.toggle-row{display:flex;align-items:center;justify-content:space-between;gap:15px;font-size:14px;color:#667892;margin:0 0 24px}.toggle-row small{display:block;font-size:12px;line-height:1.6;color:#8c99aa;margin-top:6px}.toggle-row input{accent-color:var(--blue);width:18px;height:18px;flex-shrink:0}.tour-button{display:block;border:1px solid #d7e2ff;border-radius:6px;background:#f4f7ff;color:#375ac2;margin-top:12px;font-size:14px;padding:7px 13px}.cut-slider[hidden]{display:none}.control-panel .part-info{grid-column:1/-1;font-size:13px}.number-wrap input{width:55px}.number-wrap span{white-space:nowrap;font-size:12px}.playback-label{max-width:145px}.scene-badge{font-size:12px}.lesson strong{line-height:1.65}.lesson-symbol{margin-top:3px}.viewer-toolbar{top:16px}.viewer-hint>span{line-height:1.5}.control-panel .eyebrow{letter-spacing:.8px}.chart-container svg{direction:ltr;display:block}.chart-container{font-size:12px}[dir=rtl] .readout strong{direction:ltr;text-align:right}[dir=rtl] .view-modes button{font-size:12px}.model-note{line-height:1.9}.control-panel{max-height:720px;overflow-y:auto;scrollbar-width:thin;scrollbar-color:#dbe2ef transparent}.part-name{flex:1}.part-button>span:last-child{margin-inline-start:0}.readout strong{font-size:22px}.model-panel #viewport{height:520px}.learn-panel{align-items:start}.part-button{line-height:1.5}.readouts small{font-size:12px}.control-panel .field-error,.library-bottom .text-button{font-size:12px}.library-bottom{padding-top:40px}.top-caption,.speed-label,.playback-label span{font-size:12px}.model-note{color:#76859a}.eyebrow{color:#6c7b92}.lesson em{color:#718099}.learn-panel #explanation{font-size:16px}.learn-panel .challenge{font-size:14px}.lesson-header p{font-size:16px}.axis-key{display:none}@media(max-width:1050px){.control-panel{max-height:740px}.model-panel #viewport{height:500px}.viewer-hint>span{max-width:145px}.view-modes button{padding-inline:9px}}@media(max-width:760px){.model-panel #viewport{height:425px}.control-panel{max-height:none}.viewer-hint>span{max-width:180px}.learn-panel #explanation{font-size:16px}.playback-label{max-width:145px}.lesson-header p{font-size:14px}.control-panel #parameters{display:block}.parameter{margin-bottom:26px}}@media(max-width:390px){.viewer-hint>span{max-width:135px}.model-panel #viewport{height:370px}}

@media(min-width:761px){.model-panel #viewport{height:445px}.control-panel{max-height:620px}}
.lesson:disabled{opacity:.6;cursor:default}

.narration-strip{padding:15px 22px;background:#fbfcfe;border-top:1px solid #e8edf4;display:flex;align-items:center;gap:12px;flex-wrap:wrap}.narration-strip>div{display:flex;flex-direction:column;gap:3px;flex:1;min-width:150px}.narration-strip #audioSubject{font-size:11px;color:#7c879b}.narration-strip audio{width:220px;height:34px}.narration-strip #audioStatus{font-size:11px;color:#617187;width:100%}.narration-strip #audioStatus:empty{display:none}.flow-guide{padding:20px 22px;border-top:1px solid #e6ecf5;background:#fbfcff}.flow-heading,.flow-actions{display:flex;align-items:center;justify-content:space-between;gap:10px}.flow-heading strong{font-size:15px}.flow-heading>span,.flow-legend,.flow-actions small{font-size:11px;color:#7b899e}.flow-legend{display:flex;gap:18px;margin:12px 0}.poor{color:#226cca}.rich{color:#c53651}.flow-steps{display:flex;gap:7px;margin:14px 0}.flow-steps button{flex:1;border:1px solid #dbe4f2;border-radius:7px;background:white;height:31px;color:#536985;font-weight:600}.flow-steps button[aria-current=true]{background:#3156d9;border-color:#3156d9;color:white}.flow-detail{display:flex;gap:12px;padding:14px;background:white;border:1px solid #e2e9f3;border-radius:9px;min-height:100px}.flow-number{font-size:25px;font-weight:700}.flow-detail strong{font-size:14px}.flow-detail p{font-size:12px;line-height:1.7;margin:5px 0 0;color:#526279}.flow-actions{margin-top:12px}.flow-actions button{background:white;border:1px solid #dbe3f0;padding:7px 12px;border-radius:6px;font-size:12px;color:#3156d9}.flow-actions small{max-width:240px;text-align:center}.model-panel{align-self:start}.control-panel{max-height:740px}#flowGuide[hidden]{display:none}@media(max-width:650px){.narration-strip{padding:14px}.narration-strip audio{width:100%;order:3}.flow-guide{padding:16px}.flow-actions small{max-width:160px}.flow-legend{gap:10px}}

.flow-caption{position:absolute;bottom:15px;left:18px;right:18px;z-index:4;border:1px solid #dce4f2;background:#fffffff0;backdrop-filter:blur(10px);border-radius:9px;display:flex;align-items:center;gap:12px;padding:12px;font-size:12px;box-shadow:0 4px 22px #243b6b0b}.flow-caption[hidden]{display:none}.flow-caption>span{font-weight:700;white-space:nowrap}.flow-caption strong{flex:1}.flow-caption button{border:0;background:#eef2ff;color:#3156d9;padding:6px 10px;border-radius:5px;white-space:nowrap}.blueprint .flow-caption{background:#14283ff0;color:#f3f8ff;border-color:#45617b}.blueprint .flow-caption .poor{color:#7ab6ff}.blueprint .flow-caption .rich{color:#ff8393}

.astronomy{color:#5b6fd6}.blueprint #viewport{background:radial-gradient(ellipse at center,#183a65,#102845)}

/* subject groups in the sidebar */
.lesson-list{display:block}.subject{border:1px solid var(--line);border-radius:10px;margin-bottom:8px;background:#fff;overflow:hidden}.subject summary{list-style:none;cursor:pointer;display:flex;align-items:center;gap:9px;padding:11px 12px;font-size:12px;font-weight:650;letter-spacing:.9px;text-transform:uppercase;color:#3a4760}.subject summary::-webkit-details-marker{display:none}.subject summary::after{content:'›';margin-inline-start:auto;font-size:18px;color:#8194c0;transform:rotate(90deg);transition:transform .2s}.subject:not([open]) summary::after{transform:rotate(0)}.subject-dot{width:8px;height:8px;border-radius:50%;background:currentColor;opacity:.75}.subject.physics summary{color:#b8761f}.subject.chemistry summary{color:#2f7a70}.subject.biology summary{color:#b2415b}.subject.astronomy summary{color:#4c5fc7}.subject.geography summary{color:#4f8a3d}.subject.mathematics summary{color:#7a5cc2}.subject.history summary{color:#9a6a3a}.subject.economics summary{color:#b08a2c}.subject-count{font-size:11px;font-weight:600;color:#8c98ab;background:#f1f4f9;border-radius:10px;padding:2px 7px;margin-inline-start:4px}.subject .lesson{margin:0 6px 6px;width:calc(100% - 12px);padding:10px 8px}.subject .lesson.active:before{display:none}.subject .lesson small{display:none}.subject .lesson strong{margin-top:0}.coming-soon{margin:0 12px 12px;font-size:12px;color:#98a3b4;font-style:italic}
@media(max-width:1050px){.lesson-list{display:flex;gap:8px;overflow-x:auto;padding-bottom:4px}.subject{flex:0 0 auto;min-width:150px;margin-bottom:0}.subject .lesson{width:auto}.subject summary{padding:8px 10px}.subject[open]{min-width:170px}}

.lesson-symbol.mathematics{color:#7a5cc2}.lesson-symbol.geography{color:#4f8a3d}.lesson-symbol.history{color:#9a6a3a}.lesson-symbol.economics{color:#b08a2c}

/* full screen: 3D view + experiment controls side by side, filling the screen */
.workspace.is-full{position:fixed;inset:0;z-index:50;margin:0;padding:12px;gap:12px;background:#f6f8fb;display:grid;grid-template-columns:minmax(0,1fr) 340px;align-items:stretch;height:100vh;height:100dvh;width:100vw;box-sizing:border-box}
.workspace.is-full:fullscreen{width:100%;height:100%}
.workspace.is-full .model-panel{display:flex;flex-direction:column;min-height:0;height:100%}
.workspace.is-full .model-panel #viewport{flex:1 1 auto;height:auto;min-height:220px}
.workspace.is-full .control-panel{max-height:none;height:100%;overflow-y:auto;min-height:0}
.workspace.is-full .flow-guide{max-height:30vh;overflow:auto}
body.has-full{overflow:hidden}
.workspace.is-full #resetCamera{background:#3156d9;color:#fff;border-color:#3156d9;font-size:18px}
@media(max-width:760px){.workspace.is-full{grid-template-columns:1fr;grid-template-rows:minmax(0,1.2fr) minmax(0,1fr);padding:6px;gap:6px}.workspace.is-full .viewer-hint,.workspace.is-full .narration-strip{display:none}}

.choice-row{display:flex;flex-wrap:wrap;gap:6px}.choice{border:1px solid #e1e7f1;background:#f7f9fd;border-radius:6px;padding:6px 10px;font-size:12px;color:#5d6b82}.choice.selected{background:#edf1ff;border-color:#b9c8f7;color:var(--blue);font-weight:600}

/* ---------- search ---------- */
.lesson-search{position:relative;margin:0 0 10px}.lesson-search input{width:100%;border:1px solid #e1e7f1;background:#f7f9fd;border-radius:8px;padding:9px 30px 9px 30px;font-size:13px;color:#24324b;outline:none;transition:border-color .15s,background .15s}.lesson-search input:focus{border-color:#9fb4f5;background:#fff;box-shadow:0 0 0 3px #3156d91a}.lesson-search input::-webkit-search-cancel-button{cursor:pointer}.ls-icon{position:absolute;left:10px;top:50%;transform:translateY(-52%);font-size:16px;color:#8b97a9;pointer-events:none}.lesson-search kbd{position:absolute;right:8px;top:50%;transform:translateY(-50%);font:600 10px/1 'DM Sans',sans-serif;color:#95a1b3;border:1px solid #dfe5ef;border-radius:4px;padding:3px 5px;background:#fff;pointer-events:none}.lesson-search input:focus+kbd,.lesson-search input:not(:placeholder-shown)+kbd{display:none}
.search-results{margin:0 0 12px;font-size:12px}.search-results[hidden]{display:none}.sr-count{color:#7b889b;padding:2px 4px 6px;font-size:11px;letter-spacing:.3px}.sr-group{border:1px solid #e7ecf6;border-radius:8px;background:#fbfcff;padding:4px;margin-bottom:8px}.sr-label{font-size:10px;font-weight:650;letter-spacing:1px;color:#8793a6;text-transform:uppercase;padding:4px 6px 2px}.sr-item{display:block;width:100%;text-align:start;padding:6px 7px;border-radius:6px}.sr-item:hover,.sr-item:focus-visible{background:#eef2ff}.sr-item span{display:block;color:#2c3e66;font-weight:600;font-size:12px}.sr-item small{display:block;color:#8390a3;font-size:11px;line-height:1.45;margin-top:2px}
.lesson[hidden],details.subject[hidden]{display:none!important}
/* ---------- progress ---------- */
.progress-card{margin:-12px 0 16px;padding:10px 12px;border:1px solid #e7ecf6;border-radius:9px;background:#fbfcff}.pc-top{display:flex;justify-content:space-between;align-items:baseline;gap:8px;font-size:11px;color:#7b889b}.pc-top strong{font-size:12px;color:#2f4ea8;font-weight:650}.pc-bar{height:6px;border-radius:6px;background:#e9eef7;margin-top:8px;overflow:hidden}.pc-bar>div{height:100%;width:0;border-radius:6px;background:linear-gradient(90deg,#4f74ee,#22a06b);transition:width .4s}
.lesson{position:relative}.lesson-progress{position:absolute;inset-inline-end:8px;top:12px;width:18px;height:18px;display:grid;place-items:center;pointer-events:none}.lesson-progress:empty{display:none}.lesson-progress svg{display:block}.lp-check{width:18px;height:18px;border-radius:50%;background:#22a06b;color:#fff;font-size:11px;font-weight:700;display:grid;place-items:center;line-height:1}.lesson.is-done strong{color:#1f7a53}
.subject-count.all-done{background:#dcf5e8!important;color:#1b7a4c!important}
.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}
.lesson-header{flex-wrap:wrap}.lesson-progress-panel{display:flex;align-items:center;gap:12px;border:1px solid #dfe5ef;border-radius:8px;background:#fff;padding:7px 8px 7px 12px;margin-inline-start:auto;flex-shrink:0}.lpp-text{font-size:11px;color:#74849a;line-height:1.3}.lpp-text strong{display:block;font-size:13px;color:#2b3e67}.lpp-bar{width:70px;height:5px;border-radius:5px;background:#e9eef7;overflow:hidden}.lpp-bar>div{height:100%;width:0;background:#5b7cf0;border-radius:5px;transition:width .4s}.finish-button{font-size:12px;font-weight:600;border:1px solid #cfdaf7;background:#f4f7ff;color:#3156d9;border-radius:6px;padding:7px 11px;white-space:nowrap}.finish-button.done{background:#e6f7ee;border-color:#a8e0c2;color:#1b7a4c}
.reset-progress{margin-top:6px;color:#9aa5b5!important}
/* ---------- glossary ---------- */
.term{display:inline!important;height:auto!important;min-height:0!important;padding:0;margin:0;font:inherit;color:inherit;background:none;border:0;border-bottom:1.5px dotted #7d95e6;cursor:help;line-height:inherit;text-align:inherit;border-radius:0}.term:hover,.term:focus-visible{color:#3156d9;border-bottom-style:solid;filter:none}
.glossary-pop{position:fixed;z-index:60;background:#fff;border:1px solid #d8e2fb;border-radius:10px;box-shadow:0 12px 40px #1d37642e;padding:12px 14px 12px;color:#34435b;font-size:13px;line-height:1.65}.glossary-pop[hidden]{display:none}.gp-head{display:flex;justify-content:space-between;align-items:center;gap:10px}.gp-head strong{font-size:14px;color:#1f3a8a}.gp-close{font-size:20px;line-height:1;color:#8391a7;width:26px;height:26px;border-radius:6px}.gp-close:hover{background:#f1f4fa}.glossary-pop p{margin:6px 0 0}.gp-lesson{margin-top:8px;font-size:12px;font-weight:600;color:#3156d9;padding:4px 0}
@media(max-width:760px){.lesson-progress-panel{margin-inline-start:0;width:100%;justify-content:space-between}.lpp-bar{flex:1}}
.lesson-progress{top:17px;inset-inline-end:7px}.lesson:has(.lesson-progress:not(:empty)) .lesson-arrow{visibility:hidden}
.viewer-buttons{display:flex;gap:8px;align-items:center}#resetView{font-size:19px}#resetView.spin{animation:resetSpin .45s ease}@keyframes resetSpin{from{transform:rotate(0)}to{transform:rotate(360deg)}}.workspace.is-full #resetView{background:#fff}

/* ---------- clean scene labels (HTML overlay) ---------- */
.label-layer{position:absolute;inset:0;z-index:2;pointer-events:none;overflow:hidden}
.scene-label{position:absolute;left:0;top:0;display:inline-flex;align-items:center;gap:6px;max-width:360px;padding:4px 9px 4px 7px;border-radius:999px;background:rgba(15,23,42,.78);-webkit-backdrop-filter:blur(6px);backdrop-filter:blur(6px);border:1px solid rgba(255,255,255,.14);box-shadow:0 2px 10px rgba(2,8,23,.25);color:#f8fafc;font:600 11.5px/1.25 'DM Sans',system-ui,sans-serif;letter-spacing:.1px;white-space:nowrap;transition:opacity .2s;will-change:transform}
.scene-label i{flex:0 0 7px;height:7px;border-radius:50%;background:var(--dot,#60a5fa);box-shadow:0 0 0 2px rgba(255,255,255,.12)}
.scene-label span{overflow:hidden;text-overflow:ellipsis}
.scene-label.mono{font-family:'SFMono-Regular',Consolas,'Courier New',monospace;font-weight:600;letter-spacing:.6px;border-radius:6px}
.blueprint .scene-label{background:rgba(10,37,64,.85);border-color:rgba(142,205,244,.35)}
.workspace.is-full .scene-label{font-size:12.5px}
@media(max-width:760px){.scene-label{font-size:10.5px;padding:3px 8px 3px 6px;max-width:180px}}

/* Sidebar: show only the lesson name. The short description is still in the markup, so search keeps finding lessons by it; delete this rule to bring it back. */
.lesson-list .lesson em{display:none}

/* Playback bar: the title and the status sentence share one row above the timeline, across the
   full width, instead of being squeezed into a 145px column beside the play button. */
.playback{display:grid;grid-template-columns:auto auto minmax(0,1fr) auto;grid-template-rows:auto auto;column-gap:10px;row-gap:9px;align-items:center}
.playback #playPause{grid-column:1;grid-row:1/3}
.playback #resetSimulation{grid-column:2;grid-row:1/3}
.playback .playback-label{grid-column:3/5;grid-row:1;max-width:none;min-width:0;display:flex;align-items:baseline;gap:12px}
.playback .playback-label strong{flex:none;white-space:nowrap}
.playback .timeline{grid-column:3;grid-row:2;margin-inline:0}
.playback .speed-label{grid-column:4;grid-row:2}
.playback .status-clip{display:block;flex:1;min-width:0;margin-top:0;overflow:hidden}
.playback .status-clip #animationStatus{display:inline-block;margin-top:0;white-space:nowrap;will-change:transform;transition:opacity .3s}
.playback .status-clip.is-overflowing{-webkit-mask-image:linear-gradient(to right,#000 calc(100% - 32px),transparent);mask-image:linear-gradient(to right,#000 calc(100% - 32px),transparent)}
[dir=rtl] .playback .status-clip.is-overflowing{-webkit-mask-image:linear-gradient(to left,#000 calc(100% - 32px),transparent);mask-image:linear-gradient(to left,#000 calc(100% - 32px),transparent)}
.playback .status-clip.is-overflowing.is-scrolled{-webkit-mask-image:linear-gradient(to right,transparent,#000 24px,#000 calc(100% - 32px),transparent);mask-image:linear-gradient(to right,transparent,#000 24px,#000 calc(100% - 32px),transparent)}

/* Lambda Lab logo in the top bar (replaces the old blue λ square) */
.brand-logo{display:block;height:46px;width:auto;flex:none}
@media(max-width:760px){.brand-logo{height:40px}}

/* ---- Sidebar lesson rows: one even, symmetric grid for every lesson ----
   icon | name (vertically centred, never cut off) | status slot (arrow, ring or tick, always in the same place) */
@media(min-width:1251px){.app-layout{grid-template-columns:256px minmax(0,1fr)}}
@media(min-width:1051px){
 .subject .lesson-list{padding:2px 0 4px}
 .subject .lesson{display:grid;grid-template-columns:34px minmax(0,1fr) 16px;align-items:center;column-gap:10px;
  min-height:58px;margin:0 4px 4px;width:calc(100% - 8px);padding:8px 8px 8px 9px;border-radius:10px;
  transition:background .15s,border-color .15s}
 .subject .lesson>*{grid-row:1}
 .subject .lesson:hover:not(.active){background:#f6f8fc}
 .subject .lesson .lesson-symbol{grid-column:1;width:34px;height:34px;flex:none;margin:0;border-radius:10px;font-size:19px;
  border:1px solid #e6eaf2;background:#fbfcfe;box-shadow:0 1px 2px #1a2a4a0d}
 .subject .lesson.active .lesson-symbol{background:#fff;border-color:#d3ddfb}
 .subject .lesson>span:nth-child(2){grid-column:2;min-width:0;display:flex;align-items:center}
 .subject .lesson strong{margin:0;font-size:13.5px;line-height:1.32;font-weight:650;overflow-wrap:anywhere}
 .subject .lesson .lesson-arrow,.subject .lesson .lesson-progress{grid-column:3;justify-self:center;align-self:center}
 .subject .lesson .lesson-arrow{margin:0;font-size:18px;line-height:1;color:#a3b0c9}
 .subject .lesson.active .lesson-arrow{color:var(--blue)}
 .subject .lesson .lesson-progress{position:static;inset:auto;width:16px;height:16px}
 .subject .lesson .lesson-progress svg{width:16px;height:16px}
 .subject .lesson:has(.lesson-progress:not(:empty)) .lesson-arrow{display:none}
}
.subject-dot{flex:none}

/* ---- Lesson drawer: hidden sidebar that slides out from the arrow in the top bar ---- */
.topbar-start{display:flex;align-items:center;gap:14px;min-width:0}
.library-toggle{display:none}
@media(min-width:1051px){
 .app-layout{grid-template-columns:minmax(0,1fr)!important}
 .topbar{position:relative;z-index:70}
 .library-toggle{display:grid;place-items:center;flex:none;width:40px;height:40px;padding:0;border:1px solid var(--line);border-radius:12px;
  background:#fff;color:#3a4760;cursor:pointer;box-shadow:0 1px 2px #1a2a4a0f;transition:background .2s,border-color .2s,color .2s,box-shadow .2s}
 .library-toggle:hover{background:#f3f6fd;border-color:#d3ddfb;color:var(--blue)}
 .library-toggle:focus-visible{outline:none;box-shadow:0 0 0 3px #3156d933}
 .library-toggle svg{transition:transform .38s cubic-bezier(.22,.8,.24,1)}
 body.library-open .library-toggle{background:#f0f4ff;border-color:#d3ddfb;color:var(--blue)}
 body.library-open .library-toggle svg{transform:rotate(180deg)}
 [dir=rtl] .library-toggle svg{transform:scaleX(-1)}
 [dir=rtl] body.library-open .library-toggle svg{transform:scaleX(-1) rotate(180deg)}
 .library{position:fixed;top:84px;bottom:0;inset-inline-start:0;width:288px;z-index:60;overflow-y:auto;overscroll-behavior:contain;
  padding:26px 16px 24px;border-inline-end:1px solid var(--line);transform:translateX(-100%);visibility:hidden;box-shadow:none}
 [dir=rtl] .library{transform:translateX(100%)}
 body.library-ready .library{transition:transform .42s cubic-bezier(.22,.8,.24,1),box-shadow .42s,visibility 0s linear .42s}
 body.library-open .library{transform:none;visibility:visible;box-shadow:14px 0 44px #0f1c3a24;transition:transform .42s cubic-bezier(.22,.8,.24,1),box-shadow .42s,visibility 0s}
 [dir=rtl] body.library-open .library{box-shadow:-14px 0 44px #0f1c3a24}
 body.library-open .library>*{animation:libraryIn .45s cubic-bezier(.22,.8,.24,1) both}
 body.library-open .library>:nth-child(2){animation-delay:.04s}
 body.library-open .library>:nth-child(3){animation-delay:.08s}
 body.library-open .library>:nth-child(4){animation-delay:.12s}
 body.library-open .library>:nth-child(5){animation-delay:.16s}
 body.library-open .library>:nth-child(n+6){animation-delay:.2s}
 .library-backdrop{position:fixed;inset:84px 0 0 0;z-index:55;background:#0f1c3a;opacity:0;pointer-events:none;transition:opacity .35s}
 body.library-open .library-backdrop{opacity:.16;pointer-events:auto}
}
@keyframes libraryIn{from{opacity:0;transform:translateX(-14px)}to{opacity:1;transform:none}}
[dir=rtl] body.library-open .library>*{animation-name:libraryInRtl}
@keyframes libraryInRtl{from{opacity:0;transform:translateX(14px)}to{opacity:1;transform:none}}
@media(prefers-reduced-motion:reduce){.library,.library-toggle svg,.library-backdrop{transition:none!important}body.library-open .library>*{animation:none!important}}

/* ---- Live lesson card: a flat info card stuck to the right edge of the 3D viewer (Light & colour) ---- */
.lab-card{position:absolute;top:64px;right:12px;bottom:12px;z-index:6;width:292px;max-width:calc(100% - 24px);display:flex;align-items:flex-start;pointer-events:none;
 transition:transform .38s cubic-bezier(.22,.8,.24,1)}
.lab-card[hidden]{display:none}
.lab-card-body{pointer-events:auto;width:100%;max-height:100%;overflow:auto;overscroll-behavior:contain;background:rgba(255,255,255,.94);backdrop-filter:blur(8px);
 border:1px solid var(--line);border-radius:14px;box-shadow:0 10px 30px #1a2a4a1f;padding:14px 16px 12px;font-size:12.5px;color:#24324b;line-height:1.45;
 transition:opacity .25s,transform .38s cubic-bezier(.22,.8,.24,1)}
.lab-card-toggle{pointer-events:auto;flex:none;width:26px;height:44px;margin:12px -1px 0 0;border:1px solid var(--line);border-right:0;border-radius:10px 0 0 10px;
 background:#fff;color:#51607a;cursor:pointer;display:grid;place-items:center;font-size:18px;box-shadow:-4px 4px 12px #1a2a4a14}
.lab-card-toggle span{transition:transform .3s}
.lab-card-toggle:hover{color:var(--blue)}
.lab-card.is-folded{transform:translateX(calc(100% - 26px))}
.lab-card.is-folded .lab-card-body{opacity:0;pointer-events:none}
.lab-card.is-folded .lab-card-toggle span{transform:rotate(180deg)}
.lab-card.is-flash .lab-card-body{box-shadow:0 0 0 3px #3156d955,0 10px 30px #1a2a4a1f}
.lab-card h4{margin:2px 0 4px;font-size:12px;letter-spacing:.7px;text-transform:uppercase;color:#1f2d45}
.lab-card h4:not(:first-child){margin-top:14px;padding-top:12px;border-top:1px solid var(--line)}
.lab-card-sub{margin:0 0 8px;color:#6b7890;font-size:11.5px}
.lab-strip{display:flex;height:16px;border-radius:5px;overflow:hidden;border:1px solid #e3e8f0}
.lab-strip i{flex:1}
.lab-strip-scale{display:flex;justify-content:space-between;font-size:10.5px;color:#8591a5;margin:3px 0 6px}
.lab-card dl{display:grid;grid-template-columns:1fr auto;gap:3px 10px;margin:4px 0 0}
.lab-card dt{color:#6b7890}.lab-card dd{margin:0;font-weight:650;text-align:right;color:#1f2d45}
.lab-card-warn{margin:6px 0 0;color:#b4382b;font-weight:600}
.lab-chip{display:inline-grid;place-items:center;width:18px;height:18px;border-radius:5px;color:#fff;font-size:10.5px;font-weight:700;margin-left:4px}
.lab-objs{list-style:none;margin:6px 0 0;padding:0;display:grid;gap:6px}
.lab-objs li{display:grid;grid-template-columns:minmax(0,1fr) 58px 14px 50px;align-items:center;gap:7px}
.lab-obj{font-weight:650;color:#1f2d45;min-width:0}
.lab-obj small{display:block;font-weight:400;color:#8591a5;font-size:10.5px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.lab-bars{display:grid;gap:2px}
.lab-bar{position:relative;height:5px;border-radius:3px;background:#eef1f6;overflow:hidden}
.lab-bar b{position:absolute;left:0;top:0;bottom:0;border-radius:3px}
.lab-swatch{width:14px;height:14px;border-radius:50%;border:1px solid #cfd6e2}
.lab-looks{font-weight:650;font-size:11.5px;color:#1f2d45}
.lab-looks.is-black{color:#b4382b}
.lab-card-note{margin:10px 0 0;color:#8591a5;font-size:10.5px}
.workspace.is-full .lab-card{top:70px}
@media(max-width:760px){.lab-card{top:auto;height:62%;width:260px}}
.lab-card.is-wide{width:320px}
.lab-diagram-slot{margin:2px 0 8px;border-radius:10px;overflow:hidden;background:#1d2a24}
.lab-diagram{display:block;width:100%;height:auto}
.lab-card.is-off{display:none}
.lab-mbar{display:grid;grid-template-columns:1fr auto;gap:2px 8px;margin:6px 0 0;font-size:12px}
.lab-mbar span{color:#51607a}.lab-mbar b{color:#1f2d45}
.lab-mbar i{grid-column:1/-1;height:9px;border-radius:5px;background:#eef1f6;overflow:hidden;display:block}
.lab-mbar u{display:block;height:100%;border-radius:5px;text-decoration:none}
.lab-verdict{margin:9px 0 6px;font-weight:700;color:#b4382b}
.lab-verdict.is-ok{color:#1f7a53}
.lab-order{margin:0 0 4px;font-weight:650;color:#3156d9}
.lab-canvas-slot{margin:4px 0 10px;border-radius:10px;overflow:hidden;background:#0d1017}
.lab-canvas-slot.is-light{background:#fff;border:1px solid var(--line)}
.lab-canvas{display:block;width:100%;height:auto}
.lab-card{transition:transform .35s ease,width .3s ease}
.lab-card.is-broad{width:430px}
.lab-canvas-slot{cursor:zoom-in}
.lab-card.is-zoom{width:min(780px,calc(100% - 24px))}
.lab-card.is-zoom .lab-canvas-slot{cursor:zoom-out}
@media(max-width:760px){.lab-card.is-broad{width:300px}}
.lab-ebars{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;align-items:start;margin:8px 0 4px}
.lab-ebar{display:grid;justify-items:center;gap:4px;font-size:11px}
.lab-ebar i{position:relative;display:block;width:34px;height:150px;border-radius:6px;background:#eef1f6;overflow:hidden}
.lab-ebar u{position:absolute;left:0;right:0;bottom:0;border-radius:6px 6px 0 0;transition:height .08s linear}
.lab-ebar-val{font-weight:700;color:#1f2d45}.lab-ebar-name{color:#6b7890;text-align:center;line-height:1.2;min-height:2.4em}
/* ---------- lesson progress beside the controls; taller viewer ---------- */
.scene-badge{display:none}
.control-panel .lesson-progress-panel{margin:0 0 18px;width:100%;justify-content:space-between}
.control-panel .lesson-progress-panel .lpp-bar{flex:1}
@media(min-width:761px){.workspace:not(.is-full) .model-panel #viewport{height:525px}.workspace:not(.is-full) .control-panel{max-height:800px}}
@media(min-width:1700px){.workspace:not(.is-full) .model-panel #viewport{height:550px}}
/* ---------- size journey: card, caption and ladder ---------- */
.sc-here{margin:2px 0 10px}.sc-here em{display:block;font-style:normal;font-size:15px;font-weight:650;color:#3156d9}
.sc-here strong{display:block;font-size:30px;line-height:1.15;color:#1d2f59;letter-spacing:-.5px;margin-top:2px}.sc-here span{font-size:12px;color:#6b7890}
.sc-fact{font-size:13px;line-height:1.55;color:#34445f;margin:0 0 10px;padding:10px 12px;border-radius:10px;background:#f5f7fb}
.sc-compare{display:flex;align-items:center;gap:12px;margin:6px 0 10px}.sc-compare b{flex:none;font-size:22px;font-weight:700;color:#e0752f}.sc-compare span{font-size:12px;line-height:1.45;color:#56657d}
.sc-go{display:block;width:100%;margin:6px 0 4px;padding:9px 12px;border-radius:9px;border:1px solid #cfdaf7;background:#f4f7ff;color:#3156d9;font:inherit;font-size:12.5px;font-weight:650;cursor:pointer;text-align:left}
.sc-go:hover{background:#e9efff}
.sc-caption{position:absolute;left:12px;right:344px;bottom:78px;z-index:5;text-align:center;pointer-events:none;transition:opacity .35s}
.sc-caption.is-off{opacity:0}.sc-caption[hidden],.sc-ladder[hidden]{display:none}
.sc-caption strong{display:block;font-size:26px;font-weight:700;letter-spacing:-.4px;color:#18243c;text-shadow:0 1px 12px #ffffffcc}
.sc-caption span{display:inline-block;margin-top:4px;font-size:15px;font-weight:600;color:#3156d9;background:#ffffffd9;border-radius:999px;padding:3px 12px}
.sc-caption.is-dark strong{color:#fff;text-shadow:0 1px 12px #000c}.sc-caption.is-dark span{background:#ffffff26;color:#dbe6ff}
.sc-ladder{position:absolute;left:12px;right:344px;bottom:12px;z-index:6;display:flex;align-items:center;gap:8px;padding:6px;border-radius:14px;background:#ffffffe6;border:1px solid #dfe5ef;box-shadow:0 6px 20px #1a2a4a1a}
.sc-ladder.is-dark{background:#0d1426e6;border-color:#2a3654}
.sc-step{flex:none;padding:9px 12px;border-radius:10px;border:0;background:#3156d9;color:#fff;font:inherit;font-size:13px;font-weight:650;cursor:pointer;white-space:nowrap}
.sc-step:hover{background:#2849c2}
.sc-stops{flex:1;display:flex;justify-content:space-between;min-width:0;position:relative}
.sc-stops::before{content:"";position:absolute;left:10px;right:10px;top:9px;height:2px;background:#d5ddea}
.sc-ladder.is-dark .sc-stops::before{background:#34415f}
.sc-stop{position:relative;display:flex;flex-direction:column;align-items:center;gap:3px;border:0;background:none;padding:2px 2px;font:inherit;font-size:11px;font-weight:600;color:#6b7890;cursor:pointer;min-width:0}
.sc-stop i{width:12px;height:12px;border-radius:50%;background:#fff;border:2px solid #b7c3d6;margin-top:3px;transition:transform .25s,background .25s}
.sc-stop span{white-space:nowrap}.sc-stop:hover{color:#3156d9}
.sc-stop.is-past i{background:#9fb4ec;border-color:#9fb4ec}
.sc-stop.is-on i{background:#3156d9;border-color:#3156d9;transform:scale(1.35);box-shadow:0 0 0 4px #3156d933}.sc-stop.is-on{color:#3156d9}
.sc-ladder.is-dark .sc-stop{color:#9aa8c4}.sc-ladder.is-dark .sc-stop i{background:#0d1426;border-color:#4a5a80}
.sc-ladder.is-dark .sc-stop.is-past i{background:#5f78c0;border-color:#5f78c0}.sc-ladder.is-dark .sc-stop.is-on{color:#fff}.sc-ladder.is-dark .sc-stop.is-on i{background:#7d9bff;border-color:#7d9bff}
@media(max-width:1100px){.sc-stop span{font-size:9.5px}}
@media(max-width:760px){.sc-caption,.sc-ladder{right:12px}.sc-stop span{display:none}.sc-caption{bottom:66px}.sc-caption strong{font-size:20px}}
/* ---------- brain: reaction test card ---------- */
.br-test{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:4px;width:100%;min-height:118px;margin:4px 0 8px;border:0;border-radius:14px;cursor:pointer;font:inherit;color:#fff;background:#3156d9;transition:background .15s,transform .1s;user-select:none}
.br-test:active{transform:scale(.99)}.br-test strong{font-size:24px;font-weight:750;letter-spacing:-.3px}.br-test span{font-size:12px;opacity:.9}
.br-test[data-state="wait"]{background:#c62f2f}.br-test[data-state="go"]{background:#18a957}.br-test[data-state="early"]{background:#8a5a12}.br-test[data-state="result"]{background:#1f2d45}
.br-test[data-state="go"] strong{font-size:34px}
.br-results{font-size:12px;color:#56657d;margin:0 0 10px}.br-results div{display:flex;flex-wrap:wrap;gap:5px;margin-bottom:5px}
.br-results i{font-style:normal;font-weight:650;font-size:12px;padding:2px 8px;border-radius:999px;background:#eef2f9;color:#34445f}.br-results i.is-last{background:#3156d9;color:#fff}
.br-bar{display:flex;height:14px;border-radius:7px;overflow:hidden;margin:4px 0 8px}.br-bar i{display:block;min-width:2px}
.br-stages{list-style:none;margin:0 0 8px;padding:0}.br-stages li{display:flex;align-items:center;gap:8px;font-size:12px;color:#46546b;padding:3px 0}
.br-stages li i{flex:none;width:10px;height:10px;border-radius:3px}.br-stages li span{flex:1}.br-stages li b{color:#1f2d45}
.br-compare{font-size:12.5px;line-height:1.5;color:#46546b;margin:6px 0 2px}.br-compare b{color:#1f2d45}
/* ---------- world map: timeline and card ---------- */
.wm-timeline{position:absolute;left:12px;right:344px;bottom:12px;z-index:6;display:flex;align-items:center;gap:10px;padding:8px 10px;border-radius:14px;background:#ffffffeb;border:1px solid #dfe5ef;box-shadow:0 6px 20px #1a2a4a1a}
.wm-timeline[hidden]{display:none}
.wm-step{flex:none;width:34px;height:34px;border-radius:10px;border:0;background:#3156d9;color:#fff;font:inherit;font-size:13px;cursor:pointer}.wm-step:hover{background:#2849c2}
.wm-track{position:relative;flex:1;height:44px;min-width:0}
.wm-track input{position:absolute;left:0;right:0;top:6px;width:100%;margin:0;accent-color:#3156d9;cursor:pointer}
.wm-ticks{position:absolute;left:8px;right:8px;top:0;bottom:0;pointer-events:none}
.wm-ticks i{position:absolute;top:22px;width:4px;height:8px;margin-left:-2px;border-radius:2px;background:#b7c3d6}.wm-ticks i.is-on{background:#e0752f;height:12px;top:20px}
.wm-ticks em{position:absolute;top:31px;transform:translateX(-50%);font-style:normal;font-size:10px;color:#7a879b}
.wm-year{flex:none;min-width:92px;text-align:center}.wm-year strong{display:block;font-size:22px;font-weight:750;color:#1d2f59;line-height:1}.wm-year span{font-size:10px;color:#7a879b}
@media(max-width:760px){.wm-timeline{right:12px}.wm-ticks em{display:none}}
.wm-cap{font-size:13px;line-height:1.55;color:#34445f;margin:0 0 10px}
.wm-hint{font-size:12px;color:#7a879b;margin:4px 0 10px}
.wm-sel{position:relative;padding:10px 12px;border-radius:10px;background:#f4f7ff;border:1px solid #d6e0fa;margin:0 0 10px}.wm-sel strong{display:block;font-size:15px;color:#1d2f59}.wm-sel span{display:block;font-size:12px;color:#56657d;margin-top:2px}
.wm-sel button{position:absolute;top:8px;right:8px;border:0;background:none;color:#3156d9;font:inherit;font-size:11.5px;font-weight:650;cursor:pointer}
.wm-rows{display:flex;flex-direction:column;gap:4px;margin:4px 0 8px}
.wm-row{position:relative;display:flex;align-items:center;gap:8px;width:100%;padding:6px 8px 9px;border:1px solid transparent;border-radius:8px;background:none;font:inherit;font-size:12.5px;color:#34445f;cursor:pointer;text-align:left}
.wm-row:hover,.wm-row.is-on{background:#f4f7ff;border-color:#d6e0fa}.wm-row i{flex:none;width:11px;height:11px;border-radius:3px}.wm-row span{flex:1;min-width:0}.wm-row b{font-weight:650;color:#1f2d45;white-space:nowrap}
.wm-row u{position:absolute;left:8px;bottom:3px;height:3px;border-radius:2px;opacity:.7}
/* world map: name of the country under the pointer */
.wm-tip{position:absolute;left:0;top:0;z-index:6;pointer-events:none;max-width:260px;padding:6px 10px;border-radius:9px;background:rgba(24,31,43,.92);color:#fff;font:600 13px/1.25 Inter,system-ui,sans-serif;box-shadow:0 6px 18px rgba(15,23,42,.22);white-space:nowrap}
.wm-tip span{display:block;margin-top:2px;font-weight:500;font-size:11.5px;color:#c7d2e3}
.wm-tip[hidden]{display:none}
/* rocket lesson: launch bar along the bottom of the viewer */
.rk-bar{position:absolute;left:12px;right:344px;bottom:12px;z-index:6;display:flex;align-items:center;gap:10px;padding:8px 10px;border-radius:14px;background:#ffffffeb;border:1px solid #dfe5ef;box-shadow:0 6px 20px #1a2a4a1a}
.rk-bar[hidden]{display:none}
.rk-bar button{flex:none;height:38px;padding:0 16px;border-radius:11px;border:0;font:inherit;font-weight:700;cursor:pointer}
.rk-launch{background:linear-gradient(135deg,#ff6a3d,#e0302a);color:#fff;box-shadow:0 4px 14px #e0302a40}
.rk-launch:hover{filter:brightness(1.06)}
.rk-back{background:#eef2f8;color:#23304a}
.rk-back:disabled{opacity:.45;cursor:default}
.rk-clock{display:flex;flex-direction:column;line-height:1.15;margin-left:6px}
.rk-clock strong{font-size:18px;font-variant-numeric:tabular-nums;color:#16213a}
.rk-clock span{font-size:12px;color:#5b6780}
.rk-warp{margin-left:auto;font-size:12px;color:#5b6780;font-variant-numeric:tabular-nums}
.rk-flash{position:absolute;inset:0;z-index:5;background:#fff;opacity:0;pointer-events:none;transition:opacity .45s}
.rk-flash.is-on{opacity:.85;transition:none}
.rk-grid{display:grid;grid-template-columns:1fr auto;gap:4px 12px;margin:6px 0 10px;font-size:13px}
.rk-grid span{color:#5b6780}.rk-grid b{text-align:right;color:#16213a;font-variant-numeric:tabular-nums}
.rk-grid b.rk-bad{color:#c62828}.rk-grid b.rk-warn{color:#b26a00}
.rk-meter{position:relative;height:10px;border-radius:6px;background:#e9edf4;margin:18px 0 12px}
.rk-meter i{position:absolute;left:0;top:0;bottom:0;border-radius:6px;background:linear-gradient(90deg,#4f7fe0,#35b36b)}
.rk-meter i.is-low{background:linear-gradient(90deg,#f0a64a,#e0574a)}
.rk-meter em{position:absolute;top:-17px;transform:translateX(-50%);font-size:10.5px;font-style:normal;color:#35507f;white-space:nowrap}
.rk-meter em::after{content:'';position:absolute;left:50%;top:15px;width:1px;height:14px;background:#35507f}
.rk-meter em.is-esc{color:#7a3fb0;top:13px}.rk-meter em.is-esc::after{top:-4px;height:6px}.rk-meter em.is-esc::after{background:#7a3fb0}
.rk-result{margin:8px 0 10px;padding:10px 12px;border-radius:12px;background:#f3f5f9;border-left:4px solid #8a94a8;font-size:13px;line-height:1.4}
.rk-result strong{display:block;font-size:15px;margin-bottom:3px;color:#16213a}
.rk-result.is-orbit{background:#eaf7ef;border-color:#2e9e5b}.rk-result.is-escape{background:#f2ecfb;border-color:#7a3fb0}
.rk-result.is-crash,.rk-result.is-burnup,.rk-result.is-heavy{background:#fdecea;border-color:#d64533}.rk-result.is-suborbital{background:#fff5e5;border-color:#e39b2d}
.rk-best{font-size:13px;padding:8px 10px;border-radius:10px;background:#fff8e1;color:#4a3b00}
.rk-best em{font-style:normal;font-weight:700;color:#c25e00;margin-left:6px}
@media (max-width:760px){.rk-bar{right:12px;flex-wrap:wrap}}
.rk-down{font-style:normal;font-weight:600;color:#b26a00}
/* immune lesson: tools along the bottom of the viewer */
.im-bar{position:absolute;left:12px;right:344px;bottom:12px;z-index:6;display:flex;flex-wrap:wrap;align-items:center;gap:8px 10px;padding:8px 10px;border-radius:14px;background:#ffffffeb;border:1px solid #dfe5ef;box-shadow:0 6px 20px #1a2a4a1a}
.im-bar[hidden]{display:none}
.im-bar button{flex:none;height:34px;padding:0 9px;border-radius:10px;border:0;font:inherit;font-size:12.5px;font-weight:700;cursor:pointer}
.im-go{background:linear-gradient(135deg,#3f6ee8,#2447c2);color:#fff}.im-go:disabled{opacity:.6;cursor:default}
.im-vac{background:#eaf6ef;color:#1f7a45}.im-vac:disabled{opacity:.55;cursor:default}
.im-tools{display:flex;gap:6px}
.im-tools button{background:#f1f4f9;color:#23304a;display:flex;align-items:center;gap:6px;border:2px solid transparent}
.im-tools button small{font-weight:600;color:#6b7891;font-size:11px}
.im-tools button.is-on{border-color:#3156d9;background:#eef2ff}
.im-tools button.is-locked{opacity:.5}
.im-dot{width:12px;height:12px;border-radius:50%;display:inline-block}.im-dot.n{background:#b9a6e0}.im-dot.m{background:#d9b88f}.im-dot.a{background:#f2c94c}
.im-meters{display:flex;flex-direction:column;gap:3px;flex:1 1 110px;min-width:100px}
.im-meters span{display:flex;align-items:center;gap:6px;font-size:10.5px;color:#5b6780}
.im-meters em{font-style:normal;width:58px}
.im-meters b{flex:1;height:7px;border-radius:4px;background:#e6eaf1;overflow:hidden;min-width:60px}
.im-meters i{display:block;height:100%;background:#5b7fe6;transition:width .2s}.im-meters i.im-ab{background:#e2b53a}
.im-msg{position:absolute;left:10px;bottom:calc(100% + 6px);max-width:calc(100% - 20px);font-size:12.5px;color:#6b3b00;background:#fff6dc;border:1px solid #f3dd9b;padding:5px 10px;border-radius:9px;box-shadow:0 4px 12px #1a2a4a14}.im-msg:empty{display:none}
.im-chart{width:100%;height:auto;display:block;margin:4px 0 2px}
.rk-grid small{font-weight:500;color:#8b97ab}
@media (max-width:760px){.im-bar{right:12px}}
/* three-way language switch in the header */
.language-switch{display:inline-flex;padding:3px;border-radius:999px;background:#eef2f8;border:1px solid #dfe5ef;direction:ltr}
.language-switch button{border:0;background:transparent;font:inherit;font-size:12.5px;font-weight:700;color:#5b6780;padding:5px 11px;border-radius:999px;cursor:pointer;line-height:1.2}
.language-switch button[lang=ar]{font-family:'Noto Sans Arabic','DM Sans',sans-serif;font-size:13px}
.language-switch button.is-on{background:#fff;color:#1d2f59;box-shadow:0 1px 4px #1a2a4a22}
.language-switch button:hover:not(.is-on){color:#1d2f59}
.ear-strip{width:100%;height:auto;display:block;margin:4px 0 2px}

/* leader from a part's name tag to the exact particle (atom lesson) */
.part-pointer{position:absolute;inset:0;pointer-events:none;z-index:4}.part-pointer[hidden]{display:none}
.part-pointer .pp-line{position:absolute;height:2px;margin-top:-1px;background:#3156d9;transform-origin:0 50%;border-radius:1px;box-shadow:0 0 0 1px rgba(255,255,255,.7)}
.part-pointer .pp-dot{position:absolute;width:12px;height:12px;margin:-6px 0 0 -6px;border-radius:50%;border:2px solid #fff;background:#3156d9;box-shadow:0 0 0 3px rgba(49,86,217,.35),0 1px 4px rgba(0,0,0,.3)}

/* Chemistry Hub link in the lesson sidebar */
.hub-link{display:grid;grid-template-columns:auto 1fr;grid-template-rows:auto auto;column-gap:10px;align-items:center;margin:4px 0 12px;padding:10px 12px;border-radius:14px;text-decoration:none;color:#0f172a;
 background:linear-gradient(135deg,rgba(47,91,234,.12),rgba(124,58,237,.12));border:1px solid rgba(124,58,237,.22);transition:transform .15s,box-shadow .15s}
.hub-link:hover{transform:translateY(-1px);box-shadow:0 8px 20px rgba(79,70,229,.15)}
.hub-link>span:first-child{grid-row:1/3;font-size:22px}
.hub-link>span:nth-child(2){font-weight:750;font-size:14px}
.hub-link small{font-size:12px;color:#64748b}
.h-btn.chem{background:linear-gradient(135deg,#2f5bea,#7c3aed);color:#fff;border-color:transparent}

.h-btn.phys{background:linear-gradient(135deg,#0ea5e9,#2563eb);color:#fff;border-color:transparent}
.hub-link.phys{margin-top:-4px}