/* Chapter 02: fixed-size diagram, ordinary document flow, no scroll effects. */
.vector-overview{margin:0;border:1px solid var(--line);border-radius:13px;overflow:hidden;background:var(--surface)}
.vector-overview .comparison-canvas{aspect-ratio:8/5}
.vector-overview img{display:block;width:100%;height:auto}
.vector-overview figcaption{padding:20px 24px;display:grid;gap:8px}
.vector-overview figcaption strong{font:600 20px/1.4 var(--display)}
.vector-overview figcaption p{font-size:14px;line-height:1.7;color:var(--muted);margin:0}
.vector-lab-shell{border:1px solid var(--line);border-radius:14px;overflow:hidden;background:var(--surface)}
.vector-workbench{display:grid;grid-template-columns:minmax(0,1.2fr) minmax(390px,1fr);align-items:start}
.vector-preview{min-width:0;background:#090f17}
.vector-stage{position:relative;max-width:800px;margin-inline:auto;aspect-ratio:8/5;background:#090f17}
.vector-stage canvas,.vector-stage>img{position:relative;inset:auto;display:block;width:100%;height:auto;aspect-ratio:8/5}
.vector-stage:has(>img:not([hidden]))>canvas{display:none}
.vector-stage canvas{touch-action:pan-y;cursor:crosshair}
.vector-stage canvas:focus-visible{outline-offset:-3px}
.vector-legend{display:flex;flex-wrap:wrap;gap:10px 19px;padding:15px 20px;border-top:1px solid var(--line);font:400 10px/1.6 var(--mono);color:var(--muted)}
.vector-legend span{display:inline-flex;align-items:center;gap:8px}
.vector-legend i{width:10px;height:10px;display:inline-block;border-radius:50%;flex:none}
.vector-a-color{background:#eff5fa}.vector-b-color{background:#4ce0e3}.vector-e-color{border:2px solid #ffad59;background:transparent}
.vector-view-note,.vector-fallback-message{padding:0 20px;color:var(--dim);font-size:11px;line-height:1.7;margin:0 0 18px}
.vector-fallback-message{color:var(--muted);padding-top:16px}
.vector-readouts{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:18px 20px;padding:22px;border-block:1px solid var(--line);margin:0;background:#0b111b}
.vector-readouts>div{min-width:0}.vector-readouts dt{color:var(--dim);font:400 10px/1.5 var(--mono);margin:0 0 6px}.vector-readouts dd{margin:0;color:var(--ink);font:400 13px/1.6 var(--mono);font-variant-numeric:tabular-nums;overflow-wrap:anywhere}
.vector-geometry-note{padding:14px 22px;margin:0;border-bottom:1px solid var(--line);min-height:69px;font-size:12px;line-height:1.7;color:var(--muted)}
.vector-controls{min-width:0;padding:20px;border-left:1px solid var(--line)}
.vector-scale-control{display:grid;grid-template-columns:1fr;gap:12px;align-items:end;padding-bottom:18px;border-bottom:1px solid var(--line)}
.vector-scale-control h3{font-size:19px;margin:0 0 10px}
.vector-scale-control h3 output{font-family:var(--mono);color:#ffad59;font-size:15px;margin-left:8px}
.vector-preset-buttons{display:flex;gap:6px;flex-wrap:wrap}.vector-preset-buttons button{border-radius:7px;padding:7px 10px;font-size:10px;min-height:35px}.vector-preset-buttons button[aria-pressed=true]{border-color:#ffad59;color:#ffad59;background:#ffad5908}
.vector-point-controls{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:20px;margin-top:18px}
.vector-point-controls fieldset{min-width:0;padding:0;border:0;margin:0}
.vector-point-controls legend{padding:0;margin-bottom:4px;color:var(--ink);font:500 15px/1.5 var(--display)}
.vector-point-controls fieldset>p{font-size:10px;line-height:1.6;color:var(--dim);margin:0 0 8px}
.vector-point-controls .vector-shift-controls{grid-column:1/-1;border-top:1px solid var(--line);padding-top:14px}
.vector-shift-controls legend{float:left;width:100%}
.vector-shift-controls>p{clear:both}
.vector-component-pair{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:20px}
.vector-input-row{display:grid;grid-template-columns:12px minmax(0,1fr) 61px;gap:6px;align-items:center;margin-top:8px}
.vector-input-row label{font:400 11px/1.5 var(--mono);color:var(--muted)}
.vector-input-row input[type=range]{min-width:0;margin:0;min-height:30px;accent-color:#4ce0e3}
.vector-input-row input[type=number]{width:100%;min-width:0;border:1px solid var(--line);background:#0b111b;color:var(--ink);border-radius:6px;padding:7px 4px;font:400 11px/1.5 var(--mono);font-variant-numeric:tabular-nums}
.vector-scale-control .vector-input-row input[type=range]{accent-color:#ffad59}
.vector-interaction-help{padding:18px 22px}
.vector-keyboard-controls{display:flex;align-items:center;flex-wrap:wrap;gap:10px}
.vector-keyboard-controls>span{font-size:12px;color:var(--muted);margin-right:3px}
.vector-keyboard-controls button{font-size:11px;min-height:36px;padding:8px 11px;border-radius:6px}
.vector-keyboard-controls button[aria-pressed=true]{border-color:var(--accent);color:var(--accent)}
.vector-control-help{font-size:12px;line-height:1.75;color:var(--muted);margin:12px 0 0}
.vector-control-help strong{color:var(--ink);font-weight:500}
#vector-shader-status{font:400 10px/1.7 var(--mono);color:var(--accent);margin:15px 0 0;min-height:34px}
#vector-error{white-space:pre-wrap;overflow-wrap:anywhere;color:#ffb6a4;background:#291717;padding:16px;border-radius:8px;font-size:12px}
.vector-lab-section .code-panel{min-width:0}
@media(max-width:900px){.vector-workbench{grid-template-columns:1fr}.vector-stage{max-width:640px}.vector-controls{border-left:0;border-top:1px solid var(--line)}.vector-scale-control{grid-template-columns:minmax(0,1fr) auto;gap:18px}.vector-input-row{grid-template-columns:16px minmax(0,1fr) 72px;gap:10px}.vector-point-controls{gap:20px 30px}.vector-component-pair{gap:30px}.vector-preview{padding-bottom:1px}}
@media(max-width:580px){.vector-readouts{grid-template-columns:repeat(2,minmax(0,1fr));gap:17px;padding:18px}.vector-scale-control{grid-template-columns:1fr;gap:12px}.vector-point-controls{grid-template-columns:1fr;gap:20px}.vector-point-controls fieldset{padding-bottom:17px;border-bottom:1px solid var(--line)}.vector-point-controls .vector-shift-controls{border-top:0;border-bottom:0;padding-top:0;padding-bottom:0}.vector-component-pair{grid-template-columns:1fr;gap:0}.vector-input-row{margin-top:10px;grid-template-columns:16px minmax(0,1fr) 78px}.vector-controls{padding:20px}.vector-legend{padding:14px 18px;gap:10px 18px}.vector-view-note,.vector-fallback-message{padding-inline:18px}.vector-geometry-note{padding-inline:18px;min-height:89px}.vector-interaction-help{padding:18px}.vector-overview figcaption{padding:17px 19px}.vector-overview figcaption strong{font-size:18px}}