/* Layout and material treatment derived from the supplied visual reference.
   Existing semantic colors, teaching content and interaction hooks are retained. */
html[data-theme="light"]{--bg:#edf3ee;--panel:#fbfcf9;--panel2:#edf3ed;--text:#173f3e;--muted:#4f6262;--soft:#687a77;--line:#d7e2da;--line2:#e0e8e1;--mint:#1f6d5c;--surface-soft:#eaf1e9;--surface-raised:#fbfcf9;--accent-soft:#e1ece1}
body{background:radial-gradient(ellipse at 15% 40%,var(--surface-soft),transparent 65%),var(--bg)}
.topbar{height:68px;padding:0 38px;border-bottom:0;background:var(--panel);gap:20px}
.brand{font-size:19px;letter-spacing:.22em;gap:14px;white-space:nowrap}
.brand>span:last-child{display:flex;align-items:center;gap:20px}
.brand small{font-size:11px;letter-spacing:0;font-weight:400;max-width:200px;padding-left:20px;border-left:1px solid var(--line);margin:0}
.brand-symbol{font-size:40px}
.topbar nav{gap:10px}
.topbar .nav{position:relative;padding:10px 20px;border:0;border-radius:15px;font-size:12px;color:var(--text);white-space:nowrap}
.topbar .nav.active{background:var(--accent-soft);font-weight:600}
.topbar .nav.active:after{content:'';position:absolute;width:44px;height:2px;bottom:-10px;left:calc(50% - 22px);background:var(--mint);border-radius:3px}
.journey{padding:17px 48px;min-height:64px;border:0;gap:9px}
.journey button{padding-right:12px;font-size:11px;gap:12px}
.journey .step-num{height:30px;width:30px;font-size:12px;background:color-mix(in srgb,var(--panel) 50%,transparent);border-color:var(--line)}
.journey button.active .step-num{background:var(--accent-soft);border-color:color-mix(in srgb,var(--mint) 60%,var(--line));color:var(--mint)}
.journey button.active{color:var(--text);font-weight:600}
.exploration-frame{margin:0 24px 24px;border:1px solid color-mix(in srgb,var(--panel) 55%,var(--line));border-radius:24px;background:var(--panel);box-shadow:0 20px 65px #294e3c0b;overflow:clip}
.exploration-frame[hidden]{display:none}
.model-toolbar{min-height:64px;padding:10px 24px;background:color-mix(in srgb,var(--panel) 92%,var(--surface-soft));border-color:var(--line);border-radius:24px 24px 0 0;z-index:8}
.model-toolbar .activity-heading p{font-size:12px;color:var(--text)}
.model-toolbar .activity-indicator{width:10px;height:10px;box-shadow:0 0 0 7px var(--accent-soft)}
.model-toolbar .motion-toggle{border-radius:24px;padding:10px 18px;background:var(--surface-soft);border-color:var(--line);font-size:11px}
#viewOptions>summary{border-radius:22px;padding:10px 16px;background:var(--panel);font-size:11px}
.view-options-body{box-shadow:0 20px 45px #153f3022;right:18px;border-radius:16px}
.explorer{grid-template-columns:minmax(0,1fr) 370px;border:0;background:var(--panel)}
.stage,.stage.molecular-scene{height:clamp(480px,calc(100svh - 210px),860px);background:var(--surface-soft);border-radius:22px 22px 0 0}
.caption-stage-wrap{min-width:0;background:var(--panel)}
.scene-heading{top:45px;left:36px;max-width:330px}
.scene-heading .eyebrow{font-size:9px;letter-spacing:.2em;margin-bottom:18px}
.scene-heading h1{font-size:clamp(38px,4.6vw,68px);line-height:1.05;font-weight:500;max-width:370px;letter-spacing:-.05em;margin-bottom:15px}
.scene-heading>p:last-child{font-size:13px;line-height:1.7;max-width:285px}
.scene-heading.structure-heading h1{font-size:clamp(34px,3.4vw,50px)}
.scene-badge{right:30px;top:34px;font-size:7px;letter-spacing:.18em}
.stage-summary{position:absolute;left:34px;top:235px;width:245px;pointer-events:none}
.stage-summary:before{content:'';display:block;width:32px;border-top:1px solid var(--line);margin-bottom:25px}
.stage-summary>div{display:flex;gap:14px;align-items:center;margin-bottom:27px}
.stage-summary>div>span{width:38px;height:38px;display:grid;place-items:center;border:1px solid var(--line);border-radius:50%;background:color-mix(in srgb,var(--panel) 65%,transparent);flex-shrink:0}
.stage-summary svg{width:22px;height:24px;stroke:var(--mint);fill:none;stroke-width:1.25;stroke-linejoin:round;stroke-linecap:round}
.stage-summary p{display:flex;flex-direction:column;gap:3px;font-size:12px;color:var(--text)}
.stage-summary small{font-size:11px;color:var(--muted)}
.hotspot{border-radius:12px;padding:9px 12px;box-shadow:0 4px 12px #284a3820;backdrop-filter:blur(8px);font-size:12px;background:color-mix(in srgb,var(--panel) 94%,transparent);border-color:color-mix(in srgb,var(--mint) 28%,var(--line))}
.hotspot small{font-size:11px}
.explorer .inspector,.explorer:has(.molecular-scene) .inspector{height:auto;max-height:calc(100svh - 145px);overflow:auto;padding:34px 26px;background:color-mix(in srgb,var(--panel) 96%,var(--surface-soft));border-left:1px solid var(--line);border-radius:22px 22px 0 0;scrollbar-width:thin;scrollbar-color:var(--line) transparent}
.inspector .eyebrow{font-size:9px;letter-spacing:.18em;margin-bottom:17px}
.inspector h2{font-size:32px;line-height:1.16;letter-spacing:-.04em;margin-bottom:20px;color:var(--text)}
.inspector h2 em{font-weight:400}
.inspector .lead{font-size:13px;line-height:1.8}
.inspector .fact{margin-top:20px;padding:18px 16px;border:1px solid var(--line);border-radius:13px;background:color-mix(in srgb,var(--panel) 78%,var(--surface-soft));box-shadow:0 4px 8px #244d3606}
.inspector .fact strong{font-size:33px;line-height:1.2;letter-spacing:-.04em}
.inspector .fact-label{font-size:8px;line-height:1.6;letter-spacing:.13em;margin-bottom:10px}
.inspector .fact p:not(.fact-label){font-size:12px;line-height:1.7;margin-top:10px}
.inspector .annotation{font-size:11px;line-height:1.65;border:1px solid var(--line);background:var(--surface-soft);border-radius:10px;padding:13px 14px;margin:14px 0 20px}
.inspector .fact~.fact{border:0;border-top:1px solid var(--line);box-shadow:none;border-radius:0;padding:20px 0;background:none}
.context-route{display:flex;flex-wrap:wrap;gap:8px}
.context-route button{padding:8px 12px;border:1px solid var(--line);border-radius:7px;background:var(--panel);box-shadow:0 2px 5px #254d3610;font-size:10px}
.scene-dock{position:absolute;z-index:4;left:22px;right:22px;bottom:17px;display:flex;align-items:center;gap:16px;min-height:78px;padding:12px 18px;border:1px solid color-mix(in srgb,var(--panel) 55%,var(--line));border-radius:20px;background:color-mix(in srgb,var(--panel) 92%,transparent);box-shadow:0 8px 28px #34593f12;backdrop-filter:blur(12px)}
.scene-dock .scene-footer{position:static;display:flex;align-items:center;gap:22px;min-width:110px;flex:1}
.scene-dock .scene-footer>div{min-width:100px;max-width:170px}
.scene-dock .scene-footer strong{font-size:10px;line-height:1.4;overflow-wrap:anywhere}
.scene-dock .scene-footer small{font-size:8px;line-height:1.5;margin-top:3px}
.scene-dock .scale-mark{width:70px;height:7px;margin-bottom:7px}
.scene-dock .scene-footer p{font-size:10px;line-height:1.8;max-width:200px;padding-left:20px;border-left:1px solid var(--line)}
.scene-dock .camera-controls{position:static;display:flex;background:none;backdrop-filter:none;border:0;border-radius:0;padding:0;gap:4px;flex-shrink:0}
.scene-dock .camera-controls button{border:1px solid var(--line);border-radius:8px;height:36px;min-width:32px;padding:0 8px;font-size:14px;background:var(--panel)}
.scene-dock .camera-controls button[aria-pressed=true]{background:var(--accent-soft)}
.scene-dock .camera-controls #rotation{font-size:17px}
.scene-dock .camera-controls #rotation span{font-size:10px}
.scene-dock .camera-more>summary{padding:9px 6px;font-size:10px}
.scene-dock .camera-more>div{border-radius:10px;box-shadow:0 5px 20px #153f3020}
.scene-dock .scene-navigation{position:static;display:flex;gap:10px;flex-shrink:0}
.scene-dock .scene-navigation .primary{background:linear-gradient(160deg,var(--mint),color-mix(in srgb,var(--mint) 85%,#163a2e));color:#fff;box-shadow:0 5px 10px #1f6d5c28;border:1px solid color-mix(in srgb,var(--mint) 82%,#fff);border-radius:9px;padding:11px 14px;font-size:11px}
.scene-dock .scene-navigation .quiet{font-size:10px;max-width:100px;text-align:left;line-height:1.5}
.scene-dock .scene-navigation .quiet:disabled{display:none}
.stage.molecular-scene .scene-footer p{display:none}
.stage.molecular-scene .fold-overlay{bottom:116px}
#scaleGuide,.cell-color-key{margin:0 24px;border-radius:16px}
#cellCaptionControls{padding-left:24px;padding-right:24px}
.tracking-panel{bottom:122px;border-radius:15px}
html[data-theme="dark"] .exploration-frame{box-shadow:0 20px 65px #0003}
html[data-theme="dark"] .scene-dock,html[data-theme="dark"] .hotspot{box-shadow:0 8px 28px #0003}
@media(max-width:1300px){.brand small{display:none}.topbar{padding:0 26px}.topbar .nav{padding:10px 13px}.explorer{grid-template-columns:minmax(0,1fr) 330px}.scene-dock{gap:10px;padding:12px}.scene-dock .scene-footer p{display:none}.stage-summary{width:210px;top:220px}.stage-summary p{font-size:11px}.stage-summary small{font-size:10px}.inspector h2{font-size:29px}}
@media(max-width:1100px){.explorer{grid-template-columns:minmax(0,1fr) 290px}.exploration-frame{margin:0 16px 18px;border-radius:20px}.stage-summary{display:none}.scene-dock{left:14px;right:14px;gap:9px}.scene-dock .scene-navigation .quiet{max-width:80px}.scene-heading{left:26px;top:35px}.scene-heading h1{font-size:43px}.scene-heading>p:last-child{font-size:12px;max-width:230px}.explorer .inspector,.explorer:has(.molecular-scene) .inspector{padding:28px 20px}.scene-dock .scene-footer>div{max-width:120px}.scene-dock .scene-navigation .primary{max-width:190px}.journey{padding:16px 28px}}
@media(max-width:760px){
 .topbar{height:auto;min-height:64px;padding:12px 16px;gap:10px;flex-wrap:wrap}.brand{font-size:16px;gap:8px}.brand-symbol{font-size:34px}.topbar nav{order:3;width:100%;justify-content:space-between;gap:3px}.topbar .nav{font-size:10px;padding:8px 10px}.topbar .nav.active:after{display:none}.appearance-controls{margin-left:auto}.topbar>.quiet{display:none}
 .journey{padding:12px 18px;min-height:56px;gap:4px}.journey button{font-size:10px;gap:8px;padding-right:6px}.journey .step-num{width:26px;height:26px;font-size:10px}.journey button:after{margin-left:0}
 .exploration-frame{margin:0 10px 14px;border-radius:20px}.model-toolbar{padding:10px 12px;min-height:58px;border-radius:20px 20px 0 0}.model-toolbar .activity-heading p{font-size:9px;max-width:95px}.model-toolbar .motion-toggle{font-size:9px;padding:8px 10px}.model-toolbar .activity-indicator{display:none}#viewOptions>summary{font-size:9px;padding:8px 10px}
 .explorer{display:block}.stage,.stage.molecular-scene{height:clamp(490px,calc(100svh - 180px),700px);border-radius:18px 18px 0 0}.scene-heading{left:22px;top:28px;max-width:250px}.scene-heading h1{font-size:40px;margin-bottom:10px;max-width:280px}.scene-heading.structure-heading h1{font-size:34px}.scene-heading .eyebrow{font-size:8px;margin-bottom:12px}.scene-heading>p:last-child{font-size:11px;line-height:1.7;max-width:260px}.scene-badge{top:17px;right:18px;font-size:6px;letter-spacing:.12em;max-width:175px;justify-content:flex-end}
 .scene-dock{left:12px;right:12px;bottom:12px;border-radius:15px;display:grid;grid-template-columns:minmax(0,1fr) auto;gap:10px;padding:11px 12px;min-height:112px}.scene-dock .scene-footer{min-width:0}.scene-dock .scene-footer>div{max-width:180px;min-width:0}.scene-dock .scale-mark{width:55px;height:5px;margin-bottom:5px}.scene-dock .scene-footer strong{font-size:9px}.scene-dock .scene-footer small{font-size:7px}.scene-dock .camera-controls{gap:3px}.scene-dock .camera-controls button{min-width:29px;height:40px;padding:0 6px;font-size:13px}.scene-dock .camera-more>summary{font-size:9px;padding:7px 3px}.scene-dock .scene-navigation{grid-column:1/-1;width:100%;justify-content:space-between}.scene-dock .scene-navigation .quiet{display:block;max-width:100px;font-size:9px}.scene-dock .scene-navigation .primary{font-size:10px;padding:9px 12px;max-width:235px;margin-left:auto}
 .explorer .inspector,.explorer:has(.molecular-scene) .inspector{max-height:none;border-left:0;border-top:1px solid var(--line);border-radius:0;padding:26px 22px}.inspector h2{font-size:29px}.inspector .lead{font-size:12px}.hotspot{font-size:9px;padding:7px 8px;border-radius:8px;max-width:145px}.hotspot small{font-size:8px}.stage.molecular-scene .fold-overlay{bottom:146px}.tracking-panel{bottom:145px;left:16px;max-width:calc(100% - 32px)}
 #scaleGuide,.cell-color-key{margin:0 10px}.cell-color-key{padding:15px 18px}
}
@media(prefers-reduced-motion:reduce){.exploration-frame *, .scene-dock *{scroll-behavior:auto;transition:none}}

@media(min-width:761px) and (max-width:980px){.explorer{display:block}.explorer .inspector,.explorer:has(.molecular-scene) .inspector{max-height:none;border-left:0;border-top:1px solid var(--line);border-radius:0}}

html[data-theme="dark"] .scene-dock .scene-navigation .primary{color:#102b29}
.appearance-controls button{border-radius:10px;box-shadow:0 2px 5px #254d3608}
.teaching-journey{margin:18px 24px 26px;border-radius:22px}
@media(max-width:760px){.teaching-journey{margin:12px 10px 18px;border-radius:18px}}

/* One explicit tools disclosure; no action rows leak from a closed panel. */
#viewOptions:not([open])>.view-options-body{display:none!important}
#toolsToggle{display:flex;align-items:center;gap:8px;font-weight:600;min-width:82px;justify-content:center;min-height:40px}
#toolsToggle:before{content:'⚙';font-size:14px;font-weight:400}
#toolsToggle:focus-visible{outline:2px solid var(--mint);outline-offset:4px}
#toolsPanel{width:min(520px,calc(100vw - 36px));padding:18px;overscroll-behavior:contain}
.tools-section{border-bottom:1px solid var(--line);padding:0 0 16px;margin:0 0 16px}
.tools-section:last-child{border:0;padding-bottom:0;margin-bottom:0}
.tools-section[hidden]{display:none}
.tools-section h3{font:600 11px var(--sans);letter-spacing:.06em;color:var(--muted);margin:0 0 11px}
.tools-actions{display:flex;flex-wrap:wrap;gap:8px}
.tools-actions button,#toolAnimation>.motion-toggle{font-size:12px;line-height:1.4;padding:10px 12px;min-height:42px;border:1px solid var(--line);border-radius:8px;background:var(--panel);color:var(--text);text-align:left}
.tools-actions button:hover{background:var(--surface-soft);color:var(--mint)}
.tools-actions button[aria-pressed=true]{border-color:var(--mint);background:var(--accent-soft);color:var(--mint)}
#toolNavigation .spatial-controls{padding-bottom:0}
#toolAnimation .motion-speed{margin:14px 0}
#toolAnimation>.motion-explainer{display:block;margin-top:12px}
#toolAnimation>.motion-explainer>summary{font-size:12px;width:auto;display:inline-block;padding:4px 9px}
.model-toolbar .activity-actions:empty{display:none}
.stage[data-level="2"] #hotspots,.stage[data-level="3"] #hotspots{display:none}
@media(max-width:760px){#toolsToggle{font-size:11px;min-width:76px;min-height:42px}#toolsPanel{right:10px;width:min(360px,calc(100vw - 40px));padding:16px;max-height:70svh}.tools-actions button{min-height:44px;font-size:12px}.model-toolbar .activity-heading p{max-width:190px;font-size:10px}.scene-dock .camera-controls{gap:5px}}

.camera-movement:not([open])>div,.motion-explainer:not([open])>div{display:none!important}