.teaching-scene { justify-content:center; gap:clamp(14px,2vh,24px); }
.ps-scene.ps-narrow > h1,.ps-scene.ps-narrow > h2,.ps-scene.ps-narrow > .ps-lead,.ps-scene.ps-narrow > .ps-body {max-width:100%;}
.teaching-scene > .ps-body {width:100%;align-self:stretch;}
.teaching-scene h2 { font-size:clamp(30px,3.1vw,48px); }
.teaching-scene .ps-body { font-size:clamp(20px,1.8vw,28px); line-height:1.65; }
.teaching-scene .ps-equation { font-size:clamp(23px,2.1vw,34px); overflow-x:auto; max-width:100%; }
.teaching-insight { border-left:4px solid var(--ps-accent,#147d78); padding:12px 20px; background:var(--ps-accent-soft,#f0f6fa); }
.teaching-caption {font-size:17px;line-height:1.5;color:var(--ps-soft,#5d677c);}
.calculation-player {width:100%;}
.calculation-stage {min-height:290px; display:flex; flex-direction:column; justify-content:center; gap:22px;}
.calculation-stage h3 {font-size:28px;}
.calculation-stage .calculation-equation {font-size:clamp(23px,2.4vw,36px);overflow-x:auto;}
.calculation-stage p {font-size:clamp(20px,1.8vw,28px);line-height:1.6;}
.calculation-controls {display:flex;flex-wrap:wrap;align-items:center;gap:12px;margin-top:14px;}
.calculation-controls label {display:flex;align-items:center;gap:12px;font-size:19px;}
.calculation-controls button:disabled {opacity:.45;cursor:default;}
.calculation-counter {font-size:20px;font-variant-numeric:tabular-nums;}
.calculation-stage.is-changing {animation:calculation-arrive .32s ease-out;}
@keyframes calculation-arrive {from{opacity:.3;transform:translateY(10px)}to{opacity:1;transform:translateY(0)}}
.transform-lab {display:grid;grid-template-columns:minmax(0,1.2fr) minmax(0,1fr);gap:24px;width:100%;align-items:center;}
.transform-lab canvas {width:100%;height:auto;display:block;border:1px solid #dae1eb;background:#fff;}
.transform-lab select {font:inherit;padding:7px;margin:0 0 8px 12px;}
.transform-math {font-size:clamp(20px,1.7vw,27px);line-height:1.5;}
.cofactor-lab {display:grid;grid-template-columns:280px minmax(0,1fr);gap:40px;align-items:center;}
.cofactor-matrix {display:grid;grid-template-columns:repeat(3,1fr);gap:10px;border-left:3px solid #172033;border-right:3px solid #172033;padding:14px;}
.cofactor-matrix button {font-size:32px;min-height:66px;border:2px solid #d7dfed;background:#eaf4f2;color:#172033;border-radius:8px;cursor:pointer;}
.cofactor-matrix button.removed {background:#f2f2f2;color:#777;text-decoration:line-through;}
.cofactor-matrix button.selected {outline:3px solid #3858d6;outline-offset:2px;}
.cofactor-result {font-size:clamp(24px,2.2vw,34px);line-height:1.8;}
.teaching-slide .ps-context-brief,.teaching-slide .ps-concept-path {display:none;}
@media(max-width:800px){.transform-lab,.cofactor-lab{grid-template-columns:1fr}.teaching-scene{justify-content:flex-start;overflow-y:auto}.cofactor-matrix{max-width:280px}.calculation-stage{min-height:220px}}
@media(max-height:760px){.teaching-scene{justify-content:flex-start;overflow-y:auto}.calculation-stage{min-height:230px}.teaching-scene .ps-body{font-size:21px}}
@media(prefers-reduced-motion:reduce){.calculation-stage.is-changing{animation:none}}
.ps-scene:has(#vecU1) {overflow-y:auto;justify-content:flex-start;}
.ps-scene:has(#vecU1) .ps-slider-row {padding-block:8px;min-height:44px;}
.ps-scene:has(#vecU1) .vec-mode-option {padding-block:7px;min-height:48px;}
.ps-scene:has(#vecU1) .ps-stack {gap:8px;}
.ps-classification-flow {min-width:0;max-width:100%;}
.ps-classification-flow .ps-equation {min-width:0;max-width:100%;overflow-x:auto;}
.ps-classification-flow .ps-card h3,.ps-classification-flow .ps-card p {white-space:normal;overflow-wrap:anywhere;}
.ps-classification-flow .ps-card .katex {font-size:.95em;}

/* Worked answers are separate from the task so students can reason first. */
.course-solution {width:100%;border-top:2px solid var(--ps-line,#d7dfed);padding-top:14px;font-size:clamp(19px,1.65vw,26px);line-height:1.6;text-align:left;}
.course-solution summary {width:fit-content;cursor:pointer;font-weight:750;color:var(--ps-accent-deep,#11695e);padding:8px 12px;}
.course-solution summary:focus-visible {outline:3px solid var(--ps-accent,#147d78);outline-offset:4px;}
.course-solution > :not(summary) {margin-top:14px;}
.course-solution .ps-equation {font-size:clamp(21px,1.9vw,30px);}
.ps-scene:has(.course-solution[open]) {justify-content:flex-start;overflow-y:auto;}
.teaching-scene > *, .ps-scene:has(.course-solution[open]) > * {flex-shrink:0;}
.ps-scene:has(.course-solution[open]) {gap:14px;}
.course-solution .ps-body {font-size:clamp(20px,1.65vw,26px);line-height:1.55;}
.ps-scene:has(.course-solution[open]) .ps-equation {padding-block:14px;}
.course-questions {width:100%;text-align:left;font-size:clamp(20px,1.8vw,28px);line-height:1.65;padding-left:1.35em;margin:0;}
.course-questions li+li {margin-top:12px;}
.ps-slide[data-role="definition"] .teaching-insight {border-left-color:var(--ps-accent,#147d78);}
@media(max-height:800px){.ps-scene:has(.course-questions),.ps-scene:has(.course-solution){justify-content:flex-start;overflow-y:auto;}}
.ps-guide-path button {display:flex;flex-direction:column;gap:4px;flex:1;border:0;background:none;color:inherit;text-align:left;font:inherit;cursor:pointer;padding:4px;}
.ps-guide-path button small {font-size:12px;font-weight:600;}
.ps-guide-path button:focus-visible {outline:2px solid var(--ps-accent);}
.ps-guide-path {grid-template-columns:1fr;gap:0;}
.ps-guide-path li {grid-template-columns:30px minmax(0,1fr);align-items:center;min-height:60px;border:0;border-bottom:1px solid var(--ps-line);border-radius:0;}
.ps-guide-path li:not(:last-child)::after {display:none;}