/* Chapter 07: demand-driven preview, ordinary page scrolling. */
.projection-overview{margin:0;border:1px solid var(--line);border-radius:13px;overflow:hidden;background:var(--surface)}
.projection-overview img{display:block;width:100%;height:auto}.projection-overview figcaption{display:grid;gap:8px;padding:20px 24px;color:var(--muted);font-size:14px;line-height:1.7}.projection-overview figcaption strong{color:var(--ink);font:600 20px/1.4 var(--display)}
.projection-lab-shell{border:1px solid var(--line);border-radius:14px;overflow:hidden;background:var(--surface)}
.projection-workbench{display:grid;grid-template-columns:minmax(0,1.2fr) minmax(390px,1fr);align-items:start}
.projection-preview{min-width:0;background:#090f17}.projection-stage{position:relative;aspect-ratio:8/5;background:#090f17}
.projection-stage canvas,.projection-stage>img{display:block;width:100%;height:100%;object-fit:contain}
.projection-stage:has(>img:not([hidden]))>canvas{display:none}.projection-stage canvas{touch-action:pan-y pinch-zoom;cursor:crosshair}.projection-stage canvas:focus-visible{outline-offset:-3px}
.projection-stage [hidden]{display:none!important}.projection-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)}
.projection-legend span{display:inline-flex;align-items:center;gap:8px}.projection-legend i{width:10px;height:10px;display:inline-block;border-radius:50%;flex:none}
.projection-a-color{background:#61a3ff}.projection-b-color{background:#edd65e}.projection-probe-color{border:2px solid #ffa645}.projection-closest-color{border:2px solid #f2f2f2;background:#80ffb3}
.projection-view-note,.projection-fallback-message{padding:0 20px;color:var(--dim);font-size:11px;line-height:1.7;margin:0 0 18px}.projection-fallback-message{color:var(--muted);padding-top:16px}
.projection-controls{min-width:0;padding:20px;border-left:1px solid var(--line)}
.projection-view-control{display:flex;align-items:center;gap:10px;flex-wrap:wrap}.projection-view-control>label{font:500 15px/1.5 var(--display)}
.projection-view-control 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)}
.projection-view-control button,.projection-preset-buttons button{border-radius:7px;padding:8px 10px;font-size:10px;min-height:36px}
.projection-shape-controls{padding-block:10px 14px;border-bottom:1px solid var(--line)}
.projection-shape-controls>p{color:var(--dim);font-size:10px;line-height:1.65;margin:12px 0 0}
.projection-input-row{display:grid;grid-template-columns:76px minmax(0,1fr) 67px;gap:8px;align-items:center;margin-top:9px}
.projection-input-row label{font:400 10px/1.5 var(--mono);color:var(--muted)}
.projection-input-row input[type=range]{min-width:0;width:100%;margin:0;min-height:30px;accent-color:#4ce0e3}
.projection-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}
.projection-point-controls{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:18px;margin-top:17px}
.projection-point-controls fieldset{min-width:0;padding:0;border:0;margin:0}.projection-point-controls legend{padding:0;color:var(--ink);font:500 15px/1.5 var(--display)}
.projection-point-controls .projection-input-row{grid-template-columns:10px minmax(0,1fr) 84px;gap:5px}.projection-point-controls fieldset:last-child input[type=range]{accent-color:#ffad59}
.projection-preset-buttons{display:flex;flex-wrap:wrap;gap:8px;margin-top:18px}
#projection-shader-status{font:400 10px/1.7 var(--mono);color:var(--accent);margin:15px 0 0;min-height:34px}
.projection-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}
.projection-readouts>div{min-width:0}.projection-readouts dt{color:var(--dim);font:400 10px/1.6 var(--mono);margin:0 0 6px}.projection-readouts dd{margin:0;color:var(--ink);font:400 14px/1.6 var(--mono);font-variant-numeric:tabular-nums;overflow-wrap:anywhere}
.projection-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)}
.projection-readout-note,.projection-control-help{padding:0 22px;font-size:12px;line-height:1.75;color:var(--muted);margin:16px 0}.projection-readout-note{color:var(--dim);font-size:11px}
#projection-error{white-space:pre-wrap;overflow-wrap:anywhere;color:#ffb6a4;background:#291717;padding:16px;border-radius:8px;font-size:12px}.projection-lab-section .code-panel{min-width:0}
@media(max-width:900px){.projection-workbench{grid-template-columns:1fr}.projection-stage{max-width:800px;margin-inline:auto}.projection-controls{border-left:0;border-top:1px solid var(--line)}.projection-point-controls{gap:30px}.projection-input-row{grid-template-columns:85px minmax(0,1fr) 78px}.projection-point-controls .projection-input-row{grid-template-columns:14px minmax(0,1fr) 84px;gap:8px}.projection-preview{padding-bottom:1px}}
@media(max-width:580px){.projection-stage{aspect-ratio:1}.projection-controls{padding:18px}.projection-point-controls{grid-template-columns:1fr;gap:18px}.projection-input-row{grid-template-columns:73px minmax(0,1fr) 72px;gap:6px}.projection-point-controls .projection-input-row{grid-template-columns:14px minmax(0,1fr) 84px;gap:10px}.projection-readouts{grid-template-columns:repeat(2,minmax(0,1fr));gap:17px;padding:18px}.projection-legend{padding:14px 18px;gap:10px 18px}.projection-view-note,.projection-fallback-message,.projection-geometry-note,.projection-readout-note,.projection-control-help{padding-inline:18px}.projection-geometry-note{min-height:89px}}

.projection-option-row{display:flex;align-items:center;justify-content:space-between;gap:12px;flex-wrap:wrap;margin-top:14px}.projection-option-row label{font-size:11px;color:var(--muted);display:flex;gap:8px;align-items:center}.projection-option-row input{accent-color:#33ccd4}.projection-option-row button,.projection-selection-buttons button{border-radius:7px;padding:8px 10px;font-size:10px;min-height:36px}
.projection-small-note{font-size:10px;line-height:1.65;color:var(--dim);margin:12px 0 0}.projection-point-controls .projection-probe-controls{grid-column:1/-1}.projection-probe-controls .projection-input-row{grid-template-columns:14px minmax(0,1fr) 84px;gap:10px}
.projection-selection-buttons{display:flex;align-items:center;flex-wrap:wrap;gap:8px;margin:18px 22px 0}.projection-selection-buttons>span{font-size:11px;color:var(--muted)}.projection-selection-buttons [aria-pressed=true]{border-color:var(--accent);color:var(--accent)}
@media(max-width:900px){.projection-readouts{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-width:580px){.projection-readouts dd{font-size:12px}.projection-selection-buttons{margin-inline:18px}}