:root{color-scheme:dark;--bg:#101c20;--panel:#132125;--line:#2c3b3e;--text:#f2f1e9;--muted:#93a4a6;--accent:#d9ee98;--intake:#76c8dd;--compression:#c7a7e7;--power:#ffae67;--exhaust:#91a2b4}
.exhaust-row{display:flex;align-items:center;justify-content:space-between;gap:12px;margin-top:12px;font-size:7px;letter-spacing:1px;color:var(--muted)}.exhaust-row select{font-size:10px;color:var(--accent);background:#1b2d30;border:1px solid #43564b;border-radius:3px;padding:5px 7px;min-width:115px;cursor:pointer}
.sound-control{position:absolute;left:0;top:219px;z-index:3;width:221px;padding:11px 12px 9px;background:#142226e8;border:1px solid var(--line);border-radius:5px}.sound-control button{display:flex;gap:10px;align-items:center;width:100%;background:transparent;padding:0;color:var(--muted)}.sound-control button.active{color:var(--accent)}.sound-control button:disabled{opacity:.5;cursor:wait}.sound-control button svg{width:17px;height:17px;flex-shrink:0}.sound-control svg [hidden]{display:none}.sound-control button span{display:flex;align-items:center;justify-content:space-between;width:100%;font-size:8px;letter-spacing:1px}.sound-control strong{font-size:8px;font-weight:400}.sound-volume{display:flex;align-items:center;gap:11px;margin-top:13px}.sound-volume label{font-size:7px;letter-spacing:1px;color:var(--muted)}.sound-volume input{flex:1;min-width:0}.sound-volume output{font-size:8px;color:#b6c5c4;min-width:25px;text-align:right;font-variant-numeric:tabular-nums}.sound-control small{display:block;font-size:8px;color:#7f999e;margin-top:10px;letter-spacing:.15px}
@media(max-width:760px){.sound-control{top:234px;width:221px;padding:9px 12px}.sound-volume{margin-top:11px}.sound-control small{margin-top:8px}}
*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--text);font-family:Arial,Helvetica,sans-serif;font-size:13px}button,input,select{font:inherit}button,a,input,select{-webkit-tap-highlight-color:transparent}button{cursor:pointer;color:inherit}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible{outline:2px solid var(--accent);outline-offset:5px}button{border:0}a{color:inherit}button svg{width:22px;height:22px;fill:none;stroke:currentColor;stroke-width:1.4;stroke-linejoin:round;stroke-linecap:round}button svg[hidden]{display:none}.masthead{height:88px;margin:0 38px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line)}.wordmark{display:flex;align-items:center;gap:13px;text-decoration:none;font-size:11px;font-weight:700;line-height:1.45;letter-spacing:2.1px}.wordmark svg{width:38px;stroke:var(--accent);fill:none;stroke-width:1.3}.masthead-caption{font-size:9px;letter-spacing:2.3px;color:var(--muted);padding-right:80px}.text-button{background:transparent;font-size:11px;color:#c6cfcb;padding:12px 0 12px 16px}.text-button span{color:var(--accent);margin-left:14px;font-size:18px}main{display:grid;grid-template-columns:minmax(0,1fr) 326px;min-height:620px;height:calc(100dvh - 226px);margin:0 38px}.stage{position:relative;overflow:hidden;min-width:0}.heading{position:absolute;top:31px;left:0;z-index:2;pointer-events:none}.eyebrow{font-size:9px;letter-spacing:2px;display:flex;align-items:center;gap:12px;color:#b9c5bb}.tiny-line{height:1px;width:24px;background:var(--accent)}.muted{color:#64767b}h1{margin:17px 0 9px;font-size:clamp(28px,3.1vw,48px);font-weight:400;letter-spacing:-1.6px;line-height:1.1}h1 em{font-family:Georgia,'Times New Roman',serif;font-weight:400;color:var(--accent)}.heading p{font-size:12px;color:var(--muted);letter-spacing:.25px;margin:0}#viewport{position:absolute;inset:126px 0 0}#viewport canvas{display:block;width:100%;height:100%;outline:none;touch-action:none}.view-bar{position:absolute;top:166px;left:0;display:flex;padding:4px;background:#142226e8;border:1px solid var(--line);border-radius:5px;z-index:3}.view-bar button{padding:8px 14px;background:transparent;color:#a5b3b5;border-radius:3px;font-size:11px;transition:.2s}.view-bar button.active{background:#d9ee98;color:#16251f}.model-stamp{position:absolute;top:177px;right:26px;display:flex;gap:8px;align-items:center;font-size:8px;letter-spacing:1.6px;color:#99aeb0}.status-dot{background:var(--accent);width:5px;height:5px;border-radius:100%;box-shadow:0 0 10px #d9ee9830}.camera-tools{position:absolute;right:20px;bottom:88px;display:flex;flex-direction:column;gap:7px}.camera-tools button{background:#152429d9;border:1px solid #314449;border-radius:5px;width:36px;height:36px;display:grid;place-items:center;color:#b2c0c0}.camera-tools button:hover,.camera-tools button.active{color:var(--accent);border-color:#718965}.camera-tools svg{width:18px;height:18px}.viewer-caption{position:absolute;bottom:27px;left:0;font-size:8px;letter-spacing:1.5px;color:#859ca1;display:flex;align-items:center;gap:11px;pointer-events:none}.viewer-caption>span{font-size:23px;color:#b6c6c4}.viewer-caption i{font-style:normal;color:#526b70}.orientation{position:absolute;bottom:19px;right:26px;width:55px;height:57px;font-size:8px;color:#91a7a9}.orientation svg{stroke:#698789;stroke-width:1;fill:none;width:54px;height:48px;position:absolute;bottom:0}.orientation span{position:absolute;left:24px;top:-1px}.orientation small{position:absolute;bottom:0;left:0;font-size:8px}.orientation small:last-child{left:auto;right:0}aside{border-left:1px solid var(--line);padding:31px 0 15px 28px;overflow:auto;scrollbar-width:thin;scrollbar-color:#334e50 transparent}aside section{padding-bottom:21px;border-bottom:1px solid var(--line);margin-bottom:23px}aside section:last-child{border-bottom:0;margin:0}.section-kicker{font-size:9px;letter-spacing:1.55px;color:#aebdbd;display:flex;justify-content:space-between}.section-kicker>span{font-size:8px;color:#627c81;letter-spacing:1px}.engine-title{display:flex;align-items:center;justify-content:space-between;margin:18px 0 12px;gap:9px}h2{font-size:29px;font-weight:400;letter-spacing:-.8px;margin:0}.pill{font-size:6.5px;letter-spacing:.7px;padding:6px;border:1px solid #4a5a46;border-radius:3px;color:var(--accent);white-space:nowrap}.description{font-size:11px;line-height:1.7;color:var(--muted);margin:0 0 21px;max-width:260px}.spec-grid{display:grid;grid-template-columns:1fr 1fr;gap:22px 16px}.spec-grid>div{display:flex;flex-direction:column;gap:7px}.spec-grid strong{font-size:29px;font-weight:400;letter-spacing:-1px}.spec-grid small{font-size:12px;letter-spacing:0;color:#bac6c6}.spec-grid span{font-size:7px;letter-spacing:1px;color:var(--muted)}.bore-stroke{display:flex;align-items:center;justify-content:space-between;margin-top:24px}.bore-stroke span{font-size:8px;letter-spacing:1px;color:var(--muted)}.bore-stroke strong{font-size:11px;font-weight:400}.bore-stroke small{color:var(--muted)}.layers-card .section-kicker{margin-bottom:15px}.toggle-row{display:flex;align-items:center;height:32px;position:relative;cursor:pointer;font-size:11px}.toggle-row>span:first-child{display:flex;align-items:center;gap:10px}.layer-dot{display:inline-block;width:7px;height:7px;border-radius:2px}.aluminum{background:#afbab9}.charcoal{background:#577070}.brass{background:#bca379}.mint{background:var(--accent)}.toggle-row input{position:absolute;right:0;opacity:0;width:32px;height:20px;cursor:pointer}.switch{margin-left:auto;width:26px;height:14px;border:1px solid #465b5c;border-radius:20px;background:#223439;position:relative;pointer-events:none}.switch:after{content:'';position:absolute;left:3px;top:3px;width:6px;height:6px;background:#8c9d9f;border-radius:50%;transition:transform .2s}.toggle-row input:checked+.switch{background:var(--accent);border-color:var(--accent)}.toggle-row input:checked+.switch:after{background:#283823;transform:translateX(12px)}.toggle-row input:focus-visible+.switch{outline:2px solid var(--accent);outline-offset:4px}.cylinder-title{display:flex;justify-content:space-between;align-items:center;margin:20px 0 17px}h3{font-size:18px;font-weight:400;letter-spacing:-.3px;margin:0}.cylinder-title>span{font-size:8px;letter-spacing:1.4px;color:var(--power);padding:5px 7px;border:1px solid currentColor;border-radius:3px}.cycle-track{display:grid;grid-template-columns:repeat(4,1fr);gap:5px}.cycle-track>div{font-size:8px;color:#8e9da1;display:flex;flex-direction:column;gap:7px}.cycle-track>div>span{height:3px;border-radius:2px;background:#304349;transition:background .2s}.cycle-track [data-stroke=intake].active>span{background:var(--intake)}.cycle-track [data-stroke=compression].active>span{background:var(--compression)}.cycle-track [data-stroke=power].active>span{background:var(--power)}.cycle-track [data-stroke=exhaust].active>span{background:var(--exhaust)}.cycle-track>div.active{color:#e2e7e2}#stroke-description{font-size:10px;line-height:1.7;min-height:34px;color:#9cacaf;margin:15px 0 12px}.valve-state{display:flex;justify-content:space-between;font-size:8px;color:#738f94;letter-spacing:1px}.valve-state i{font-style:normal;color:#c0cccb;margin-left:4px;font-size:7px}.valve-state i.open{color:var(--accent)}#angle-readout{font-variant-numeric:tabular-nums}.firing-label{margin-top:23px;display:flex;justify-content:space-between;font-size:8px;letter-spacing:1px}.firing-label>span{font-size:6px;color:#718a8f;letter-spacing:.6px}.firing-order{display:flex;justify-content:space-between;align-items:center;margin-top:12px}.firing-order button{background:#1c2d32;border:1px solid #3a5055;width:29px;height:29px;border-radius:4px;color:#c5d0cc;font-size:11px;transition:background .15s}.firing-order button.selected{border-color:var(--accent);color:var(--accent)}.firing-order button.firing{background:#e4bb78;color:#172320;border-color:#e4bb78}.firing-order>span{font-size:9px;color:#5a7378}.transport{margin:0 38px;min-height:138px;display:grid;grid-template-columns:235px minmax(170px,1fr) 183px minmax(160px,1fr);gap:38px;align-items:center;border-top:1px solid var(--line)}.playback{display:flex;gap:13px;align-items:center}.playback #play{border-radius:50%;background:var(--accent);color:#1a291f;width:46px;height:46px;display:grid;place-items:center;flex-shrink:0}#play svg{stroke-width:2.6}#play-icon{fill:currentColor;stroke:none;width:18px}.playback>div{display:flex;flex-direction:column;gap:6px}.playback>div>span{font-size:8px;letter-spacing:1.1px;white-space:nowrap}.playback small{font-size:9px;color:#80989d}.playback #step{margin-left:3px;background:transparent;color:#9cb0b2;padding:5px}.playback #step svg{width:17px}.rpm-control>div:first-child{display:flex;justify-content:space-between;align-items:center;margin-bottom:13px}.transport label{font-size:8px;letter-spacing:1.3px;color:#9fb1b3}.rpm-control output{font-size:23px;font-weight:400;letter-spacing:-.6px;font-variant-numeric:tabular-nums}.rpm-control output small{font-size:9px;color:#8fa5a9;letter-spacing:.5px}input[type=range]{appearance:none;width:100%;height:3px;background:#3a4b4d;accent-color:var(--accent);display:block;margin:0;cursor:pointer;border-radius:3px}input[type=range]::-webkit-slider-thumb{appearance:none;width:10px;height:10px;border-radius:50%;background:var(--accent);border:2px solid #d9ee98;box-shadow:0 0 0 4px #d9ee9810}input[type=range]::-moz-range-thumb{width:8px;height:8px;border-radius:50%;background:var(--accent);border:0}.range-labels{display:flex;justify-content:space-between;margin-top:10px;color:#6f8b90;font-size:8px;letter-spacing:.5px}.speed-control{border-left:1px solid var(--line);padding-left:28px}.speed-control label{display:block;margin-bottom:11px}.speed-control select{background:#1a2c30;border:1px solid #3e5255;border-radius:4px;color:#d0d8cc;padding:9px 8px;font-size:10px;width:100%;cursor:pointer}.phase-control label{display:flex;justify-content:space-between;margin-bottom:19px}.phase-control output{font-size:8px;letter-spacing:0;color:#bed0c9;font-variant-numeric:tabular-nums}#labels{position:absolute;inset:126px 0 0;pointer-events:none;overflow:hidden}.cyl-label{position:absolute;border:1px solid #799487;background:#122125df;color:#c8d5cd;font:10px Arial;border-radius:50%;width:23px;height:23px;display:grid;place-items:center;transform:translate(-50%,-50%);transition:color .2s,background .2s;pointer-events:auto;cursor:pointer}.cyl-label.selected{background:var(--accent);color:#1c3026;border-color:var(--accent);box-shadow:0 0 0 4px #d9ee9810}.cyl-label.firing:not(.selected){border-color:#e4bb78;color:#e4bb78}#loading{position:absolute;inset:210px 0 0;display:flex;align-items:center;justify-content:center;gap:13px;background:var(--bg);z-index:5;font-size:12px;color:var(--muted)}#loading.hidden{display:none}.loader{width:20px;height:20px;border:1px solid #4b656a;border-top-color:var(--accent);border-radius:50%;animation:spin 1s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}dialog{background:#16282d;color:var(--text);border:1px solid #455d60;border-radius:10px;max-width:610px;padding:42px;box-shadow:0 20px 120px #0008}dialog::backdrop{background:#071014c9;backdrop-filter:blur(6px)}dialog h2{font-family:Georgia,serif;font-size:36px;margin:23px 0}dialog p{font-size:13px;line-height:1.8;color:#b8c7c8}#close-about{position:absolute;top:15px;right:20px;background:none;font-size:26px;color:#a6bcbe}.source-links{display:flex;gap:25px;margin-top:24px}.source-links a{color:var(--accent);font-size:11px}.shortcut-note{padding-top:20px;border-top:1px solid var(--line);font-size:10px!important}#toast{position:fixed;bottom:150px;left:50%;transform:translate(-50%,10px);background:var(--accent);color:#1a2b23;padding:11px 19px;border-radius:6px;font-size:12px;opacity:0;transition:.2s;pointer-events:none;z-index:10}#toast.show{opacity:1;transform:translate(-50%,0)}
aside section{margin-bottom:18px;padding-bottom:18px}.description{margin-bottom:17px}.spec-grid{gap:17px 16px}.bore-stroke{margin-top:19px}.toggle-row{height:30px}.firing-label{margin-top:17px}.cylinder-title{margin-top:17px}#stroke-description{margin-top:12px;margin-bottom:10px}
@media(min-width:1600px){main{grid-template-columns:minmax(0,1fr) 350px}.heading{top:39px}h1{font-size:52px}aside{padding-top:39px}.engine-title{margin-top:24px}.description{font-size:12px}.spec-grid{gap:22px}.spec-grid strong{font-size:32px}.toggle-row{height:32px}.transport{gap:55px;grid-template-columns:260px 1fr 200px 1fr}.cycle-card{padding-top:5px}.section-kicker{font-size:10px}}
@media(max-height:850px) and (min-width:1000px){main{min-height:630px;height:calc(100dvh - 190px)}.masthead{height:72px}.transport{min-height:118px}aside{padding-top:25px}aside section{margin-bottom:18px;padding-bottom:18px}.spec-grid{gap:17px}.description{margin-bottom:16px}.engine-title{margin-top:14px}.bore-stroke{margin-top:19px}.toggle-row{height:29px}.cylinder-title{margin-top:16px}.firing-label{margin-top:18px}}
@media(max-width:1100px){.masthead,main,.transport{margin-left:24px;margin-right:24px}main{grid-template-columns:minmax(0,1fr) 294px}aside{padding-left:20px}.masthead-caption{font-size:7px;padding:0;letter-spacing:1.7px}h1{font-size:32px}.model-stamp{display:none}.transport{grid-template-columns:195px 1fr 160px;gap:24px}.phase-control{display:none}.speed-control{padding-left:17px}.viewer-caption{font-size:6px;gap:7px}.engine-title h2{font-size:25px}.pill{font-size:6px}}
@media(max-width:760px){.masthead{height:73px;margin:0 20px}.masthead-caption{display:none}.text-button{font-size:10px}.wordmark{font-size:9px}.wordmark svg{width:31px}main{display:flex;flex-direction:column;height:auto;margin:0 20px;min-height:0}.stage{height:745px;flex-shrink:0}.heading{top:30px}h1{font-size:34px;line-height:1.18;max-width:350px}.heading p{font-size:11px}h1 em{display:block}.eyebrow{font-size:8px}.view-bar{top:183px}#viewport,#labels{top:270px}.camera-tools{right:0;bottom:70px}.viewer-caption{bottom:20px;font-size:6px}.orientation{right:5px;bottom:13px}aside{border-left:0;border-top:1px solid var(--line);padding:28px 0 10px;display:grid;grid-template-columns:1fr 1fr;gap:24px;overflow:visible}.engine-card{grid-column:1 / -1}.engine-title{justify-content:flex-start;gap:20px}.description{max-width:none}.spec-grid{grid-template-columns:repeat(4,1fr)}.spec-grid strong{font-size:27px}.spec-grid small{font-size:10px}.spec-grid span{font-size:6px}.bore-stroke{max-width:300px}.section-kicker{font-size:8px}.section-kicker>span{display:none}aside section{border:0;margin:0}.cycle-card{grid-column:2;grid-row:2}.layers-card{grid-column:1;grid-row:2}.toggle-row{font-size:10px}.firing-order{gap:3px}.firing-order button{width:24px;height:27px;min-width:20px}.firing-order>span{font-size:6px}.firing-label>span{display:none}.cylinder-title{gap:7px}h3{font-size:16px}.cylinder-title>span{font-size:6px;letter-spacing:.7px}.transport{margin:0 20px;display:grid;grid-template-columns:1fr 1fr;gap:28px 20px;padding:25px 0 35px}.playback{grid-column:1;gap:8px}.playback #play{width:39px;height:39px}.playback>div>span{font-size:7px}.playback #step{padding:1px}.rpm-control{grid-column:2;grid-row:1}.speed-control{grid-column:1;border:0;padding-left:0}.speed-control select{max-width:180px}.phase-control{display:block;grid-column:2}.transport label{font-size:7px;letter-spacing:1px}.rpm-control output{font-size:20px}dialog{margin:20px;padding:30px 24px;max-height:85dvh}dialog h2{font-size:30px}dialog p{font-size:12px}.source-links{gap:16px}#toast{bottom:30px;white-space:nowrap}}

.study-nav{display:flex;align-items:center;gap:26px}.study-nav a{font-size:11px;text-decoration:none;color:#8fa5a8;padding:12px 0;border-bottom:1px solid transparent}.study-nav a.active{color:var(--accent);border-color:#718154}.study-nav small{font-size:8px;color:#6d898e;margin-right:8px}.study-nav a:hover{color:var(--text)}
@media(max-width:760px){.masthead{height:110px;flex-wrap:wrap;padding:14px 0 0;align-content:space-between}.study-nav{order:3;width:100%;justify-content:center;gap:25px;height:37px}.study-nav a{padding:8px 0;font-size:10px}.study-nav small{font-size:7px}.masthead .text-button{padding-top:4px;padding-bottom:4px}}
/* Keep the audio toggle easy to tap in Safari without selecting its label. */
.sound-control button{touch-action:manipulation;-webkit-user-select:none;user-select:none}
@media(max-width:760px){.sound-control button{min-height:44px}}