:root {
  --bg: #0b0f16;
  --panel: #121823;
  --line: #222b3a;
  --text: #e6edf3;
  --dim: #8b97a8;
  --accent: #f5c542;
  --blue: #7aa2ff;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 14px/1.45 Inter, system-ui, sans-serif;
}

.mono, .mat, .hover-info { font-family: "JetBrains Mono", ui-monospace, monospace; }
.dim { color: var(--dim); font-weight: 400; font-size: 12px; }

.top {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  gap: 16px;
  padding: 18px 20px 10px;
}
.top h1 { margin: 0; font-size: 20px; font-weight: 600; }
.top .sub { margin: 4px 0 0; color: var(--dim); }
.home { color: var(--dim); text-decoration: none; font-size: 13px; white-space: nowrap; }
.home:hover { color: var(--text); }

.app {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 400px;
  gap: 14px;
  padding: 0 20px 20px;
}
.left, .right { display: flex; flex-direction: column; gap: 14px; min-width: 0; }

.card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 12px 14px;
}
.card h3 { margin: 0 0 8px; font-size: 13px; font-weight: 600; letter-spacing: .02em; }

.view3d {
  position: relative;
  height: 60vh;
  min-height: 360px;
  border: 1px solid var(--line);
  border-radius: 10px;
  overflow: hidden;
}
.view3d canvas { display: block; }
.legend {
  position: absolute; top: 10px; left: 10px;
  display: flex; flex-wrap: wrap; gap: 12px;
  font-size: 12px; color: var(--dim);
  pointer-events: none;
}
.legend .sw { display: inline-block; width: 10px; height: 10px; border-radius: 2px; margin-right: 5px; vertical-align: -1px; }
.legend .sw.axes { background: linear-gradient(90deg, #ff5c5c 33%, #5cff8a 33% 66%, #5c9dff 66%); width: 18px; }
.hint {
  position: absolute; bottom: 8px; right: 10px;
  font-size: 11px; color: var(--dim); pointer-events: none;
}

#img {
  width: 100%;
  aspect-ratio: 4 / 3;
  display: block;
  border-radius: 6px;
  cursor: crosshair;
}

.hover-info {
  margin-top: 8px;
  min-height: 108px;
  font-size: 12px;
  color: var(--dim);
  white-space: pre;
  overflow-x: auto;
}
.hover-info b { color: var(--text); font-weight: 500; }
.hover-info .sw { display: inline-block; width: 9px; height: 9px; border-radius: 50%; margin-right: 4px; }

#matrices { display: grid; gap: 8px; }
.mrow { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.mrow .name { color: var(--dim); font-size: 12px; min-width: 64px; }
.mat {
  border-collapse: collapse;
  font-size: 12px;
  border-left: 1px solid var(--dim);
  border-right: 1px solid var(--dim);
  border-radius: 4px;
}
.mat td { padding: 1px 7px; text-align: right; }
.mat td.sep { border-left: 1px dashed var(--line); }
.note { color: var(--dim); font-size: 12px; margin: 10px 0 0; }

.anim-row { display: flex; flex-wrap: wrap; align-items: center; gap: 6px; margin-bottom: 12px; }
.label { color: var(--dim); font-size: 12px; margin-right: 4px; }
button {
  background: #1a2230;
  color: var(--text);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 5px 10px;
  font: inherit;
  font-size: 12.5px;
  cursor: pointer;
}
button:hover { border-color: #3a4658; }
button.active { background: var(--accent); color: #111; border-color: var(--accent); }
button.ghost { background: transparent; }

.groups {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px 22px;
}
.group h4 { margin: 0 0 6px; font-size: 12px; font-weight: 500; color: var(--dim); }
.srow { display: grid; grid-template-columns: 36px minmax(0, 1fr) 58px; align-items: center; gap: 8px; height: 26px; }
.srow .k { font-family: "JetBrains Mono", monospace; font-size: 12.5px; }
.srow output { font-family: "JetBrains Mono", monospace; font-size: 12px; text-align: right; color: var(--dim); }
input[type=range] { width: 100%; accent-color: var(--accent); }

.toggles { display: flex; flex-wrap: wrap; gap: 14px; margin-top: 12px; color: var(--dim); font-size: 12.5px; }
.toggles input { accent-color: var(--accent); vertical-align: -2px; }

@media (max-width: 1100px) {
  .app { grid-template-columns: minmax(0, 1fr); }
  .groups { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 640px) {
  .top { padding: 14px 16px 8px; flex-direction: column; align-items: flex-start; }
  .app { padding: 0 16px 16px; }
  .groups { grid-template-columns: minmax(0, 1fr); }
  .view3d { height: 48vh; }
}

/* Tabs */
.top-right { display: flex; align-items: center; gap: 16px; }
.tabs { display: flex; gap: 4px; background: var(--panel); border: 1px solid var(--line); border-radius: 8px; padding: 3px; }
.tabs button { border: 0; background: transparent; color: var(--dim); padding: 4px 14px; }
.tabs button.active { background: #232d3d; color: var(--text); }

/* Tooltips */
[data-tip] { cursor: help; }
span[data-tip], .k[data-tip], h4 [data-tip] { text-decoration: underline dotted #4b5768; text-underline-offset: 3px; }
.tip {
  position: fixed;
  z-index: 10;
  max-width: 320px;
  padding: 9px 11px;
  background: #1a2230;
  border: 1px solid #34405a;
  border-radius: 8px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, .45);
  font-size: 12.5px;
  line-height: 1.5;
  pointer-events: none;
}
.tip b { display: block; margin-bottom: 3px; color: var(--accent); font-weight: 600; }
.tip .f { display: block; margin-top: 5px; font-family: "JetBrains Mono", monospace; font-size: 12px; color: var(--text); }
.tip .live { display: block; margin-top: 5px; color: var(--dim); font-size: 12px; }
.legend { pointer-events: auto; }
.legend .sw.dot { border-radius: 50%; }

/* Info tab */
.info { max-width: 820px; padding: 4px 20px 48px; margin: 0 auto; }
.info section { margin-bottom: 28px; }
.info h2 { font-size: 16px; font-weight: 600; margin: 0 0 8px; }
.info p, .info li { color: #c3cdd9; }
.info li { margin-bottom: 4px; }
.info .eq {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 10px 14px;
  margin: 10px 0;
  display: grid;
  gap: 6px;
  overflow-x: auto;
}
.info .eq.center { text-align: center; }
.info .eq .step { display: inline-block; min-width: 180px; color: var(--dim); font-size: 12.5px; }
.info .mono { color: var(--text); }
.conv { border-collapse: collapse; font-size: 13px; width: 100%; }
.conv th, .conv td { border-bottom: 1px solid var(--line); padding: 6px 8px; text-align: left; }
.conv th { color: var(--dim); font-weight: 500; }
.badge { background: var(--accent); color: #111; border-radius: 4px; padding: 0 6px; font-size: 11px; margin-left: 6px; }
@media (max-width: 640px) {
  .top-right { width: 100%; justify-content: space-between; }
  .info { padding: 4px 16px 40px; }
  .conv { font-size: 12px; }
}

[hidden] { display: none !important; }

/* Chapter navigation */
.pages { display: flex; flex-wrap: wrap; gap: 4px; margin: 8px 0 2px; }
.pages a {
  color: var(--dim);
  text-decoration: none;
  font-size: 12.5px;
  padding: 3px 10px;
  border: 1px solid var(--line);
  border-radius: 999px;
}
.pages a:hover { color: var(--text); border-color: #3a4658; }
.pages a.active { color: #111; background: var(--accent); border-color: var(--accent); }

/* Multi-view pages: 3D + side panel, a row of images, then controls */
.app.multi .view3d { height: 52vh; }
.app.multi .images, .app.multi .controls { grid-column: 1 / -1; }
.images { display: grid; gap: 14px; grid-template-columns: repeat(var(--n, 2), minmax(0, 1fr)); }
.images canvas { width: 100%; aspect-ratio: 4 / 3; display: block; border-radius: 6px; cursor: crosshair; }
.vdot { display: inline-block; width: 9px; height: 9px; border-radius: 50%; margin-right: 6px; }
.presets { display: flex; flex-wrap: wrap; align-items: center; gap: 6px; margin-bottom: 12px; }
.app.multi .hover-info { min-height: 150px; }
.readout { font-family: "JetBrains Mono", monospace; font-size: 12px; color: var(--dim); white-space: pre; overflow-x: auto; }
.readout b { color: var(--text); font-weight: 500; }
.good { color: #5cff8a; }
.bad { color: #ff7a7a; }
@media (max-width: 760px) {
  .images { grid-template-columns: minmax(0, 1fr); }
}
.info a { color: var(--accent); }

/* Charts and comparison tables */
.chart { width: 100%; height: 150px; display: block; }
.spy { width: 100%; max-width: 240px; aspect-ratio: 1; display: block; image-rendering: pixelated; border: 1px solid var(--line); border-radius: 4px; }
.cmp { width: 100%; border-collapse: collapse; font-size: 12.5px; }
.cmp th, .cmp td { text-align: left; padding: 5px 6px; border-bottom: 1px solid var(--line); }
.cmp th { color: var(--dim); font-weight: 500; }
.cmp td:nth-child(2) { font-family: "JetBrains Mono", monospace; }
.cmp tr.cur td { background: #1a2230; }
.cmp tr.cur td:first-child { box-shadow: inset 3px 0 0 var(--accent); }

/* Splatting explainer */
.pages a.prereq { border-style: dashed; }
.cmp.px td { padding: 3px 6px; font-size: 12px; }
.cmp.px td:not(:first-child) { font-family: "JetBrains Mono", monospace; }
.cmp .sw { display: inline-block; width: 9px; height: 9px; border-radius: 50%; margin-right: 5px; }
.bar { display: inline-block; width: 60px; height: 8px; background: #1c2430; border-radius: 4px; margin-right: 6px; vertical-align: middle; overflow: hidden; }
.bar i { display: block; height: 100%; }