:root{--ink:#183f39;--muted:#5c716b;--green:#235e4e;--lime:#d9eea7;--paper:#f6f8f2;--line:#dce4da;--blue:#72b4c7}*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font-family:ui-rounded,'Avenir Next','Trebuchet MS',sans-serif;font-size:16px;line-height:1.5}button,input,select,textarea{font:inherit}button{cursor:pointer}button,input,select,textarea,summary{touch-action:manipulation}button:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible,summary:focus-visible,a:focus-visible{outline:3px solid #b46e15;outline-offset:4px}button{border:0;border-radius:12px;padding:12px 18px;font-weight:700;color:var(--ink);background:#edf2e8}button:disabled{cursor:default;opacity:.45}header{height:92px;max-width:1480px;padding:0 40px;margin:auto;display:flex;align-items:center;gap:32px;border-bottom:1px solid var(--line)}.brand{display:flex;align-items:center;gap:12px;font-weight:850;font-size:25px;color:var(--ink);text-decoration:none;letter-spacing:-1px}.brand-icon{font-size:34px;background:var(--green);color:var(--lime);width:44px;height:44px;border-radius:14px;display:grid;place-items:center}.edition{font-size:12px;font-weight:800;letter-spacing:1.7px;margin-left:auto}.edition span{margin:0 10px;color:#879981}.secondary{border:1px solid #bacbbd;background:transparent}main{max-width:1440px;margin:auto;padding:32px 40px}.intro{display:flex;align-items:center;justify-content:space-between;gap:20px;margin-bottom:22px}.eyebrow{font-size:11px;letter-spacing:1.8px;font-weight:800;color:var(--muted)}h1{font-size:clamp(28px,3vw,42px);line-height:1.15;letter-spacing:-1.4px;margin:7px 0 10px}p{margin:0}.intro p{color:var(--muted);font-size:18px}.cycle{display:flex;gap:4px;background:#e8eee2;padding:6px;border-radius:28px;font-size:14px;font-weight:700}.cycle span{padding:9px 15px;border-radius:22px;white-space:nowrap}.cycle .active{background:var(--green);color:white}.onboarding{display:flex;justify-content:space-between;align-items:center;gap:20px;padding:12px 18px;margin-bottom:24px;background:#eaf1dc;border:1px solid #d5e2bf;border-radius:12px;font-size:14px}.onboarding button{padding:6px 12px;background:transparent;text-decoration:underline;white-space:nowrap}.workspace{display:grid;grid-template-columns:330px minmax(0,1fr);gap:22px}.panel{background:#fff;border:1px solid var(--line);border-radius:20px;overflow:hidden;box-shadow:0 4px 15px #1d412705}.controls{padding:24px}.section-heading{display:flex;align-items:center;gap:10px;margin-bottom:20px}h2{font-size:20px;line-height:1.3;letter-spacing:-.4px;margin:0}h3{font-size:16px;margin:0 0 4px}.step{width:28px;height:28px;border-radius:50%;background:#e9efdf;display:grid;place-items:center;font-size:12px;font-weight:800;flex-shrink:0}.hint{font-size:14px;color:var(--muted)}.tiny{font-size:12px;color:var(--muted)}fieldset{padding:0;border:0;margin:0;min-width:0}legend{font-size:14px;font-weight:700;margin-bottom:14px}.slider{margin-bottom:15px}.slider label{display:flex;align-items:center;gap:8px;font-size:14px;font-weight:700}.slider output{margin-left:auto;font-size:12px;background:#edf3eb;padding:2px 7px;border-radius:5px}.range-labels{display:flex;justify-content:space-between;font-size:11px;color:var(--muted)}input[type=range]{accent-color:var(--green);width:100%;height:20px;margin:6px 0 0;cursor:pointer}.divider{height:1px;background:var(--line);margin:20px 0}.organism{display:flex;align-items:center;gap:9px;padding:10px 0;border-bottom:1px solid #eef1eb}.organism:last-child{border:0}.organism-icon{font-size:27px;width:35px;text-align:center}.organism-name{font-size:14px;font-weight:700;line-height:1.25}.role{display:block;font-size:11px;font-weight:400;color:var(--muted);margin-top:3px}.counter{margin-left:auto;display:flex;align-items:center;gap:7px}.counter button{width:30px;height:32px;padding:0;border-radius:8px;background:#eef3e9;font-size:19px}.counter output{min-width:12px;text-align:center;font-size:14px;font-weight:700}.controls>.tiny{display:block;margin-top:10px}.scene-heading{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:22px 26px}.scene-heading h2{font-size:24px;margin-top:3px}.pill{font-size:12px;font-weight:700;background:#f0f4e9;padding:7px 12px;border-radius:18px;white-space:nowrap}.scene{height:405px;position:relative;overflow:hidden;background:#d1e4d2}.scene>img{width:100%;height:100%;object-fit:cover;display:block}.scene-caption{position:absolute;bottom:15px;left:20px;max-width:calc(100% - 40px);font-size:12px;font-weight:700;color:#244d43;background:#ffffffe6;border-radius:20px;padding:6px 13px}.creature{position:absolute;filter:drop-shadow(0 3px 2px #173b3930);font-size:clamp(24px,3vw,42px);animation:float 4s ease-in-out infinite;transition:opacity .5s,transform .5s}.creature.plant{font-size:38px}.creature.decomposer{font-size:25px}.scene #weather-overlay{position:absolute;inset:0;background:#c79b5940;opacity:0;pointer-events:none;transition:opacity 1s}.timeline{padding:18px 26px;border-bottom:1px solid var(--line);display:flex;gap:20px;align-items:center}.timeline>.eyebrow{max-width:80px;font-size:10px}#years{display:flex;flex-wrap:wrap;gap:6px;flex:1;justify-content:space-between}#years button{padding:9px 10px;background:transparent;font-size:13px;border:1px solid transparent;white-space:nowrap}#years button.selected{background:var(--green);color:white}#years button:not(:disabled):hover{border-color:#789585}.stats{padding:20px 26px;display:flex;gap:30px;align-items:center}.health{display:flex;gap:10px;align-items:center;min-width:165px}.health strong{display:block;font-size:16px}.health-icon{width:42px;height:42px;border-radius:50%;display:grid;place-items:center;background:#eaf1d8;color:var(--green);font-size:23px}#populations{display:flex;flex:1;gap:18px}.population{flex:1;min-width:0}.population label{display:block;font-size:12px;font-weight:700}.bar{height:7px;background:#eef2e8;border-radius:8px;margin:7px 0;overflow:hidden}.bar span{display:block;height:100%;background:#67975c;border-radius:8px;transition:width .6s}.population:nth-child(2) .bar span{background:#d6a44c}.population:nth-child(3) .bar span{background:#639aad}.population small{font-size:11px;color:var(--muted)}.scene-note{background:#f5f8f0;border-top:1px solid var(--line);padding:14px 26px;font-size:14px;min-height:50px}.challenge-section{margin:28px 0}.challenge-section .section-heading{margin-bottom:14px}.spark{font-size:24px;color:#b68a35}.challenge-section .hint{margin-left:auto}#challenges{display:grid;grid-template-columns:repeat(5,1fr);gap:12px}.challenge{display:flex;align-items:flex-start;text-align:left;gap:10px;border:1px solid #d9e0d2;background:#f0f3e9;padding:16px 13px;min-height:91px}.challenge[aria-pressed=true]{border:2px solid var(--green);padding:15px 12px;background:#e0edcb}.challenge .symbol{font-size:23px}.challenge strong{font-size:14px;display:block}.challenge small{font-size:12px;line-height:1.5;color:var(--muted);display:block;margin-top:3px}.experiment{padding:24px 28px;display:flex;gap:35px;align-items:center}.prediction{flex:1}.prediction .section-heading{margin-bottom:14px}input:not([type=range]):not([type=checkbox]),select,textarea{width:100%;border:1px solid #cbd6c8;background:#fafcf7;color:var(--ink);border-radius:9px;padding:11px 12px;min-height:44px}#prediction{width:47%;margin-right:2%;font-size:14px}#prediction-text{width:50%;font-size:14px}#prediction-error:empty{display:none}#prediction-error{margin-top:8px;color:#963f24}.run-area{display:flex;align-items:center;gap:8px;flex-direction:column;min-width:240px}.primary{background:var(--green);color:#fff;padding:14px 22px}.primary:hover{background:#174838}#run{width:100%;font-size:18px}.results{padding:28px;margin-top:24px}.results .pill{margin-left:auto}.explanation{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}.finding{background:#f0f5e9;border-radius:12px;padding:18px}.finding h3{font-size:17px;margin-bottom:8px}.finding p{font-size:14px}.comparison{margin:20px 0;padding:16px 20px;border-left:4px solid #d7ac51;background:#fcf7e9;font-size:15px}.reflection{border-top:1px solid var(--line);padding-top:20px}.sentence-grid{display:grid;grid-template-columns:1fr 1fr 1.4fr;gap:16px;margin-top:16px}.sentence-grid label,.teacher-grid label{font-size:14px;font-weight:700}.sentence-grid input,.sentence-grid textarea,.teacher-grid input,.teacher-grid select{display:block;margin-top:6px;font-size:14px}.teacher{margin-top:24px;box-shadow:none}summary{padding:18px 24px;cursor:pointer;font-weight:700;font-size:14px}summary span{float:right;color:var(--muted);font-weight:400}.teacher form{border-top:1px solid var(--line);padding:24px}.teacher-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:16px;margin:16px 0 24px}.teacher-grid input[type=checkbox]{width:auto;display:inline}.check{display:block;margin:15px 0}.check input{accent-color:var(--green);width:18px;height:18px;vertical-align:middle}#teacher-status{margin-left:16px;font-size:14px}footer{display:flex;justify-content:space-between;gap:20px;margin-top:28px;font-size:12px;color:var(--muted)}footer>span{font-size:10px;font-weight:800;letter-spacing:1.5px}.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}[hidden]{display:none!important}@keyframes float{50%{transform:translateY(-4px)}}@media(prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important}}@media(min-width:1450px){.scene{height:450px}}@media(max-width:1100px){header{padding:0 24px}.edition{display:none}header .secondary{margin-left:auto}main{padding:24px}.workspace{grid-template-columns:290px 1fr}.controls{padding:20px}.scene{height:390px}.stats{flex-direction:column;align-items:stretch;gap:15px}.health{justify-content:center}.timeline{padding:16px 10px;gap:5px}.timeline>.eyebrow{display:none}#challenges{grid-template-columns:repeat(3,1fr)}.experiment{gap:20px}.prediction input#prediction-text,.prediction select#prediction{width:100%;margin:0 0 8px}.cycle{display:none}}@media(max-width:720px){header{height:auto;min-height:80px;padding:16px;gap:12px}.brand{font-size:20px}.brand-icon{display:none}header button{font-size:12px;padding:10px}main{padding:22px 16px}.intro p{font-size:16px}.workspace{display:flex;flex-direction:column}.controls{order:2}.habitat{order:1}.scene{height:310px}.scene-heading{padding:18px}.scene-heading h2{font-size:21px}.scene-heading .pill{font-size:10px}.onboarding{font-size:13px}.challenge-section .section-heading{flex-wrap:wrap}.challenge-section .hint{margin-left:0;width:100%}#challenges{grid-template-columns:1fr 1fr}.experiment{display:block;padding:22px}.run-area{margin-top:14px}.explanation,.sentence-grid{grid-template-columns:1fr}.teacher-grid{grid-template-columns:1fr 1fr}.results{padding:22px}summary span{display:none}footer{display:block}footer p{margin-top:8px}.stats{padding:18px}#years{gap:0}#years button{padding:8px 5px;font-size:12px}.results .section-heading{flex-wrap:wrap}.results .pill{margin-left:0}}@media(max-width:380px){.teacher-grid{grid-template-columns:1fr}.brand{font-size:18px}#challenges{grid-template-columns:1fr}.scene-heading{flex-wrap:wrap}} 

/* Habitat placement: never crop the coordinate-mapped backdrop. */
.scene{height:auto!important;aspect-ratio:3/2;isolation:isolate}
.scene>img{position:absolute;inset:0;object-fit:contain}
#living-layer{position:absolute;inset:0;pointer-events:none}
.scene-caption{top:14px;bottom:auto;z-index:110}
.habitat-organism{position:absolute;aspect-ratio:1;transform:translate(-50%,-90%);pointer-events:none}
.organism-art{display:block;width:100%;height:100%;background-size:300% 200%;background-repeat:no-repeat}
.zone-surface .organism-art{animation:water-bob 5s ease-in-out infinite}
.zone-bank .organism-art{animation:none}
.underwater-view{display:grid;grid-template-columns:minmax(160px,1fr) 2fr;align-items:stretch;background:#e5f1ee;border-bottom:1px solid #cbded7}
.underwater-description{padding:16px 20px}
.underwater-description .eyebrow{font-size:10px;color:#34635e}
.underwater-description strong{display:block;font-size:15px;margin:3px 0}
.underwater-description p{font-size:12px;line-height:1.45;color:#3d635e;max-width:240px}
.underwater-window{position:relative;min-height:125px;overflow:hidden;background:linear-gradient(180deg,#d4eae6 0%,#91bdb9 78%,#6b8880 79%,#61786b 100%)}
#underwater-layer{position:absolute;inset:8px 8px 15px}
.underwater-window .habitat-organism{width:11%!important;max-width:80px}
.cutaway-label{position:absolute;top:8px;right:12px;font-size:10px;color:#315753;letter-spacing:.3px}
#underwater-empty{position:absolute;top:52%;left:50%;transform:translate(-50%,-50%);font-size:12px;color:#284f49;white-space:nowrap}
.habitat-key{border-bottom:1px solid var(--line);background:#fafcf7}
.habitat-key summary{padding:11px 24px;font-size:13px;color:#345a4e}
.habitat-key p{padding:0 24px 12px;font-size:13px;line-height:1.6}
.habitat-key p.tiny{font-size:12px;color:var(--muted)}
@keyframes water-bob{0%,100%{transform:translateY(0)}50%{transform:translateY(-1.5px)}}
@media(max-width:720px){.underwater-view{grid-template-columns:1fr}.underwater-description{padding:12px 16px}.underwater-description p{max-width:none}.underwater-window{min-height:110px}.scene-caption{font-size:10px;padding:4px 9px;top:9px;left:10px}.habitat-key summary{padding:11px 16px}}
@media(prefers-reduced-motion:reduce){.zone-surface .organism-art{animation:none}}