto; }
.paper-wrap { position: relative; margin: auto; flex: none; }
.paper {
  position: absolute; left: 0; top: 0; transform-origin: 0 0;
  background: var(--paper);
  box-shadow: 0 1px 2px rgba(0,0,0,.4), 0 18px 50px rgba(0,0,0,.45);
  overflow: hidden;
}
.narration {
  margin: 0; padding: 10px 20px 18px; min-height: 48px; text-align: center;
  font: 500 12px var(--mono); color: var(--muted);
}
.narration b { color: var(--ink); font-weight: 500; }

/* ---------- Poster elements (units are points: 1px inside .paper = 1pt) ---------- */

.els { position: absolute; inset: 0; }
.el { position: absolute; }
.el .txt { position: relative; color: var(--paper-ink); font-kerning: normal; }
.probe { display: inline-block; width: 0; height: 0; vertical-align: baseline; }
.k-label .txt, .k-foot .txt, .k-mono .txt { text-transform: uppercase; letter-spacing: .08em; }
.k-label.right .txt { text-align: right; }
.k-foot .lbl { color: var(--paper-mute); }
.k-foot .val { text-transform: none; letter-spacing: 0; }
.k-headline .txt { letter-spacing: -.035em; }
.k-subhead .txt { letter-spacing: -.01em; color: var(--accent); }
.k-mono .txt { color: var(--paper-mute); }
.k-rule::before { content: ""; position: absolute; left: 0; right: 0; top: 0; border-top: .75px solid var(--paper-rule); }

.k-photo .ph { position: absolute; inset: 0; background: #dddcd6; border: .75px solid #cfcec7; }
.k-photo .ph .tag {
  position: absolute; left: 12px; bottom: 12px; width: 18px; height: 18px;
  border: .75px solid #9a998f; color: #77766f;
  display: grid; place-items: center; font: 400 8px var(--mono);
}
.k-photo .ph .bar { position: absolute; right: 12px; bottom: 15px; width: 30%; max-width: 72px; border-top: 2px solid var(--paper-ink); }
.k-photo .ph .what {
  position: absolute; left: 0; right: 0; top: 50%; transform: translateY(-50%);
  text-align: center; font: 400 7px var(--mono); letter-spacing: .1em; color: #9a998f;
}

.el.overflow { outline: 1px dashed #e11d48; outline-offset: 0; }
.el.overflow::after {
  content: "overflows its cells"; position: absolute; right: 0; bottom: -10px;
  font: 500 6px var(--mono); color: #e11d48; background: var(--paper); padding: 0 2px;
}

/* ---------- Overlay (SVG, page units) ---------- */

.overlay, .hl { position: absolute; left: 0; top: 0; pointer-events: none; overflow: visible; }
.overlay *, .hl * { vector-effect: non-scaling-stroke; }
.margins .m-fill { fill: rgba(var(--ov-margin), .07); }
.margins .m-line { fill: none; stroke: rgba(var(--ov-margin), .85); stroke-width: 1; }
.columns rect { fill: rgba(var(--ov-column), .11); }
.columns text { fill: rgba(var(--ov-column), 1); font: 500 6px var(--mono); text-anchor: middle; }
.gutters rect { fill: rgba(var(--ov-gutter), .32); }
.baseline line { stroke: rgba(var(--ov-baseline), .5); stroke-width: 1; }
.modules rect { fill: rgba(var(--ov-module), .05); stroke: rgba(var(--ov-module), .8); stroke-width: 1; }
.modules text { fill: rgba(var(--ov-module), 1); font: 500 6px var(--mono); text-anchor: end; }
.hl .hl-mod { fill: rgba(200, 16, 46, .10); stroke: rgba(200, 16, 46, .35); stroke-width: 1; }
.hl .hl-box { fill: none; stroke: var(--accent); stroke-width: 2; }

@media (max-width: 900px) {
  body { grid-template-columns: 1fr; height: auto; }
  .panel { border-right: 0; border-bottom: 1px solid var(--line); }
  .stage { height: 90vh; }
}
@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; }
}