:root {
  color-scheme: dark;
  --bg: #070707;
  --panel: #0c0c0c;
  --text: #f3f3ef;
  --muted: #92928c;
  --dim: #5c5c58;
  --line: #2a2a27;
  --line-soft: #1b1b19;
  --accent: #247df0;
  font-family: Inter, "SF Pro Display", "PingFang SC", system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
}

* { box-sizing: border-box; }
html, body { width: 100%; height: 100%; overflow: hidden; }
body { min-width: 320px; margin: 0; display: grid; grid-template-rows: 52px minmax(0,1fr); background: var(--bg); }
button, input { font: inherit; }
button { cursor: pointer; }
h1, h2, h3, p { margin-top: 0; }
code { color: #c8c8c2; font: 500 11px/1.4 "SFMono-Regular", Consolas, monospace; }
:focus-visible { outline: 2px solid var(--text); outline-offset: 3px; }

.skip-link { position: fixed; top: 8px; left: 8px; z-index: 40; padding: 9px 12px; background: var(--text); color: #080808; transform: translateY(-170%); }
.skip-link:focus { transform: translateY(0); }
.site-header, main { width: min(1600px,100%); margin-inline: auto; }
.site-header { height: 52px; padding: 0 clamp(16px,2.5vw,40px); display: flex; align-items: center; justify-content: space-between; border-bottom: 1px solid var(--line); }
.brand { display: inline-flex; align-items: center; gap: 10px; color: var(--text); text-decoration: none; font-size: 14px; font-weight: 650; letter-spacing: -.02em; }
.brand-mark { color: var(--accent); font-family: "SFMono-Regular", Consolas, monospace; font-weight: 500; }
.header-meta { display: flex; align-items: center; gap: 18px; color: var(--dim); font: 500 10px/1 "SFMono-Regular", Consolas, monospace; letter-spacing: .08em; }
.principle-toggle { display: none; min-height: 34px; padding: 0 10px; border: 1px solid var(--line); border-radius: 3px; background: #101010; color: var(--muted); font-size: 11px; letter-spacing: 0; }

main { height: calc(100dvh - 52px); min-height: 0; padding: 14px clamp(16px,2.5vw,40px) 16px; overflow: hidden; }
.motion-lab { height: 100%; min-height: 0; display: grid; grid-template-rows: auto minmax(0,1fr); gap: 12px; }
.intro-row { min-height: 54px; display: grid; grid-template-columns: 1fr minmax(280px,440px); align-items: end; gap: 36px; }
.eyebrow { margin: 0 0 6px; color: var(--dim); font: 500 9px/1.2 "SFMono-Regular", Consolas, monospace; letter-spacing: .1em; }
h1 { margin-bottom: 0; font-size: clamp(34px,3.6vw,48px); font-weight: 520; line-height: .9; letter-spacing: -.06em; }
.intro-copy { max-width: 440px; margin-bottom: 0; color: #aaa9a3; font-size: 13px; line-height: 1.55; }

.workspace { min-height: 0; display: grid; grid-template-columns: minmax(0,1fr) 276px; gap: 12px; }
.viewer-column { min-height: 0; display: grid; grid-template-rows: 44px minmax(0,1fr); gap: 8px; }
.scene-tabs { display: grid; grid-template-columns: repeat(4,1fr); border: 1px solid var(--line); }
.scene-tabs button { min-width: 0; min-height: 42px; padding: 0 14px; display: flex; align-items: center; justify-content: space-between; border: 0; border-right: 1px solid var(--line); background: transparent; color: var(--muted); transition: color 180ms ease, background 180ms ease; }
.scene-tabs button:last-child { border-right: 0; }
.scene-tabs button span { color: var(--dim); font: 500 9px/1 "SFMono-Regular", Consolas, monospace; }
.scene-tabs button:hover { background: #10100f; color: var(--text); }
.scene-tabs button[aria-selected="true"] { background: var(--text); color: #090909; }
.scene-tabs button[aria-selected="true"] span { color: #5c5c58; }

.player { min-height: 0; display: grid; grid-template-rows: 58px minmax(0,1fr) 38px 54px; border: 1px solid var(--line); background: var(--panel); }
.player-header { min-height: 0; padding: 10px 18px; display: flex; justify-content: space-between; align-items: center; gap: 18px; border-bottom: 1px solid var(--line); }
.player-header p { margin: 0 0 5px; color: var(--accent); font: 500 9px/1 "SFMono-Regular", Consolas, monospace; letter-spacing: .08em; }
.player-header h2 { margin: 0; font-size: 18px; font-weight: 520; letter-spacing: -.02em; }
.scene-stats { display: flex; gap: 20px; color: var(--dim); font: 500 9px/1.2 "SFMono-Regular", Consolas, monospace; }
.scene-stats b { color: var(--muted); font-weight: 500; }

.stage { min-height: 0; position: relative; display: grid; place-items: center; overflow: hidden; isolation: isolate; background: #090909; }
.stage-grid { position: absolute; inset: 0; z-index: -1; opacity: .48; background-image: linear-gradient(var(--line-soft) 1px,transparent 1px),linear-gradient(90deg,var(--line-soft) 1px,transparent 1px); background-size: 42px 42px; mask-image: linear-gradient(to bottom,transparent,#000 12%,#000 88%,transparent); }
#motion-svg { position: absolute; left: 50%; top: 50%; width: 92%; height: 90%; max-width: 1120px; max-height: 620px; display: block; overflow: visible; transform: translate(-50%,-50%); }
.stage-status { position: absolute; inset: auto 16px 12px; display: flex; justify-content: space-between; color: var(--dim); font: 500 8px/1 "SFMono-Regular", Consolas, monospace; letter-spacing: .08em; }

.timeline { padding: 7px 16px 5px; display: grid; grid-template-columns: 38px 1fr 38px; align-items: center; gap: 12px; border-top: 1px solid var(--line); }
.timeline output { color: var(--dim); font: 500 9px/1 "SFMono-Regular", Consolas, monospace; font-variant-numeric: tabular-nums; }
.timeline output:last-child { text-align: right; }
input[type="range"] { --progress: 0%; width: 100%; height: 20px; margin: 0; appearance: none; background: transparent; cursor: pointer; }
input[type="range"]::-webkit-slider-runnable-track { height: 2px; background: linear-gradient(to right,var(--accent) 0%,var(--accent) var(--progress),#343431 var(--progress),#343431 100%); }
input[type="range"]::-webkit-slider-thumb { width: 10px; height: 10px; margin-top: -4px; appearance: none; border: 0; border-radius: 50%; background: var(--text); box-shadow: 0 0 0 4px #0c0c0c; }
input[type="range"]::-moz-range-track { height: 2px; background: #343431; }
input[type="range"]::-moz-range-progress { height: 2px; background: var(--accent); }
input[type="range"]::-moz-range-thumb { width: 10px; height: 10px; border: 0; border-radius: 50%; background: var(--text); }

.controls, .transport { display: flex; align-items: center; }
.controls { min-height: 0; padding: 7px 16px; justify-content: space-between; gap: 16px; border-top: 1px solid var(--line-soft); }
.transport { gap: 3px; }
.primary-control { min-width: 84px; height: 38px; margin-right: 4px; padding: 0 14px; display: inline-flex; align-items: center; justify-content: center; gap: 8px; border: 0; border-radius: 3px; background: var(--text); color: #080808; font-size: 12px; }
.primary-control:hover { background: #fff; }
#play-icon { width: 12px; }
.icon-control { width: 36px; height: 36px; border: 0; border-radius: 3px; background: transparent; color: var(--muted); font-size: 20px; }
.icon-control:hover { background: #191918; color: var(--text); }
.control-divider { width: 1px; height: 17px; margin: 0 6px; background: var(--line); }
.frame-readout { min-width: 68px; color: var(--muted); text-align: center; font: 500 9px/1 "SFMono-Regular", Consolas, monospace; font-variant-numeric: tabular-nums; }
.guide-toggle { min-height: 38px; padding: 0 2px; display: inline-flex; align-items: center; gap: 9px; border: 0; background: transparent; color: var(--muted); font-size: 12px; }
.guide-toggle:hover, .guide-toggle[aria-pressed="true"] { color: var(--text); }
.guide-icon { width: 14px; height: 14px; border: 1px dashed currentColor; }
#glyph-guides { display: none; pointer-events: none; }
.show-guides #glyph-guides { display: block; }
.glyph-guide { fill: none; stroke: #e2e8ed; stroke-width: .65; stroke-dasharray: 2 2; opacity: .42; vector-effect: non-scaling-stroke; }
.glyph-label { font: 600 12px/1 "SFMono-Regular", Consolas, "PingFang SC", monospace; paint-order: stroke; stroke: #090909; stroke-width: 2.5px; stroke-linejoin: round; }

.principle { min-height: 0; padding: 16px; display: grid; grid-template-rows: auto minmax(0,1fr) auto; border: 1px solid var(--line); background: var(--panel); overflow: hidden; }
.section-heading { display: flex; align-items: flex-start; justify-content: space-between; gap: 12px; }
.section-heading h2 { max-width: 210px; margin: 0; font-size: 22px; font-weight: 520; line-height: 1.05; letter-spacing: -.04em; }
.principle-close { display: none; width: 36px; height: 36px; border: 1px solid var(--line); border-radius: 3px; background: transparent; color: var(--muted); font-size: 22px; line-height: 1; }
.pipeline { min-height: 0; margin-top: 12px; display: grid; grid-template-rows: repeat(4,minmax(0,1fr)); border-top: 1px solid var(--line); }
.pipeline article { min-height: 0; padding: 10px 0; display: grid; grid-template-columns: 26px 1fr; gap: 8px; align-content: center; border-bottom: 1px solid var(--line-soft); }
.pipeline article > span { padding-top: 2px; color: var(--dim); font: 500 9px/1 "SFMono-Regular", Consolas, monospace; }
.pipeline h3 { margin: 0 0 4px; font-size: 14px; font-weight: 550; }
.pipeline p { margin: 0 0 5px; color: var(--muted); font-size: 11.5px; line-height: 1.42; }
.system-note { padding-top: 10px; display: grid; gap: 5px; color: var(--muted); }
.system-note p { margin: 0; font-size: 10.5px; line-height: 1.42; }

@media (max-width: 900px) {
  .principle-toggle { display: inline-flex; align-items: center; }
  .workspace { grid-template-columns: minmax(0,1fr); }
  .principle { position: fixed; z-index: 30; top: 52px; right: 0; bottom: 0; width: min(360px,92vw); box-shadow: -20px 0 60px rgba(0,0,0,.55); transform: translateX(102%); transition: transform 220ms ease-out; }
  .principle.is-open { transform: translateX(0); }
  .principle-close { display: inline-grid; place-items: center; }
}

@media (max-width: 620px) {
  .site-header { padding-inline: 12px; }
  .header-meta { gap: 8px; }
  .header-meta > span { display: none; }
  main { padding: 8px 10px 10px; }
  .motion-lab { gap: 7px; }
  .intro-row { min-height: 30px; display: flex; align-items: center; }
  .intro-row .eyebrow, .intro-copy { display: none; }
  h1 { font-size: 28px; line-height: 1; }
  .viewer-column { grid-template-rows: 70px minmax(0,1fr); gap: 6px; }
  .scene-tabs { grid-template-columns: repeat(2,1fr); }
  .scene-tabs button { min-height: 34px; padding-inline: 12px; }
  .scene-tabs button:nth-child(2) { border-right: 0; }
  .scene-tabs button:nth-child(-n+2) { border-bottom: 1px solid var(--line); }
  .player { grid-template-rows: 56px minmax(0,1fr) 36px 50px; }
  .player-header { padding: 8px 12px; gap: 10px; }
  .player-header h2 { font-size: 16px; }
  .scene-stats { gap: 8px; font-size: 7.5px; }
  #motion-svg { width: 98%; height: 94%; }
  .stage-status { inset-inline: 10px; bottom: 8px; font-size: 7px; }
  .timeline { padding-inline: 10px; grid-template-columns: 34px 1fr 34px; gap: 8px; }
  .controls { padding: 6px 10px; gap: 8px; }
  .primary-control { min-width: 68px; height: 36px; padding-inline: 9px; }
  .icon-control { width: 30px; height: 36px; }
  .control-divider { margin-inline: 2px; }
  .frame-readout { min-width: 58px; font-size: 8px; }
  .guide-toggle { min-width: 38px; justify-content: center; }
  .guide-toggle span:last-child { display: none; }
}

@media (max-height: 660px) and (min-width: 621px) {
  main { padding-top: 8px; padding-bottom: 8px; }
  .motion-lab { gap: 8px; }
  .intro-row { min-height: 42px; }
  .eyebrow { display: none; }
  h1 { font-size: 34px; }
  .viewer-column { grid-template-rows: 38px minmax(0,1fr); gap: 6px; }
  .scene-tabs button { min-height: 36px; }
  .player { grid-template-rows: 50px minmax(0,1fr) 34px 48px; }
  .principle { padding: 12px; }
  .pipeline article { padding-block: 6px; }
  .pipeline p { font-size: 10.5px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { transition-duration: .01ms !important; }
}