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.stage[data-scene="power"] .cycle-findings{display:grid;gap:.32cqw;margin:.45cqw 0;color:#684d35}
.stage[data-scene="power"] .cycle-finding{font:1.25cqw/1.42 var(--sans);margin:0;padding-left:.5cqw;border-left:2px solid #b65a3b}
.stage[data-scene="power"] .mechanism-copy .state-tags{margin-top:.75cqw;padding-top:.55cqw;gap:.5cqw .85cqw}
.stage[data-scene="power"] .mechanism-copy .state-tags div{font-size:1.16cqw;gap:.2cqw;color:#806747}
.stage[data-scene="power"] .mechanism-copy .state-tags strong{font-size:1.48cqw;color:#383b33}
.stage[data-scene="power"] .mechanism-copy .conclusion{font-size:1.28cqw;line-height:1.42;margin:.42cqw 0;padding-top:.42cqw}
.stage[data-scene="power"] .energy-chain{font-size:1.48cqw;gap:.35cqw;margin-top:.45cqw}
.stage[data-scene="power"] .energy-chain i{font-size:1.55cqw}
.stage[data-scene="stroke"] .mechanism-copy{width:40%}
.stage[data-scene="stroke"] .mechanism-copy .conclusion{white-space:pre-line;font-size:1.42cqw;line-height:1.5}
.stage[data-scene="linkage"] .cycle-findings{display:grid;gap:.42cqw;margin:.7cqw 0;color:#684d35}
.stage[data-scene="linkage"] .cycle-finding{font:1.42cqw/1.48 var(--sans);margin:0;padding-left:.5cqw;border-left:2px solid #b65a3b}
.family-copy .family-energy{max-width:100%;font:1.38cqw/1.6 var(--serif);color:#9b4b30;border-top:1px solid #bfa47a88;padding-top:.9cqw;margin:1.2cqw 0 0}
.family-copy h1{font-size:3.75cqw;line-height:1.3}
  .heat-definition-page{position:absolute;inset:14% 7% 10%;display:flex;flex-direction:column;justify-content:center;gap:2.2cqw}
  .heat-definition-heading span{display:block;color:#9b4b30;font:1.25cqw var(--sans);letter-spacing:.18em;margin-bottom:.55cqw}
  .heat-definition-heading h1{font:3.35cqw/1.2 var(--serif);font-weight:400;margin:0;color:var(--ink)}
  .heat-types{display:grid;grid-template-columns:repeat(4,1fr);gap:1cqw}
  .heat-types div{min-height:7cqw;display:flex;flex-direction:column;justify-content:center;padding:1.2cqw 1.1cqw;border-top:1px solid #bfa47a88;border-bottom:1px solid #bfa47a55;background:linear-gradient(135deg,#fffaf0a8,#e9dfca44);font:1.85cqw/1.3 var(--serif);color:#302e29}
  .heat-types div:first-child{border-left:2px solid #ad5034}.heat-types div:last-child{border-right:2px solid #ad5034}
  .heat-types small{font:1.05cqw/1.5 var(--sans);color:#8d8069;margin-top:.45cqw}
  .heat-common{display:flex;align-items:center;gap:2cqw;border-left:2px solid #ad5034;padding:.4cqw 1.3cqw}
  .heat-common span{font:1.3cqw var(--sans);color:#9b4b30;letter-spacing:.12em}
  .heat-common p{font:2.3cqw/1.35 var(--serif);margin:0;color:#302e29}.heat-common b,.heat-definition-statement b{color:#9b4b30;font-weight:500}
  .heat-definition-statement{margin:0;padding:1.15cqw 1.45cqw;background:#e9dfca62;border-left:2px solid #ad5034;font:1.8cqw/1.6 var(--serif);color:#4d4337}
  .model-hover-detail{width:100%;margin-top:1.3cqw;padding:1.05cqw 1.25cqw;background:linear-gradient(105deg,#fffaf0d9,#eee4d2aa);border-left:.24cqw solid #ad5034;box-shadow:0 .5cqw 1.6cqw #493b200c;color:#302e29}
  .model-hover-detail small{display:block;color:#9b4b30;font-size:.88cqw;letter-spacing:.15em}
  .model-hover-detail h2{font:1.7cqw/1.35 var(--serif);font-weight:500;margin:.35cqw 0 .2cqw}
  .model-hover-detail p{font:1.16cqw/1.65 var(--sans);color:#655a49;margin:0}
  @media(max-width:760px){.model-hover-detail{grid-column:1/-1;margin-top:10px;padding:10px 12px}.model-hover-detail h2{font-size:18px}.model-hover-detail p{font-size:13px}.model-hover-detail small{font-size:9px}}

/* Shared comparison framing: aligned engine scale and a separate caption band. */
.compare-title{top:12%}.compare-title h1{font-size:3.35cqw;line-height:1.3}
.compare-label{top:21.5%;width:45%;font-size:2.1cqw;text-align:center}
.compare-label.petrol{left:3%}.compare-label.diesel{left:52%}
.model-dock.split-petrol{inset:25.5% 52% 17% 3%}
.model-dock.split-diesel{inset:25.5% 3% 17% 52%}
.compare-caption{bottom:7%;width:45%;font-size:1.6cqw;line-height:1.5}
.compare-caption.petrol{left:3%}.compare-caption.diesel{left:52%}
.compare-axis{top:25%;bottom:18%}


/* The closing history sequence follows the teacher's spoken conclusion. */
.history-page{inset:15% 5% 7.5%}
.history-heading{width:49%;position:relative;z-index:1}
.history-chapter{display:block;font:1.2cqw/1.5 var(--sans);letter-spacing:.13em;color:#82684c;margin-bottom:.7cqw}
.history-page .year{font-size:5.5cqw;line-height:1.05;margin-bottom:1.4cqw;letter-spacing:-.025em}
.history-page h1{font-size:3.05cqw;line-height:1.45;max-width:51%;margin:0 0 1.5cqw;text-wrap:balance}
.history-page .history-copy{font-size:1.85cqw;line-height:1.8;max-width:48%;margin:0}
.history-page .history-takeaway{font-size:1.9cqw;line-height:1.65;max-width:48%;margin:1.6cqw 0 0;padding-top:1cqw}
.history-page .history-figure{width:41cqw;height:41cqw;right:-.7cqw;top:-1.3cqw;background-repeat:no-repeat;mix-blend-mode:multiply}
.history-tabs{padding-top:.65cqw;gap:.4cqw;align-items:center}
.history-tabs button{font-size:1.28cqw;padding:.65cqw .45cqw;white-space:nowrap;min-height:2.8cqw}
.history-tabs button.active{font-weight:600}
.history-intro{left:5.5%;top:17%;width:71%}
.history-intro h1{font-size:4.25cqw;line-height:1.4;letter-spacing:.015em;margin:0 0 1.5cqw}
.history-intro p{font-size:2.1cqw;line-height:1.65;max-width:78%}
.history-intro .eyebrow{margin-bottom:1.1cqw}
.history-panorama .art-layer{opacity:.90}
.history-panorama-navigation{pointer-events:none}
.history-panorama-navigation .history-tabs{pointer-events:auto;background:linear-gradient(0deg,#f4efe4e8,#f4efe4a0);border-color:#a88a605e}
.history-return{top:16%}
.history-return h1{font-size:4.05cqw}
.history-return p{font-size:2cqw}
.closing-scene .closing-copy{left:5.5%;top:19%;width:53%}
.closing-copy .eyebrow{font:1.2cqw/1.6 var(--sans);letter-spacing:.15em;color:var(--red);margin:0 0 1.3cqw}
.closing-copy h1{font-size:4.4cqw;line-height:1.42;margin:0 0 1.7cqw;letter-spacing:.015em}
.closing-copy h1>span{display:block}
.closing-copy p.tribute-line{font-size:1.95cqw;line-height:1.7;margin:.6cqw 0 0;max-width:100%;color:#5b4f3f}
.closing-copy p.tribute-line+ .tribute-line{margin-top:1cqw}
.closing-copy p.closing-message{font-size:2.05cqw;line-height:1.85;max-width:100%;color:#805536;border-top:1px solid #ab8a5e77;padding-top:1.2cqw;margin-top:1.4cqw}
.closing-future h1{min-height:12.5cqw}

/* Projection typography: content stays readable at the back of a classroom. */
.mechanism-copy{width:38%;top:17%;bottom:9%}
.mechanism-copy h1{font-size:3.55cqw;line-height:1.28;margin-bottom:1.35cqw}
.mechanism-copy .question{font-size:2.1cqw;line-height:1.55;margin:0 0 1cqw}
.mechanism-copy .conclusion{font-size:2cqw;line-height:1.55;margin:.75cqw 0;padding-top:.9cqw}
.mechanism-copy .energy-pair{font-size:2.25cqw;margin-top:1cqw}
.state-tags div{font-size:1.75cqw;line-height:1.35}
.state-tags strong{font-size:2.1cqw;line-height:1.35}
.motion-counts{gap:1cqw;padding-top:1cqw}
.motion-counts strong{font-size:3.4cqw}
.motion-counts span{font-size:1.55cqw;line-height:1.4}
.family-copy{top:21%;width:32.5%}
.family-copy h1{font-size:3.8cqw;line-height:1.25;margin-bottom:1.6cqw}
.family-copy .use{font-size:1.8cqw;line-height:1.5;letter-spacing:.02em;padding-top:1.15cqw;margin:0}
.family-copy .principle{font-size:2.15cqw;line-height:1.65;margin:1.5cqw 0;text-wrap:pretty}
.family-copy .family-energy{font-size:2.2cqw;line-height:1.5;white-space:nowrap;letter-spacing:.02em;padding-top:1.15cqw;margin-top:1.4cqw}
.family-tabs{gap:2.25cqw;padding-top:1cqw}
.family-tabs button{font-size:1.6cqw;line-height:1.5}
.heat-definition-heading span{font-size:1.55cqw}
.heat-types div{font-size:2.1cqw;line-height:1.45}
.heat-types small{font-size:1.45cqw}
.heat-common span{font-size:1.75cqw}
.heat-common p{font-size:2.55cqw}
.heat-definition-statement{font-size:2.1cqw;line-height:1.6}
.internal-page{inset:20% 6% 12%}
.internal-page h1{font-size:5.2cqw;line-height:1.25;letter-spacing:.04em;margin-bottom:2.5cqw}
.internal-page .internal-detail{font-size:2.65cqw;line-height:1.6;margin:0;max-width:90%;padding:1.4cqw 0 1.9cqw;border-bottom:1px solid #bfa47a88}
.internal-page .internal-types{display:flex;gap:2cqw;margin-top:2.6cqw;max-width:68%;font-size:3.2cqw}
.internal-types span{flex:1;padding:1.4cqw 2cqw;border-top:1px solid #bfa47a88;border-bottom:1px solid #bfa47a55;background:linear-gradient(125deg,#fffaf0b8,#e9dfca44);color:var(--ink)}
.parts-scene .mechanism-copy{width:43%;top:16%;bottom:8%}
.parts-scene .mechanism-copy h1{font-size:3.45cqw;margin-bottom:1.2cqw}
.parts-scene .parts-introduction-list{gap:.4cqw;padding-right:.5cqw;scrollbar-width:thin;pointer-events:auto}
.parts-scene .part-introduction{padding:.35cqw .65cqw;line-height:1.3;border-left:.18cqw solid #b65a3b}
.parts-scene .part-introduction strong{font-size:1.95cqw;line-height:1.3;font-weight:600}
.parts-scene .part-introduction p{font-size:1.8cqw;line-height:1.3;margin-left:.55cqw}
.model-hover-detail{margin-top:1.5cqw;padding:1.2cqw 1.4cqw}
.model-hover-detail small{font-size:1.4cqw;line-height:1.4}
.model-hover-detail h2{font-size:2.35cqw;line-height:1.4;margin:.5cqw 0}
.model-hover-detail p{font-size:1.95cqw;line-height:1.6}
.stage[data-scene="intake"] .mechanism-copy .state-tags,
.stage[data-scene="compression"] .mechanism-copy .state-tags,
.stage[data-scene="exhaust"] .mechanism-copy .state-tags{margin-top:1.5cqw;padding-top:1cqw;gap:1cqw 1.6cqw}
.stage[data-scene="intake"] .mechanism-copy .state-tags div,
.stage[data-scene="compression"] .mechanism-copy .state-tags div,
.stage[data-scene="exhaust"] .mechanism-copy .state-tags div{font-size:1.8cqw;line-height:1.35;gap:.35cqw}
.stage[data-scene="intake"] .mechanism-copy .state-tags strong,
.stage[data-scene="compression"] .mechanism-copy .state-tags strong,
.stage[data-scene="exhaust"] .mechanism-copy .state-tags strong{font-size:2.2cqw;line-height:1.35}
.stage[data-scene="intake"] .mechanism-copy .conclusion,
.stage[data-scene="compression"] .mechanism-copy .conclusion,
.stage[data-scene="exhaust"] .mechanism-copy .conclusion{font-size:2.05cqw;line-height:1.55;margin:1cqw 0;padding-top:1cqw}
.stage[data-scene="power"] .mechanism-copy{width:43%;top:16%;bottom:9%}
.stage[data-scene="power"] .model-dock{inset:14% 0 6% 47%}
.stage[data-scene="power"] .mechanism-copy h1{font-size:3.55cqw;line-height:1.25;margin-bottom:1.25cqw}
.stage[data-scene="power"] .cycle-findings{display:grid;gap:.65cqw;margin:0;color:#684d35}
.stage[data-scene="power"] .cycle-finding{font:1.95cqw/1.45 var(--sans);margin:0;padding-left:.75cqw;border-left:.18cqw solid #b65a3b;text-wrap:pretty}
.stage[data-scene="power"] .energy-chain{font-size:2.2cqw;line-height:1.35;gap:.6cqw;margin-top:1.1cqw}
.stage[data-scene="power"] .energy-chain i{font-size:2.4cqw}
.stage[data-scene="power"] .energy-chain span{padding:.4cqw .1cqw}
.stage[data-scene="power"] .mechanism-copy .state-tags{margin-top:1.1cqw;padding-top:.9cqw;gap:.8cqw 1.6cqw}
.stage[data-scene="power"] .mechanism-copy .state-tags div{font-size:1.8cqw;line-height:1.3;gap:.25cqw}
.stage[data-scene="power"] .mechanism-copy .state-tags strong{font-size:2.1cqw;line-height:1.3}
.stage[data-scene="stroke"] .mechanism-copy{width:43%}
.stage[data-scene="stroke"] .mechanism-copy .question{font-size:2.25cqw;line-height:1.6}
.stage[data-scene="stroke"] .mechanism-copy .conclusion{font-size:2.1cqw;line-height:1.65;white-space:pre-line}
.stage[data-scene="linkage"] .mechanism-copy{width:43%;top:16%;bottom:9%}
.stage[data-scene="linkage"] .model-dock{inset:14% 0 6% 47%}
.stage[data-scene="linkage"] .mechanism-copy h1{font-size:3.4cqw;line-height:1.27}
.stage[data-scene="linkage"] .mechanism-copy .question{font-size:2.2cqw;line-height:1.5;margin-bottom:.8cqw}
.stage[data-scene="linkage"] .cycle-findings{display:grid;gap:.7cqw;margin:.5cqw 0;color:#684d35}
.stage[data-scene="linkage"] .cycle-finding{font:1.9cqw/1.5 var(--sans);margin:0;padding-left:.7cqw;border-left:.18cqw solid #b65a3b;text-wrap:pretty}
.work-output{color:var(--red);font-weight:700;text-decoration:underline;text-decoration-thickness:.12cqw;text-underline-offset:.28cqw}
.task-page{inset:14% 5% 8%}
.task-page h1{font-size:3.5cqw;line-height:1.3;margin-bottom:1cqw}
.task-intro{font-size:2cqw;line-height:1.5;margin:.65cqw 0 1.35cqw}
.task-table{font-size:2cqw}
.task-table th,.task-table td{padding:1.05cqw .5cqw;line-height:1.45}
.task-table th{font-size:1.8cqw}
.task-table .row-title{font-size:2.15cqw}
.task-table th:first-child{width:14%}
.task-table th:last-child{width:32%}
.task-supplement{gap:1cqw;align-items:baseline;margin-top:1.35cqw;font-size:1.95cqw;line-height:1.45}
.task-supplement span:nth-child(3){margin-left:1.5cqw}
.calc-page{inset:13% 5% 7%}
.calc-page .calc-conditions{font-size:2cqw;line-height:1.5;max-width:100%;margin:.8cqw 0 1.2cqw}
.task-page.calc-page .tach-grid{height:auto;min-height:0;grid-template-columns:25% 1fr;gap:3%;align-items:center}
.calc-page .tach-grid img{width:100%;transform:scale(1.07)}
.calc-page .problem-lines{gap:.55cqw;font-size:2cqw;line-height:1.4;align-content:start}
.calc-page .calc-question{font-size:2cqw;line-height:1.4;margin:0!important;text-wrap:pretty}
.calc-page .formula{font-size:2cqw;line-height:1.4;padding-top:.45cqw}

/* A quiet full-page timer lets the teacher give students thinking time. */
.countdown-page{position:absolute;inset:13% 6% 7%;display:flex;flex-direction:column;align-items:center;text-align:center}
.countdown-page header{margin-bottom:.6cqw}
.countdown-kicker{font-size:1.55cqw;line-height:1.4;letter-spacing:.15em;color:#8c6d4b;margin:0 0 .5cqw}
.countdown-page h1{font:3.7cqw/1.3 var(--serif);font-weight:500;margin:0;color:var(--ink)}
.countdown-prompt{font:2.15cqw/1.55 var(--serif);color:#766046;margin:.5cqw 0 .6cqw}
.countdown-clock{display:flex;flex-direction:column;align-items:center;min-width:0}
.countdown-ring{--timer-progress:360deg;width:24cqw;aspect-ratio:1;border-radius:50%;padding:.42cqw;background:conic-gradient(from 0deg,#aa593a var(--timer-progress),#d4c5ac var(--timer-progress));box-shadow:0 1.1cqw 3cqw #6c4d2610;position:relative}
.countdown-ring:before{content:"";position:absolute;inset:-.65cqw;border:1px solid #b79b702f;border-radius:50%;pointer-events:none}
.countdown-ring>div{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:.8cqw;width:100%;height:100%;border-radius:50%;background:radial-gradient(circle at 50% 40%,#fffcf4,#f4efe4 72%)}
.countdown-label{font-size:1.6cqw;line-height:1.5;letter-spacing:.12em;color:#8b7455}
.countdown-ring output{font:6.7cqw/1.1 Georgia,var(--sans);font-variant-numeric:tabular-nums;letter-spacing:.01em;color:var(--red)}
.countdown-ring.finished{background:#a35034}
.countdown-ring.finished output{color:#954228}
#countdown-status{font-size:1.85cqw;line-height:1.5;color:#796044;margin:1.1cqw 0 .75cqw;min-height:2.8cqw}
.countdown-actions{display:flex;gap:.9cqw}
.countdown-actions button{border:1px solid #b3946c7a;background:#faf5e9b8;color:#806342;font-size:1.55cqw;line-height:1.4;padding:.55cqw 1.2cqw;min-width:6.8cqw}
.countdown-actions button:hover{color:var(--red);border-color:var(--red);background:#f9efdc}
.countdown-calculation{display:grid;grid-template-columns:60% 1fr;grid-template-rows:auto 1fr;column-gap:5%;align-items:start;text-align:left}
.countdown-calculation header{grid-column:1/-1;margin:0 0 2cqw}
.countdown-calculation h1{font-size:3.5cqw}
.countdown-assignment{padding-top:.4cqw}
.countdown-conditions{font-size:2.1cqw;line-height:1.65;color:#5c4e3e;margin:0;padding-bottom:1.4cqw;border-bottom:1px solid #bfa47a88}
.countdown-conditions b{font-weight:600;color:var(--red);white-space:nowrap}
.countdown-assignment ol{font:2.15cqw/1.65 var(--serif);padding-left:2.5cqw;margin:1.5cqw 0 0}
.countdown-assignment li{padding-left:.4cqw;margin-bottom:1.05cqw}
.countdown-assignment li::marker{color:var(--red)}
.countdown-calculation .countdown-clock{align-self:center;text-align:center;padding-bottom:2cqw}
.countdown-calculation .countdown-ring{width:24.5cqw}
.countdown-calculation .countdown-ring output{font-size:6.4cqw}
.countdown-calculation #countdown-status{font-size:1.7cqw}
.quantity{white-space:nowrap}

/* The new self-contained dual-engine demonstration replaces the old split models. */
.comparison-dock{inset:12% 2% 10%;z-index:4}
.comparison-scene .controls{opacity:1;transform:none;pointer-events:auto}