:root {
  --zt-ink: #10131a;
  --zt-ink-soft: #4a5364;
  --zt-paper: #f6f4ef;
  --zt-card: #ffffff;
  --zt-edge: #d9d4c8;
  --zt-brass: #a8762a;
  --zt-brass-soft: #f0e2c6;
  --zt-fwd: #1f6f50;
  --zt-rev: #a3341f;
  --zt-still: #2d4f86;
  --zt-shade: #f0ece1;
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  background: var(--zt-paper); color: var(--zt-ink);
  font: 16px/1.55 "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, serif;
  -webkit-text-size-adjust: 100%;
}
header.top { padding: 22px 20px 0; max-width: 1040px; margin: 0 auto; }
.brand h1 { margin: 0 0 6px; font-size: 30px; letter-spacing: -0.01em; }
.brand .tag { margin: 0 0 14px; color: var(--zt-ink-soft); max-width: 72ch; font-size: 15px; }
nav.tabs { display: flex; flex-wrap: wrap; gap: 6px; border-bottom: 2px solid var(--zt-edge); padding-bottom: 0; }
.tab {
  font: inherit; font-size: 14px; background: transparent; border: 1px solid transparent;
  border-bottom: none; padding: 7px 12px; cursor: pointer; color: var(--zt-ink-soft);
  border-radius: 6px 6px 0 0;
}
.tab:hover { color: var(--zt-ink); background: var(--zt-shade); }
.tab[aria-pressed="true"] { background: var(--zt-card); border-color: var(--zt-edge); color: var(--zt-ink); font-weight: 600; margin-bottom: -2px; padding-bottom: 9px; }
main { max-width: 1040px; margin: 0 auto; padding: 18px 20px 40px; }
.panel { background: var(--zt-card); border: 1px solid var(--zt-edge); border-radius: 10px; padding: 16px; margin: 0 0 18px; }
.panel.view[hidden] { display: none !important; }
.controls { display: grid; grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); gap: 12px 20px; }
.ctl label, .ctl .lbl { display: block; font-size: 13px; color: var(--zt-ink-soft); margin-bottom: 3px; }
.ctl output { color: var(--zt-ink); font-weight: 600; font-variant-numeric: tabular-nums; }
.ctl input[type=range] { width: 100%; accent-color: var(--zt-brass); }
.ctl.machinepick { display: flex; flex-wrap: wrap; align-items: center; gap: 6px; }
.ctl.machinepick .lbl { width: 100%; margin: 0; }
.mbtn, .ctl.buttons button {
  font: inherit; font-size: 14px; padding: 6px 12px; border: 1px solid var(--zt-edge);
  background: var(--zt-paper); color: var(--zt-ink); border-radius: 6px; cursor: pointer;
}
.mbtn[aria-pressed="true"] { background: var(--zt-brass-soft); border-color: var(--zt-brass); font-weight: 600; }
.mbtn:hover, .ctl.buttons button:hover { background: var(--zt-shade); }
.ctl.buttons { display: flex; align-items: flex-end; gap: 8px; flex-wrap: wrap; }
.ctl.dim { opacity: 0.35; }
.ctl.dim input { pointer-events: none; }
.stage { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 16px; }
figure.cbox { margin: 0; }
figure.cbox figcaption { font-size: 12.5px; color: var(--zt-ink-soft); margin-bottom: 6px; }
figure.cbox canvas { width: 100%; height: auto; display: block; background: #12151c; border-radius: 8px; border: 1px solid var(--zt-edge); }
figure.cbox.wide { margin-top: 16px; }
.readout { margin-top: 16px; display: grid; grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); gap: 10px; }
.rcell { background: var(--zt-shade); border-radius: 8px; padding: 9px 11px; }
.rcell .k { display: block; font-size: 11.5px; text-transform: uppercase; letter-spacing: 0.06em; color: var(--zt-ink-soft); }
.rcell .v { display: block; font-size: 19px; font-weight: 600; font-variant-numeric: tabular-nums; }
.rcell.forward .v { color: var(--zt-fwd); }
.rcell.reverse .v { color: var(--zt-rev); }
.rcell.standstill .v { color: var(--zt-still); }
.rcell.tie .v { color: var(--zt-brass); }
.prose { font-size: 15px; }
.prose h2 { font-size: 21px; margin: 22px 0 8px; }
.prose h2:first-child { margin-top: 4px; }
.prose h3 { font-size: 16.5px; margin: 18px 0 6px; }
.prose p, .prose li { max-width: 74ch; }
.prose ul { padding-left: 20px; }
.prose code { font-family: "SF Mono", Menlo, Consolas, monospace; font-size: 13.5px; background: var(--zt-shade); padding: 1px 4px; border-radius: 4px; }
.prose table { border-collapse: collapse; margin: 10px 0 16px; font-size: 13.5px; width: 100%; }
.prose th, .prose td { border: 1px solid var(--zt-edge); padding: 5px 8px; text-align: left; vertical-align: top; }
.prose th { background: var(--zt-shade); font-weight: 600; }
.prose td.num { text-align: right; font-variant-numeric: tabular-nums; }
.prose .lede { font-size: 16.5px; border-left: 3px solid var(--zt-brass); padding-left: 12px; color: var(--zt-ink); }
.prose .caveat { background: var(--zt-brass-soft); border-radius: 8px; padding: 10px 13px; font-size: 14px; }
.prose .tag-doc, .prose .tag-meas, .prose .tag-der, .prose .tag-qual, .prose .tag-recon {
  font-size: 11px; letter-spacing: 0.06em; text-transform: uppercase; padding: 1px 6px;
  border-radius: 4px; font-family: "SF Mono", Menlo, Consolas, monospace; white-space: nowrap;
}
.prose .tag-doc { background: #dfeadd; color: #2a5a36; }
.prose .tag-meas { background: #dde6f2; color: #274b76; }
.prose .tag-der { background: #efe3d2; color: #7a5312; }
.prose .tag-qual { background: #efe0e6; color: #78304b; }
.prose .tag-recon { background: #e8e5de; color: #4a4a44; }
.foot { max-width: 1040px; margin: 0 auto; padding: 0 20px 36px; font-size: 13px; color: var(--zt-ink-soft); }
.foot a { color: var(--zt-brass); }
@media (max-width: 620px) {
  .brand h1 { font-size: 24px; }
  main { padding: 14px 12px 30px; }
  header.top { padding: 16px 12px 0; }
}