/* Chapter 09: fixed view, one frame per change, ordinary page scrolling. */
.basis-overview{margin:0;border:1px solid var(--line);border-radius:13px;overflow:hidden;background:var(--surface)}
.basis-overview img{display:block;width:100%;height:auto}.basis-overview figcaption{display:grid;gap:8px;padding:20px 24px;color:var(--muted);font-size:14px;line-height:1.7}.basis-overview figcaption strong{color:var(--ink);font:600 20px/1.4 var(--display)}
.basis-lab-shell{border:1px solid var(--line);border-radius:14px;overflow:hidden;background:var(--surface)}
.basis-workbench{display:grid;grid-template-columns:minmax(0,1.2fr) minmax(390px,1fr);align-items:start}
.basis-preview{min-width:0;background:#090f17}.basis-stage{position:relative;aspect-ratio:8/5;background:#090f17}
.basis-stage canvas,.basis-stage>img{display:block;width:100%;height:100%;object-fit:contain}
.basis-stage:has(>img:not([hidden]))>canvas{display:none}.basis-stage canvas{touch-action:pan-y pinch-zoom;cursor:crosshair}.basis-stage canvas:focus-visible{outline-offset:-3px}.basis-stage [hidden]{display:none!important}
.basis-legend{display:flex;flex-wrap:wrap;gap:10px 18px;padding:15px 20px;border-top:1px solid var(--line);font:400 10px/1.6 var(--mono);color:var(--muted)}
.basis-legend span{display:inline-flex;align-items:center;gap:8px}.basis-legend i{width:10px;height:10px;display:inline-block;border-radius:50%;flex:none}
.basis-x-color{border:2px solid #ff9147}.basis-legend .basis-y-color{border:2px solid #66de8f;border-radius:0}.basis-world-color{background:#3de0f0}.basis-target-color{border:2px solid #ffcf4f}
.basis-view-note,.basis-fallback-message{padding:0 20px;color:var(--dim);font-size:11px;line-height:1.7;margin:0 0 18px}.basis-fallback-message{color:var(--muted);padding-top:16px}
.basis-controls{min-width:0;padding:20px;border-left:1px solid var(--line)}
.basis-heading-row{display:flex;justify-content:space-between;gap:12px;align-items:center}.basis-heading-row h3{margin:0;font:500 18px/1.5 var(--display)}
.basis-heading-row button,.basis-preset-buttons button{border-radius:7px;padding:8px 10px;font-size:10px;min-height:36px}.basis-heading-row button{flex:none}
.basis-selected-row{display:flex;align-items:center;gap:12px;margin-top:17px}.basis-selected-row label{font:400 11px/1.5 var(--mono);color:var(--muted)}
.basis-selected-row select{flex:1;min-width:100px;max-width:100%;background:#0b111b;border:1px solid var(--line);border-radius:7px;color:var(--ink);padding:9px;font:400 11px/1.5 var(--mono)}
.basis-axis-controls{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px;margin-top:17px}
.basis-controls fieldset{min-width:0;padding:0;border:0;margin:0}.basis-controls legend{padding:0;color:var(--ink);font:500 14px/1.5 var(--display)}
.basis-input-row{display:grid;grid-template-columns:25px minmax(0,1fr) 74px;gap:5px;align-items:center;margin-top:9px}
.basis-input-row label{font:400 10px/1.5 var(--mono);color:var(--muted)}
.basis-input-row input[type=range]{min-width:0;width:100%;margin:0;min-height:30px;accent-color:#ff9147}
.basis-axis-controls fieldset:nth-child(2) input[type=range]{accent-color:#66de8f}
.basis-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}
.basis-controls .basis-local-controls{margin-top:19px}.basis-local-controls .basis-input-row{grid-template-columns:58px minmax(0,1fr) 90px;gap:8px}.basis-local-controls input[type=range]{accent-color:#3de0f0}
.basis-preset-buttons{display:flex;flex-wrap:wrap;gap:8px;margin-top:14px}
.basis-small-note{font-size:10px;line-height:1.65;color:var(--dim);margin:10px 0 0}.basis-option-row{margin-top:17px;display:flex;flex-wrap:wrap;gap:12px 20px}.basis-option-row label{font-size:11px;color:var(--muted);display:flex;gap:8px;align-items:center}.basis-option-row input{accent-color:#3de0f0}
#basis-shader-status{font:400 10px/1.7 var(--mono);color:var(--accent);margin:15px 0 0;min-height:34px}
.basis-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}
.basis-readouts>div{min-width:0}.basis-readouts dt{color:var(--dim);font:400 10px/1.6 var(--mono);margin:0 0 6px}.basis-readouts dd{margin:0;color:var(--ink);font:400 14px/1.6 var(--mono);font-variant-numeric:tabular-nums;overflow-wrap:anywhere}
.basis-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)}
.basis-readout-note,.basis-control-help{padding:0 22px;font-size:12px;line-height:1.75;color:var(--muted);margin:16px 0}.basis-readout-note{color:var(--dim);font-size:11px}
#basis-error{white-space:pre-wrap;overflow-wrap:anywhere;color:#ffb6a4;background:#291717;padding:16px;border-radius:8px;font-size:12px}.basis-lab-section .code-panel{min-width:0}
@media(max-width:900px){.basis-workbench{grid-template-columns:1fr}.basis-stage{max-width:800px;margin-inline:auto}.basis-controls{border-left:0;border-top:1px solid var(--line)}.basis-preview{padding-bottom:1px}.basis-readouts{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-width:580px){.basis-stage{aspect-ratio:1}.basis-controls{padding:18px}.basis-axis-controls{grid-template-columns:1fr;gap:16px}.basis-input-row{grid-template-columns:30px minmax(0,1fr) 90px;gap:8px}.basis-readouts{gap:17px;padding:18px}.basis-readouts dd{font-size:12px}.basis-legend{padding:14px 18px;gap:10px 18px}.basis-view-note,.basis-fallback-message,.basis-geometry-note,.basis-readout-note,.basis-control-help{padding-inline:18px}.basis-geometry-note{min-height:89px}.basis-heading-row h3{font-size:16px}}