:root{color-scheme:dark;--bg:#081b24;--panel:#102a35;--text:#e7f1f2;--muted:#aac2cb;--line:#31505c;--mint:#aff1db;--gold:#f6c58e}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--text);font:16px/1.6 system-ui,-apple-system,"Segoe UI",sans-serif}button,input,select{font:inherit}button,a,input,select{touch-action:manipulation}button,select{color:inherit;background:#142f3a;border:1px solid #486975;border-radius:8px;padding:9px 14px;min-height:44px}button,a{ -webkit-tap-highlight-color:transparent}button{cursor:pointer}button:hover{background:#204451}button:disabled{opacity:.48;cursor:default}button.primary,a.primary{background:var(--mint);color:#092932;border-color:var(--mint);font-weight:650}button.primary:hover{background:#d0fbea}a{color:var(--mint);text-underline-offset:4px}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,summary:focus-visible{outline:3px solid var(--gold);outline-offset:4px}[hidden]{display:none!important}.skip{position:absolute;top:-90px;left:16px;background:var(--mint);color:var(--bg);padding:10px;z-index:100}.skip:focus{top:10px}.topbar{padding:17px max(24px,calc((100vw - 1420px)/2));border-bottom:1px solid var(--line);display:flex;align-items:center;gap:28px}.brand{display:flex;gap:10px;align-items:center;color:var(--text);font-size:21px;text-decoration:none}.path-label{margin-left:auto;display:flex;align-items:center;gap:12px;font-size:14px}.path-label select{min-height:38px;padding:5px 8px}main{max-width:1468px;padding:32px 24px;margin:auto}.intro-heading{display:flex;justify-content:space-between;gap:36px;align-items:center}.eyebrow{font-size:12px;letter-spacing:.17em;color:var(--mint);font-weight:650;margin:0 0 12px}.intro-heading h1{font-weight:430;font-size:clamp(34px,4.6vw,64px);line-height:1.09;letter-spacing:-.045em;margin:0}.intro-heading h1 em{font-family:Georgia,serif;font-weight:400;color:var(--mint)}.opening{max-width:440px}.opening>p:first-child{font-size:clamp(18px,2.1vw,27px);line-height:1.45;margin:0 0 14px}.muted,.model-note{font-size:14px;color:var(--muted)}.definition{margin:25px 0 23px;max-width:900px;color:#c7dce2}.definition strong{color:var(--text)}.chapters{display:grid;grid-template-columns:repeat(4,1fr);border-bottom:1px solid var(--line);gap:8px;margin-bottom:25px}.chapters button{border:0;border-bottom:3px solid transparent;background:transparent;text-align:left;border-radius:0;padding:12px 8px}.chapters span{font:14px ui-monospace,Consolas,monospace;color:var(--muted);margin-right:10px}.chapters button[aria-current=step]{border-color:var(--mint);background:#17333b}.chapters button[data-visited=true]:not([aria-current=step]){color:var(--mint)}.chapter-heading{display:flex;justify-content:space-between;gap:20px;align-items:center;margin:0 0 20px}.chapter-heading h2{font-size:clamp(25px,2.6vw,35px);font-weight:460;letter-spacing:-.025em;line-height:1.2;margin:0}.chapter-heading .eyebrow{margin-bottom:7px}.chapter-heading>p{max-width:470px;margin:0;color:var(--muted)}.workbench{display:grid;grid-template-columns:minmax(0,1.75fr) minmax(320px,1fr);gap:24px;align-items:start}.visual-column{min-width:0}.scene-shell{position:relative;border:1px solid var(--line);border-radius:18px;overflow:hidden;background:radial-gradient(ellipse at 45% 35%,#234651,#102732 55%,#0b202a)}.scene-heading{display:flex;justify-content:space-between;gap:12px;padding:16px 20px;font-size:14px;border-bottom:1px solid #2c4c57}.model-badge{color:var(--muted);font-size:11px;letter-spacing:.08em}.scene-host{height:410px;position:relative;isolation:isolate}.scene-host canvas{width:100%;height:100%;display:block;touch-action:none}.scene-placeholder{height:100%;display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center;padding:50px;max-width:560px;margin:auto}.scene-placeholder strong{font:italic 38px/1.2 Georgia,serif;color:var(--mint)}.scene-placeholder p{color:var(--muted)}.scene-overlay{position:absolute;left:24px;bottom:87px;pointer-events:none;display:grid}.scene-overlay strong{font-size:36px;font-weight:450;line-height:1.3}.scene-overlay span{font-size:12px;color:var(--muted)}.scene-toolbar{display:flex;gap:8px;align-items:center;padding:12px 16px;border-top:1px solid var(--line);background:#102a35}.scene-toolbar button{font-size:14px;padding:7px 11px}.scene-toolbar button:last-child{margin-left:auto;color:var(--mint)}.status{font-size:14px;color:var(--muted);margin:10px 2px;min-height:44px}.scene-label{position:absolute;transform:translate(-50%,-50%);pointer-events:none;display:grid;place-items:center;border:1px solid #a5d1d0;background:#071b26e8;color:#cefff0;border-radius:50%;width:27px;height:27px;font:13px ui-monospace,monospace}.part-controls{display:flex;gap:6px;flex-wrap:wrap}.part-controls button{padding:6px 10px;font-size:14px;min-height:38px}.part-controls button[aria-pressed=true]{background:#31594f;border-color:var(--mint)}.part-explanation{font-size:14px;color:#c5dce2;min-height:44px;margin:10px 0}.model-note{margin:8px 0;line-height:1.55}.guide{border-left:1px solid var(--line);padding-left:24px;min-width:0}.guide-label{display:flex;align-items:center;gap:12px;margin-bottom:21px}.guide-label>span{display:grid;place-items:center;width:40px;height:40px;flex:0 0 auto;background:var(--mint);color:#0d3c40;border-radius:50%;font:italic 25px Georgia}.guide-label p{font-size:11px;letter-spacing:.08em;margin:0;color:#c8e9e4}.guide-label small{display:block;font:12px system-ui;letter-spacing:0;margin-top:2px;color:var(--muted)}.guide h3{font-size:25px;line-height:1.25;letter-spacing:-.02em;font-weight:500;margin:22px 0 13px}.guide p{margin:12px 0}.object-options{display:grid;grid-template-columns:1fr 1fr;gap:8px}.object-options button{font-size:14px}.object-options button[aria-pressed=true]{color:var(--mint);border-color:var(--mint);background:#21433e}.insight{padding:13px 16px;border-left:3px solid var(--mint);background:#14383d;color:#d5efe9;line-height:1.55}.unit-note{display:grid;gap:5px;border-top:1px solid var(--line);padding-top:16px;font-size:14px;color:var(--muted)}.unit-note strong{color:var(--text);margin-bottom:2px}.slider-label{display:flex;justify-content:space-between;gap:15px;margin-top:18px}.slider-label output{color:var(--mint);font-family:ui-monospace,monospace}input[type=range]{width:100%;accent-color:var(--mint);min-height:32px;margin:2px 0}.range-labels{display:flex;justify-content:space-between;font-size:11px;color:var(--muted)}.detector{position:relative;overflow:hidden;border:1px solid #547381;border-radius:10px;background:#01080a}.detector canvas,.method-map canvas{width:100%;height:auto;display:block}.detector span{position:absolute;left:10px;bottom:8px;font-size:10px;color:#fff;background:#0a202ce8;padding:3px 6px}.method-map{border:1px solid var(--line);border-radius:8px;overflow:hidden;margin-top:15px}.guide label{font-size:14px}.guide select{width:100%;margin-top:7px;font-size:14px}.guide details{font-size:14px;margin:12px 0 18px;border-top:1px solid var(--line);padding-top:12px}summary{cursor:pointer;color:#cce8e4}.journey-footer{display:flex;align-items:center;gap:20px;justify-content:space-between;margin-top:26px;border-top:1px solid var(--line);padding-top:20px}.journey-footer p{font-size:14px;color:var(--muted)}#save-status{margin:15px 0 0}.discovery-panel{display:grid;grid-template-columns:1fr 1.25fr;gap:54px;padding:20px 0}.discovery-message h3{font-size:clamp(28px,3.2vw,42px);line-height:1.16;font-weight:450;margin:0 0 20px}.discovery-message>p:not(.eyebrow){color:var(--muted);max-width:440px}.takeaway{display:grid;gap:4px;margin:28px 0}.takeaway strong{color:var(--mint);margin-top:13px}.takeaway span{font-size:14px;color:var(--muted)}fieldset{border:0;padding:0;margin:0 0 24px;min-width:0}legend{font-weight:600;margin-bottom:11px}.choice{display:flex;align-items:flex-start;gap:10px;cursor:pointer;padding:10px 13px;border:1px solid var(--line);border-radius:8px;margin-bottom:7px;font-size:15px}.choice:has(input:checked){border-color:var(--mint);background:#204039}.choice input{accent-color:var(--mint);margin:6px 0 0;flex:0 0 auto}.review{background:#10332f;border:1px solid #477a6b;border-radius:16px;margin-top:24px;padding:25px 30px}.review h3{font-size:30px;font-weight:500;margin:5px 0 20px}.review-feedback-item{padding:12px 0;border-top:1px solid #396259}.review-feedback-item p{margin:4px 0;font-size:15px}.review-feedback-item strong{color:var(--mint)}.review-actions{display:flex;gap:10px;flex-wrap:wrap;margin-top:20px}.next-lesson{font-size:20px;display:inline-block;margin-top:14px}.everyday{padding:60px 0 40px;border-bottom:1px solid var(--line);margin-top:20px}.everyday h2{font-size:34px;font-weight:450;letter-spacing:-.025em;margin:0 0 25px}.everyday>div{display:grid;grid-template-columns:repeat(3,1fr);gap:32px}.everyday article{border-top:1px solid #56717b;padding-top:20px}.everyday article>span{font-size:11px;letter-spacing:.1em;color:var(--gold)}.everyday h3{font-size:22px;font-weight:500;line-height:1.3;margin:14px 0 10px}.everyday article p{font-size:15px;color:var(--muted);margin:0}.research-notes{padding:25px 0;border-bottom:1px solid var(--line);font-size:14px;color:var(--muted)}.research-notes p{max-width:1000px}.research-notes li{margin-bottom:9px}footer{display:flex;justify-content:space-between;gap:20px;flex-wrap:wrap;padding:25px 0 10px;font-size:14px}body.record-open{background:#e7eeef;color:#18353f}body.record-open>:not(#printable-record){display:none!important}#printable-record{max-width:900px;margin:auto;padding:24px;font:16px/1.65 Arial,sans-serif}#printable-record .record-toolbar{display:flex;flex-wrap:wrap;gap:12px;margin-bottom:20px}#printable-record button{background:#194b58;color:#fff}#printable-record .record-toolbar p{width:100%;margin:0;font-size:14px}#printable-record .record-paper{padding:32px;background:#fff;overflow-wrap:anywhere}#printable-record h1{font:700 30px/1.2 Arial}#printable-record h2{font:700 22px/1.3 Arial}#printable-record li{margin-bottom:20px}#printable-record a{color:#155c72}
@media(min-width:1500px){.scene-host{height:475px}}@media(max-width:1100px){.scene-host{height:365px}.workbench{grid-template-columns:minmax(0,1.4fr) minmax(300px,1fr);gap:18px}.guide{padding-left:18px}.opening{max-width:340px}.guide h3{font-size:23px}.chapter-heading>p{max-width:370px}}@media(max-width:800px){main{padding:24px 18px}.topbar{padding:14px 18px;gap:20px;flex-wrap:wrap}.path-label{width:100%;margin:0;justify-content:space-between}.intro-heading{align-items:flex-start;gap:24px}.opening>p:first-child{font-size:18px}.intro-heading h1{font-size:36px}.opening .muted{font-size:12px}.chapters button{font-size:13px;padding:11px 4px}.chapters span{display:block;margin-bottom:3px}.chapter-heading{display:block}.chapter-heading>p{max-width:none;margin-top:10px}.workbench{grid-template-columns:1fr}.guide{border-left:0;padding:18px 0 0;border-top:1px solid var(--line)}.scene-host{height:380px}.guide-label{margin-bottom:16px}.object-options{grid-template-columns:repeat(4,1fr)}.object-options button{padding:9px 5px}.detector,.method-map{max-width:440px}.discovery-panel{grid-template-columns:1fr;gap:20px}.discovery-message .takeaway{display:none}.everyday>div{grid-template-columns:1fr}.everyday{padding-top:40px}.journey-footer{gap:8px}.journey-footer button{font-size:14px;padding:9px}.journey-footer p{font-size:12px}.scene-heading{padding:12px 15px}.model-badge{font-size:9px}}@media(max-width:480px){.intro-heading{display:block}.opening{margin-top:20px}.opening>p:first-child br{display:none}.opening .muted{font-size:13px}.intro-heading h1{font-size:36px}.scene-host{height:325px}.scene-placeholder{padding:30px}.scene-toolbar{gap:5px;padding:10px}.scene-toolbar button{font-size:12px;padding:6px 8px}.scene-overlay{left:18px;bottom:78px}.scene-overlay strong{font-size:30px}.review{padding:20px}.review-actions button{width:100%}.journey-footer p{max-width:62px;text-align:center}.object-options{grid-template-columns:1fr 1fr}}
@media(prefers-reduced-motion:no-preference){button{transition:background .15s,border-color .15s}}@media print{body.record-open{background:#fff!important}#printable-record{max-width:none;padding:0}#printable-record .record-toolbar{display:none!important}#printable-record .record-paper{padding:0}#printable-record h2{break-after:avoid}#printable-record li{break-inside:avoid}@page{margin:16mm}}
body:not(.intro-ready) .chapters,body:not(.intro-ready) .journey,body:not(.intro-ready) .path-label{display:none}.intro-ready #static-introduction{display:none}#static-introduction{border:1px solid var(--line);border-radius:16px;padding:24px;margin:20px 0;background:var(--panel);max-width:960px}#static-introduction h2{font-weight:500}#static-introduction li{margin:12px 0}.scene-label[data-selected=true]{background:var(--mint);color:#082a31;outline:3px solid #aff1db55;z-index:2}#review-score:focus{outline:2px solid var(--gold);outline-offset:6px}

.scene-leader{position:absolute;pointer-events:none;height:1px;background:#c5f1deaa;transform-origin:0 50%}