@import url('https://fonts.googleapis.com/css2?family=DM+Sans:wght@400;500;600;700&family=Manrope:wght@400;500;600;700;800&display=swap');
:root{--ink:#163732;--text:#39504c;--muted:#687a74;--orange:#e76d44;--green:#16756c;--line:#d8dfd8;--paper:#f8f8f2;--pale:#e8efea}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:100px}body{margin:0;background:var(--paper);color:var(--ink);font-family:'DM Sans',Arial,sans-serif;line-height:1.65}h1,h2,h3,.brand{font-family:Manrope,Arial,sans-serif}h1,h2,h3,p{margin-top:0}h1{font-size:clamp(48px,5.5vw,80px);line-height:1.09;letter-spacing:-4px;margin:24px 0}h1 em{font-style:normal;color:var(--orange)}h2{font-size:clamp(30px,3.4vw,46px);line-height:1.2;letter-spacing:-1.8px}h3{font-size:23px;line-height:1.4;letter-spacing:-.6px}a{color:inherit}button,input,select{font:inherit}button{cursor:pointer}button:focus-visible,a:focus-visible,input:focus-visible,summary:focus-visible,select:focus-visible{outline:3px solid var(--orange);outline-offset:4px}header{position:sticky;top:0;z-index:10;display:flex;align-items:center;justify-content:space-between;padding:20px 5%;border-bottom:1px solid var(--line);background:#f8f8f2f5;backdrop-filter:blur(12px)}.brand{font-weight:800;text-decoration:none;font-size:30px;letter-spacing:-1.8px}.brand span{color:var(--orange)}.brand small{font-size:9px;letter-spacing:1.5px;margin-left:15px;vertical-align:middle}nav{display:flex;align-items:center;gap:27px}nav a{text-decoration:none;font-size:13px;font-weight:600}nav a:hover{color:var(--orange)}.nav-cta{border:1px solid var(--ink);border-radius:5px;padding:9px 15px}main>section{padding:90px 6%;max-width:1500px;margin:auto;scroll-margin-top:10px}.hero{display:grid;grid-template-columns:1fr 1fr;gap:7%;padding-top:65px;padding-bottom:60px;align-items:center}.eyebrow,.label{font-size:10px;letter-spacing:1.6px;font-weight:700}.eyebrow{margin-bottom:20px}.dot{display:inline-block;width:7px;height:7px;background:var(--orange);border-radius:50%;margin-right:8px}.lead{font-size:17px;max-width:480px;color:var(--text);line-height:1.8}.actions{display:flex;gap:24px;align-items:center;flex-wrap:wrap;margin:30px 0 45px}.button{background:var(--ink);border:1px solid var(--ink);color:white;border-radius:5px;padding:13px 21px;display:inline-flex;gap:25px;align-items:center;text-decoration:none;font-size:13px;font-weight:600}.button:hover{background:var(--green)}.text-link{font-size:13px;font-weight:600;text-underline-offset:5px}.hero-meta{display:flex;gap:25px;font-size:10px;color:var(--muted);letter-spacing:.7px}.hero-art{background:#e6eeea;border:1px solid #d3dfd8;border-radius:12px;padding:26px;box-shadow:0 18px 35px #25423608;transform:rotate(-1deg)}.art-top{display:flex;justify-content:space-between;font-size:9px;letter-spacing:1px;color:#607e71;margin-bottom:25px}.hero-art h2{font-size:27px;letter-spacing:-.7px;line-height:1.3;margin-bottom:10px}.hero-art svg{width:100%;height:auto}.art-note{font-size:9px;color:var(--muted);margin-top:-7px}.scale-row{display:flex;justify-content:space-between;align-items:center;font-family:monospace;margin:10px 0}.scale-row span{font-size:18px;width:45px;text-align:center}.scale-row i{font-size:11px;font-style:normal;color:#748e80}.scale-row.accent{color:var(--orange)}.hero-art>a{font-size:11px;display:block;text-align:right;margin-top:20px}.chapter-strip{display:flex;justify-content:space-between;gap:20px;flex-wrap:wrap;border-block:1px solid var(--line);padding:22px 6%;font-size:12px}.chapter-strip span:first-child{font-size:9px;letter-spacing:1px;color:var(--muted)}.section-heading{display:grid;grid-template-columns:1.3fr 1fr;column-gap:10%;margin-bottom:38px}.section-heading .eyebrow{grid-column:1/-1;color:var(--green)}.section-heading h2{margin:0}.section-heading>p:last-child{align-self:end;color:var(--muted);margin:0;max-width:480px}.definition{display:grid;grid-template-columns:2fr 1fr;background:var(--ink);color:white;border-radius:9px;padding:35px;gap:45px}.definition p{color:#d3dfd9;margin-bottom:0}.definition .label{color:#9bbab0}.definition aside{border-left:1px solid #4c6960;padding-left:32px;font-size:14px}.definition small{line-height:1.9;color:#b7cdc3}.formula{font-family:Georgia,'Times New Roman',serif;font-size:21px;line-height:1.8;overflow-wrap:anywhere}.formula.big{font-size:clamp(25px,3vw,39px);margin:14px 0}.formula.big span{color:#80aca0;margin:0 16px}sub,sup{line-height:0;font-size:.65em}.three{display:grid;grid-template-columns:repeat(3,1fr);gap:22px}.examples{margin:25px 0 40px}.examples article{border-bottom:1px solid var(--line);padding:20px 0}.examples span{font-size:9px;letter-spacing:1px;color:var(--muted)}.examples h3{font-family:Georgia,serif;font-size:29px;margin:10px 0}.examples p{font-size:14px;color:var(--text)}.two{display:grid;grid-template-columns:1fr 1fr;gap:24px;margin-top:26px}.panel{border:1px solid var(--line);border-radius:8px;padding:30px;background:#ffffff70}.panel p,.panel li{font-size:14px;color:var(--text)}.panel p:last-child{margin-bottom:0}.panel .formula{color:var(--ink);font-size:21px}.subheading{margin-top:45px}.table-wrap{overflow:auto;border:1px solid var(--line);border-radius:8px}table{width:100%;border-collapse:collapse;font-size:14px;min-width:650px}th{text-align:left;background:var(--pale);font-size:11px;text-transform:uppercase;letter-spacing:1px;padding:15px 20px}td{padding:17px 20px;border-top:1px solid var(--line)}td:nth-child(2){font-family:Georgia,serif;font-size:18px}details{border-top:1px solid var(--line);margin-top:20px;padding:15px 0}summary{cursor:pointer;font-size:14px;font-weight:600}details p{margin:14px 0 0}.warning{background:#faeee3;border-left:3px solid var(--orange);padding:22px 28px;margin-top:22px;border-radius:0 6px 6px 0}.warning p{font-size:14px;margin-bottom:8px}.lab-section{background:#eef2ed;max-width:none!important;border-block:1px solid var(--line)}.lab-shell{border:1px solid #cbd8cf;border-radius:10px;background:var(--paper);overflow:hidden}.tabs{display:flex;border-bottom:1px solid var(--line);background:#e2eae3}.tabs button{flex:1;border:none;background:none;padding:18px 10px;color:var(--muted);font-size:13px;border-bottom:3px solid transparent}.tabs button[aria-selected=true]{border-bottom-color:var(--orange);background:var(--paper);color:var(--ink);font-weight:700}.lab-body{display:grid;grid-template-columns:1fr 1.1fr;gap:40px;padding:35px}.lab-body h3{font-size:26px}.lab-controls{display:flex;gap:25px;margin:22px 0}.lab-controls label{flex:1}.lab-body p{font-size:14px;color:var(--text)}label{display:block;font-size:12px;font-weight:600}output{float:right;color:var(--green);font-variant-numeric:tabular-nums}input[type=range]{display:block;width:100%;accent-color:var(--green);margin:18px 0;cursor:pointer}select{margin-top:10px;padding:9px 12px;background:var(--paper);border:1px solid #b8c9bd;border-radius:5px;max-width:100%;color:var(--ink)}.play-controls{display:flex;gap:8px;margin-top:25px;align-items:center}.secondary,.icon-button{border:1px solid #bac9bf;border-radius:5px;background:transparent;padding:12px 16px;font-size:12px;color:var(--ink)}.secondary:hover,.icon-button:hover{background:var(--pale)}.icon-button{font-size:18px;padding:6px 12px}.animation{background:#e5eee8;border-radius:7px;padding:25px;min-height:350px;display:flex;flex-direction:column;justify-content:space-between}.animation .label{color:var(--green)}#anim-stage{display:flex;flex-direction:column;gap:12px;justify-content:center;min-height:200px}.math-stage{font-family:Georgia,serif;text-align:center;font-size:clamp(24px,2.4vw,35px);animation:appear .5s ease both}.math-stage.secondary-line{font-size:20px;color:var(--green)}.math-stage b{color:var(--orange);font-weight:normal}.exponent-track{display:flex;gap:5px;justify-content:center;min-height:38px;align-items:center;flex-wrap:wrap}.exponent-track span{background:var(--green);color:white;border-radius:3px;min-width:24px;padding:4px;text-align:center;font-size:12px;animation:appear .4s both}.exponent-track span.other{background:var(--orange)}.step-dots{display:flex;justify-content:center;gap:7px}.step-dots span{width:7px;height:7px;background:#bbcec1;border-radius:50%}.step-dots span.active{background:var(--orange)}#step-caption{min-height:44px;margin:12px 0 0;font-size:12px;text-align:center}.badge{display:inline-block;color:var(--green);font-size:9px;font-weight:700;letter-spacing:1px;margin-bottom:18px}.graph-panel svg,.scale-panel svg{width:100%;height:auto;margin-top:12px}ol{padding-left:18px}li{margin-bottom:8px}.engineering-grid{display:grid;grid-template-columns:1.2fr 1fr;gap:24px}.engineering-grid .feature{grid-row:span 2}.number{font-family:Georgia,serif;font-size:40px;color:#9ab7a8;display:block;margin-bottom:16px}.physics-section{background:#e8eee9;max-width:none!important}.meter{height:14px;background:#cadbd1;border-radius:4px;overflow:hidden;margin:22px 0}.meter span{display:block;background:var(--orange);height:100%;transition:width .3s}.nuclei{display:grid;grid-template-columns:repeat(16,1fr);gap:5px;margin:20px 0}.nuclei span{aspect-ratio:1;border-radius:50%;background:var(--green);transition:opacity .4s}.cooling{display:grid;grid-template-columns:1fr 1fr;gap:45px;margin-top:24px}.cooling>div:last-child{align-self:center}.muted{color:var(--muted)!important}.small{font-size:12px}.exercise-toolbar{display:flex;justify-content:space-between;align-items:center;gap:20px;flex-wrap:wrap;margin-bottom:20px}.filter-buttons{display:flex;gap:6px;flex-wrap:wrap}.filter-buttons button{padding:8px 13px;border:1px solid var(--line);background:none;border-radius:30px;color:var(--ink);font-size:12px}.filter-buttons button.active{background:var(--ink);color:white}#score{font-size:12px;color:var(--green)}#exercises{display:grid;grid-template-columns:1fr 1fr;gap:20px;margin-bottom:25px}.exercise{padding:26px;border:1px solid var(--line);background:#fff9;border-radius:8px}.exercise h3{font-size:18px;margin-bottom:12px}.exercise .badge{margin-bottom:10px}.exercise p{font-size:14px}.answer-row{display:flex;gap:8px;align-items:center}.answer-row input,.answer-row select{width:100%;min-width:0;padding:12px;background:white;border:1px solid #becdc1;border-radius:5px;color:var(--ink);margin:0}.answer-row button{white-space:nowrap;padding:13px 16px;gap:0}.feedback{margin-top:15px;font-size:13px}.feedback:empty{display:none}.feedback.correct{color:#126249}.feedback.incorrect{color:#a74b2d}.solution{font-size:13px!important}.exercise .solution-button{border:0;background:none;text-decoration:underline;text-underline-offset:3px;padding:13px 0 0;font-size:12px;color:var(--muted)}.sources{border-top:1px solid var(--line);padding-block:55px!important}.sources h2{font-size:30px}.sources>p:not(.eyebrow){max-width:800px;font-size:14px;color:var(--muted)}.source-links{display:grid;grid-template-columns:repeat(3,1fr);gap:12px}.source-links a{font-size:12px;text-decoration:none;border-bottom:1px solid var(--line);padding:12px 0}.source-links a:hover{color:var(--orange)}footer{border-top:1px solid var(--line);padding:25px 6%;display:flex;gap:25px;align-items:center;justify-content:space-between}footer p,footer small{font-size:11px;color:var(--muted);margin:0}@keyframes appear{from{opacity:0;transform:translateY(10px)}to{opacity:1;transform:none}}@media(min-width:1550px){.lab-section,.physics-section{padding-inline:max(6%,calc((100vw - 1320px)/2))}}@media(max-width:1000px){.brand small{display:none}nav{gap:18px}.hero{gap:30px}h1{letter-spacing:-2px}.hero-meta{gap:12px;font-size:9px}.lab-body{gap:20px;padding:25px}.play-controls{flex-wrap:wrap}.source-links{grid-template-columns:1fr 1fr}.hero-art{padding:20px}.art-top{font-size:8px}}@media(max-width:760px){header{position:relative;display:block;padding:16px 6%}nav{margin-top:12px;gap:16px;overflow:auto}nav a{font-size:11px;white-space:nowrap}.nav-cta{padding:5px 9px}.hero{grid-template-columns:1fr;padding-top:35px}.hero h1{font-size:58px}.hero-art{transform:none}.hero-meta{font-size:10px;gap:22px}.chapter-strip{font-size:11px}.chapter-strip span:first-child{width:100%}main>section{padding:55px 6%}.section-heading{grid-template-columns:1fr;gap:20px}.two,.three,.definition,.lab-body,.engineering-grid,.cooling,#exercises{grid-template-columns:1fr}.definition{padding:25px;gap:25px}.definition aside{border-left:0;border-top:1px solid #4c6960;padding:20px 0 0}.examples{gap:0}.examples article{padding:18px 0}.panel{padding:23px}.lab-body{padding:20px}.tabs button{font-size:11px;padding:14px 5px}.animation{min-height:310px}.source-links{grid-template-columns:1fr}footer{flex-wrap:wrap;gap:12px}footer small{width:100%}.hero-art h2{font-size:25px}.formula{font-size:20px}html{scroll-padding-top:20px}}@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{animation:none!important;transition:none!important}}

[hidden]{display:none!important}

.animation .tile-explanation{font-size:12px;line-height:1.7;text-align:left;color:var(--text);border-top:1px solid #c3d4c8;padding-top:14px;margin:12px 0 20px}.example-controls{display:flex;justify-content:flex-end;margin-top:10px}.example-controls .secondary{background:var(--paper)}
.concept-link{color:var(--green);text-decoration:underline;text-decoration-style:dotted;text-underline-offset:4px;text-decoration-thickness:1px}.concept-link:hover{text-decoration-style:solid;color:var(--orange)}.experiment{border-top:1px solid var(--line);margin-top:26px;padding-top:25px}.experiment .eyebrow{color:var(--green);font-size:9px;margin-bottom:20px}.experiment h4{font-family:Manrope,Arial,sans-serif;font-size:16px;line-height:1.4;margin:22px 0 10px}.experiment h4:first-of-type{margin-top:0}.experiment .experiment-note{font-size:11px;color:var(--muted);padding-left:12px;border-left:2px solid #a4bca9;margin-top:20px}.experiment-table{min-width:0;font-size:12px;table-layout:fixed}.experiment-table caption{font-size:10px;text-align:left;padding:12px 14px;background:#e3ebe1;color:var(--text)}.experiment-table td,.experiment-table th{padding:12px 10px;overflow-wrap:anywhere}.experiment-table th{font-size:9px;letter-spacing:.4px}.experiment-table td:nth-child(2){font-family:inherit;font-size:12px}.cooling-experiment{grid-column:1/-1;margin-top:0}.cooling-experiment .two{margin-top:0}.mission-art{margin:0;border-bottom:1px solid #34554a;background:#102e29;position:relative}.mission-art img{display:block;width:100%;height:clamp(190px,26vw,330px);object-fit:cover;object-position:center}.mission-art figcaption{padding:12px 30px;color:#b9cfbf;font-size:11px;border-top:1px solid #34554a;background:#16372d}

.mission-art img{height:auto;aspect-ratio:3/1;object-fit:contain}
