:root{--paper:#f7f6ef;--ink:#243d34;--green:#235d49;--muted:#65756b;--line:#dce1d3;--accent:#db8359;--font:"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;--serif:"Kaiti SC","STKaiti","KaiTi",serif;--radius:18px}
*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:110px}body{margin:0;background:var(--paper);color:var(--ink);font-family:var(--font);font-size:15px;line-height:1.7;-webkit-font-smoothing:antialiased}a{color:inherit;text-decoration:none}button,input,select{font:inherit;color:inherit}button,a,input,select{-webkit-tap-highlight-color:transparent}button{cursor:pointer}button:disabled{cursor:default;opacity:.55}a,button,input,select{outline-offset:5px}a:focus-visible,button:focus-visible,input:focus-visible,select:focus-visible,svg [role=button]:focus-visible{outline:3px solid #ce8050}a,button{touch-action:manipulation}button{border:1px solid var(--line);border-radius:9px;background:#fcfbf5;padding:9px 14px}button:hover{background:#ecefe3}h1,h2,h3,p{margin-top:0}h1,h2,h3{line-height:1.35;font-weight:650;letter-spacing:-.025em}h2{font-size:clamp(25px,3vw,33px);margin-bottom:13px}h3{font-size:20px;margin-bottom:9px}p{margin-bottom:18px}svg{display:block;width:100%;height:auto}svg text{font-family:var(--font);fill:var(--ink);font-size:14px}main{max-width:1200px;padding:0 32px;margin:auto;min-height:70vh}main:focus{outline:none}small{font-size:12px}.muted{color:var(--muted);font-size:14px}.eyebrow{font-size:12px;letter-spacing:.075em;font-weight:500;color:#64796d;display:block}.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap}.skip{position:fixed;top:-100px;left:20px;z-index:999;padding:10px 20px;background:var(--green);color:var(--paper)}.skip:focus{top:10px}
.header{border-bottom:1px solid var(--line);background:rgba(247,246,239,.97);position:sticky;top:0;z-index:10}.header-inner{max-width:1200px;padding:19px 32px 17px;display:flex;align-items:center;justify-content:space-between;margin:auto;gap:25px}.brand{display:flex;gap:12px;align-items:center;font-weight:700;font-size:20px;letter-spacing:.05em;white-space:nowrap}.brand-mark{font-size:44px;line-height:1;color:var(--green);font-weight:500}.brand small{display:block;font-size:10px;font-weight:400;letter-spacing:.12em;color:var(--muted);margin-top:0}.header nav{display:flex;align-items:center;gap:34px;font-size:14px}.header nav a{position:relative;padding:7px 0;color:var(--muted)}.header nav a.active{color:var(--green);font-weight:600}.header nav a.active:after{content:"";position:absolute;bottom:-20px;left:15%;right:15%;height:3px;background:var(--green)}.nav-dot{display:inline-block;width:5px;height:5px;background:var(--accent);border-radius:50%;margin-left:5px;vertical-align:top}.free-label{font-size:11px;letter-spacing:.05em;white-space:nowrap;color:var(--muted);display:flex;align-items:center;gap:8px}.free-label i,.live-label i{width:6px;height:6px;border-radius:50%;background:#7e9d6c;display:inline-block}
.btn{background:var(--green);color:#faf7e9;display:inline-flex;justify-content:center;align-items:center;gap:25px;padding:13px 22px;border-radius:9px;border:1px solid var(--green);font-size:14px;font-weight:550;line-height:1.5;min-height:48px;transition:background .18s,transform .18s}.btn:hover{background:#174534;transform:translateY(-1px)}.btn.secondary{background:transparent;color:var(--green);border-color:#9aafa0}.btn.secondary:hover{background:#e9eee2}.btn.small{padding:9px 14px;min-height:42px;gap:10px;font-size:13px}.text-link{font-size:13px;border-bottom:1px solid #b4bdb0;padding:3px 0;font-weight:500;white-space:nowrap}.text-link:hover{color:var(--accent);border-color:var(--accent)}.text-button{border:0;background:none;font-size:13px;text-decoration:underline;text-underline-offset:5px;padding:10px 0}.text-button:hover{background:none;color:var(--accent)}
.hero{display:grid;grid-template-columns:1fr 1.02fr;gap:40px;align-items:center;padding:55px 0 48px}.hero-copy{padding:0 0 5px 4px}.hero-eyebrow{display:flex;gap:9px;align-items:center;letter-spacing:.12em;margin-bottom:22px}.sunburst{font-size:23px;color:var(--accent);font-weight:400}.hero h1{font-size:clamp(45px,5.5vw,70px);letter-spacing:-.07em;line-height:1.28;font-weight:650;margin-bottom:20px}.handwritten{font-family:var(--serif);font-weight:500;color:var(--green);position:relative;letter-spacing:-.06em}.handwritten:after{content:"";position:absolute;bottom:1px;left:7px;right:-3px;height:5px;border-radius:50%;background:#e3bc69;transform:rotate(-3deg);z-index:-1}.hero-desc{font-size:16px;color:var(--muted);line-height:1.95;margin-bottom:25px}.hero-actions{display:flex;align-items:center;gap:23px}.hero-note{font-size:11px;color:#7b887b;margin-top:26px;display:flex;gap:10px;align-items:center;letter-spacing:.035em}.three-dots{display:flex}.three-dots i{width:16px;height:16px;background:#c4d2b4;border:2px solid var(--paper);border-radius:50%;margin-right:-4px}.three-dots i:nth-child(2){background:#e7c38b}.three-dots i:nth-child(3){background:#9ebeb9}.hero-art{display:block;position:relative;min-height:414px;border-radius:70% 55% 22px 22px/26% 23% 22px 22px;background:#e1edf0;padding:40px 8px 74px;overflow:hidden;border:1px solid #d2e1df}.hero-art .art{margin-top:30px;transform:scale(1.05)}.sticker{position:absolute;left:24px;top:28px;font-size:11px;letter-spacing:.08em;background:#f8f5e9;padding:5px 13px;border:1px solid #b8cbc4;border-radius:6px;transform:rotate(-5deg);z-index:1}.sticker span{margin-left:15px;color:#81958b;font-size:10px}.scribble{position:absolute;font-family:var(--serif);font-size:20px;line-height:1.5;color:#48747e;right:24px;top:75px;transform:rotate(8deg)}.art-caption{position:absolute;bottom:24px;left:28px;font-size:11px;letter-spacing:.06em;color:#66868a}.art-caption strong{display:block;font-family:var(--serif);font-size:20px;font-weight:600;letter-spacing:0;color:#376672}.art-caption strong span{padding:0 10px;color:#a2bfc0;font-size:15px}.art-open{position:absolute;right:25px;bottom:28px;width:37px;height:37px;background:#f7f7e8;border-radius:50%;display:grid;place-items:center;color:#527d7e}.hero-art:hover .art-open{background:#245b4d;color:#faf7ec}
.discovery-strip{display:flex;align-items:center;gap:29px;border-top:1px solid var(--line);border-bottom:1px solid var(--line);padding:20px 4px;font-size:12px;color:var(--muted)}.discovery-strip b{font-family:Georgia,serif;font-size:19px;color:var(--ink);margin-right:5px;font-weight:500}.discovery-strip a{margin-left:auto;font-size:11px;color:#809080}
.catalog{padding:58px 0 0;scroll-margin-top:100px}.section-heading{display:flex;justify-content:space-between;align-items:flex-end;gap:20px;margin-bottom:25px}.section-heading h2{margin:8px 0 0}.catalog-note{font-family:var(--serif);font-size:17px;color:#8a927a;margin-bottom:4px}.filters{display:flex;justify-content:space-between;gap:15px;align-items:center}.filter-subjects{display:flex;gap:5px;flex-wrap:wrap}.filter-subjects button{border-radius:30px;background:transparent;padding:7px 18px;border-color:transparent;font-size:13px;white-space:nowrap}.filter-subjects button.active{background:var(--green);color:#f9f7ea}.filter-subjects button:hover:not(.active){background:#e8eddf}.filter-inputs{display:flex;gap:10px}.search-wrap{display:flex;align-items:center;gap:10px;border:1px solid #d5ddcf;background:#fcfbf5;border-radius:8px;padding:5px 13px;min-width:0}.search-wrap>span{font-size:23px;line-height:1;color:#6c8070}.search-wrap input{border:0;background:transparent;padding:6px 0;width:210px;font-size:12px;outline-offset:2px;min-width:0}.search-wrap input::placeholder{color:#95a08f}.select-wrap{font-size:13px;display:inline-flex;align-items:center;gap:8px}.select-wrap select{padding:10px 28px 10px 12px;border-radius:8px;border:1px solid #d5ddcf;background:#fcfbf5;font-size:12px;max-width:100%}.filter-hint{font-size:11px;color:#88917f;margin:14px 0 20px}.lab-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:26px 22px}.lab-card{border:1px solid var(--line);border-radius:15px;overflow:hidden;min-width:0;background:#fcfbf6;transition:transform .22s,border-color .22s}.lab-card:hover{transform:translateY(-4px);border-color:#8eab94}.card-art{height:190px;position:relative;overflow:hidden;background:var(--tint)}.card-art .art{height:100%;object-fit:contain;transition:transform .3s}.lab-card:hover .art{transform:scale(1.035)}.card-tag{position:absolute;top:15px;left:17px;font-size:10px;background:#fcfbefc9;line-height:1;padding:6px 9px;border:1px solid #7c8c6825;border-radius:5px;color:#657669;letter-spacing:.05em}.card-body{padding:19px 21px 22px}.card-body .eyebrow{font-size:10px;letter-spacing:0;display:flex;justify-content:space-between;color:#8c957f}.card-body h3{font-size:20px;margin:7px 0 7px;display:flex;justify-content:space-between;align-items:center}.card-arrow{font-size:20px;font-weight:400;color:#8c9d8a}.card-body p{font-size:12px;margin:0;color:#74816d}.lab-card.featured{grid-column:span 2;display:grid;grid-template-columns:1.15fr 1fr;background:#ecf2f0}.lab-card.featured .card-art{height:100%;min-height:290px}.lab-card.featured .card-body{display:flex;justify-content:center;flex-direction:column;padding:25px}.lab-card.featured h3{font-size:25px;margin:14px 0}.lab-card.featured .eyebrow{display:block}.lab-card.featured .eyebrow span{display:block;margin-top:5px}.lab-card.featured p{font-size:14px;line-height:1.9}.blue{--tint:#e0edef;--tone:#4f8aa2}.orange{--tint:#f1e6d3;--tone:#b8895e}.yellow{--tint:#f0edda;--tone:#a38c4f}.purple{--tint:#ebe7ee;--tone:#92839d}.pink{--tint:#f1e4df;--tone:#ad858a}.green{--tint:#e7eddd;--tone:#7c9964}.mint{--tint:#e0e9df;--tone:#6c9883}.coral{--tint:#f1e8dc;--tone:#c29471}
.path-section{margin:62px 0 48px}.path-list{border-top:1px solid var(--line)}.path-row{display:flex;align-items:center;gap:26px;padding:23px 15px 23px 5px;border-bottom:1px solid var(--line);transition:background .2s}.path-row:hover{background:#edf0e5}.path-number{font-family:Georgia,serif;font-size:28px;color:#a7b3a0;width:45px;flex:none}.path-row h3{font-size:18px;margin-bottom:3px}.path-row p{font-size:12px;color:var(--muted);margin:0}.path-status{font-size:11px;color:#899580;margin-left:auto;white-space:nowrap}.path-arrow{font-size:23px;color:#899580;margin-left:10px}.parent-banner{display:flex;gap:25px;align-items:center;padding:29px 32px;background:#ecefdf;border-radius:12px;margin:35px 0 60px}.parent-banner>.sunburst{font-size:43px}.parent-banner h3{font-size:17px}.parent-banner p{font-size:12px;color:var(--muted);margin:0}.parent-banner .text-link{margin-left:auto;flex:none}footer{max-width:1136px;margin:0 auto;padding:24px 0 35px;border-top:1px solid var(--line);display:flex;align-items:center;gap:24px;flex-wrap:wrap;font-size:10px;color:#8c9784}footer .footer-brand{font-size:13px;font-weight:600;color:var(--green)}footer a:hover{color:var(--accent)}footer #offline-status{margin-left:auto;font-size:10px}
.page-heading{padding:53px 0 36px;max-width:890px}.page-heading h1{font-size:clamp(31px,4.5vw,48px);margin:14px 0}.page-heading p{color:var(--muted);font-size:14px;line-height:1.9;margin-bottom:0}.page-heading .back-link{display:block;margin-bottom:28px}.back-link{font-size:12px;color:#6c8070;display:inline-block;margin-bottom:22px}.back-link:hover{color:var(--accent)}.lab-header{padding-top:31px}.lab-title-row{display:flex;align-items:center;justify-content:space-between;gap:25px}.lab-header h1{font-size:clamp(30px,4vw,43px);margin:7px 0 14px}.lab-title-icon{color:#be9e59;font-size:27px;margin-left:20px;vertical-align:middle}.lab-header p{font-size:14px;color:var(--muted);margin-bottom:27px}.lab-completion{font-size:11px;padding:7px 14px;border-radius:30px;background:#eaeedf;color:#87937b;white-space:nowrap}.lab-completion.done{background:#dce9d9;color:#376548}.lab-tabs{display:flex;border-bottom:1px solid var(--line);gap:34px;margin-bottom:30px}.lab-tabs a{font-size:14px;padding:13px 5px 16px;color:#899480;position:relative;white-space:nowrap}.lab-tabs a>span{font-size:10px;font-family:Georgia,serif;letter-spacing:.05em;margin-right:8px}.lab-tabs a.active{color:var(--green);font-weight:600}.lab-tabs a.active:after{content:"";position:absolute;bottom:-1px;left:0;right:0;height:3px;background:var(--green)}.experiment-shell{display:grid;grid-template-columns:minmax(0,1fr) 300px;gap:24px;align-items:start}.experiment-playground{border:1px solid #d8e0d3;border-radius:16px;overflow:hidden;background:#fafbf3;min-width:0}.stage{background:var(--tint);min-height:335px;display:grid;align-items:center;position:relative;overflow:hidden;background-image:radial-gradient(#879d8a24 .7px,transparent .7px);background-size:17px 17px}.experiment-svg{width:100%;height:auto;min-height:315px;max-height:440px}.svg-large{font-size:26px;font-weight:650}.svg-emoji{font-size:42px}.observation{padding:24px 27px;min-height:168px}.observation h3{font-size:22px;margin:6px 0 10px}.observation p{font-size:13px;color:var(--muted);margin:0;line-height:1.9}.controls{border:1px solid var(--line);border-radius:14px;background:#fcfbf5;padding:21px 20px}.control-heading{font-size:15px;font-weight:600;display:flex;justify-content:space-between;align-items:center;gap:10px;margin-bottom:24px}.live-label{font-size:9px;color:#819179;font-weight:400;white-space:nowrap;display:flex;align-items:center;gap:5px}.range-label{display:flex;align-items:center;justify-content:space-between;font-size:12px;gap:9px;margin:18px 0 5px}.range-label output{font-size:12px;font-weight:600;color:var(--green)}input[type=range]{width:100%;height:28px;accent-color:var(--green);cursor:pointer;margin:2px 0 8px;padding:0}.controls h3{font-size:11px;color:#7c8976;margin:20px 0 8px;font-weight:500}.controls .segmented{display:flex;gap:4px;background:#f0f1e7;border-radius:7px;padding:4px}.segmented button{flex:1;border:0;background:none;font-size:11px;padding:7px 5px;min-height:36px;border-radius:5px}.segmented button[aria-pressed=true]{background:#fdfbf1;color:#2f664c;box-shadow:0 1px 3px #45643a16}.presets{display:flex;gap:7px;flex-wrap:wrap;margin-top:13px}.presets button{font-size:10px;padding:6px 9px;border-radius:6px}.presets button[aria-pressed=true]{border-color:var(--green);background:#e5ecdf}.control-tip{font-size:11px;color:#85907c;line-height:1.9;margin:17px 0 10px}.range-ends{display:flex;justify-content:space-between;font-size:9px;color:#8b957e}.challenge-box{border-top:1px dashed #d7decb;padding-top:18px;margin-top:20px}.challenge-box .eyebrow{font-size:10px;color:#b18b58}.challenge-box p{font-size:12px;margin:7px 0 10px;line-height:1.8}.challenge-box strong{font-size:11px;font-weight:500;color:#969b88}.challenge-box strong.done{color:#45714d}.record-btn{width:100%;font-size:12px;margin-top:15px;padding:10px 12px}.model-note{font-size:11px;color:#85907f;line-height:1.9;margin:19px 0 0;padding:0 2px}.model-note strong{font-weight:500;margin-right:6px}.learning-bottom{border-top:1px solid var(--line);border-bottom:1px solid var(--line);padding:25px 0;margin-top:28px;display:flex;align-items:center;justify-content:space-between;gap:24px}.learning-bottom p{font-size:14px;color:var(--muted);margin:0}.learning-bottom .eyebrow{font-size:10px;margin-bottom:5px}.recent-observations{padding:31px 0 45px}.recent-observations h3{font-size:17px}.recent-observations h3 small{font-weight:400;color:#97a18e;margin-left:10px}.observation-entry{padding:15px 0;border-bottom:1px dashed var(--line);font-size:12px;color:#627561;overflow-wrap:anywhere}.observation-entry time{font-size:10px;display:block;color:#98a38d;margin-bottom:6px}.particle{transform-box:fill-box;transform-origin:center;animation:drift var(--speed) ease-in-out infinite alternate;animation-delay:var(--delay)}.particle.frozen{--dx:1px!important;--dy:1px!important;--speed:.4s!important}.bubble{animation:rise 2s ease-in infinite}@keyframes drift{to{transform:translate(var(--dx),var(--dy))}}@keyframes rise{to{transform:translateY(-45px);opacity:0}}
.fraction-stage{display:flex;align-items:center;justify-content:center;gap:14px;padding:38px 24px;min-height:350px}.fraction-piece{flex:1;min-width:0;text-align:center}.fraction-piece>.eyebrow{font-size:10px;margin-bottom:15px}.fraction-bar{display:grid;height:95px;border:2px solid #aa9270;border-radius:7px;overflow:hidden}.fraction-bar button{border:0;border-right:1px solid #aa9270;border-radius:0;min-width:0;padding:0;transition:background .2s}.fraction-bar button:last-child{border:0}.fraction-bar button:hover{filter:brightness(.97)}.fraction-bar button span{font-size:8px;color:#fcf6e3}.fraction-number{width:35px;margin:15px auto 9px;font-family:Georgia,serif;font-size:24px;line-height:1.4}.fraction-number>span{display:block}.fraction-number>span:first-child{border-bottom:2px solid #63745a}.fraction-piece>span:last-child{font-size:10px;color:#7c876c}.compare-symbol{font-size:30px;color:#8c957c;margin-top:-50px}.eco-buttons{display:flex;gap:7px;flex-wrap:wrap;margin:10px 0}.eco-buttons button{font-size:11px;padding:7px 9px;flex:1;white-space:nowrap}.eco-buttons .btn{font-size:11px;padding:8px 9px}.learn-intro,.quiz-intro{padding:18px 0 23px;max-width:780px}.learn-intro h2,.quiz-intro h2{margin-top:10px;font-size:28px}.learn-intro p,.quiz-intro p{font-size:13px;color:var(--muted)}.concept-list{max-width:870px}.concept{display:flex;gap:28px;border-top:1px solid var(--line);padding:29px 0}.concept-number{font:27px Georgia,serif;color:#a2b49a;min-width:38px}.concept h3{font-size:23px;margin-bottom:13px}.concept p{font-size:15px;line-height:2;color:#536a5b;margin-bottom:18px}.try-it{font-size:12px;padding:13px 17px;background:#edf0e3;border-radius:6px;color:#76836c;line-height:1.9}.try-it strong{font-weight:500;color:#5e7759;display:block;margin-bottom:2px}.concept-source{font-size:10px;display:inline-block;margin-top:14px;color:#8e9a83;border-bottom:1px solid #c8d1bf}.lab-content{margin-bottom:52px}.quiz-intro{padding-bottom:10px}#quiz-form{max-width:850px}.quiz-question{border:0;border-top:1px solid var(--line);padding:24px 0 30px;margin:8px 0 22px;min-width:0}.quiz-question legend{font-size:17px;font-weight:600;padding:0 20px 0 0;max-width:100%}.quiz-question legend>span{font:19px Georgia,serif;color:#b5b99f;margin-right:15px}.quiz-options{display:grid;gap:10px}.quiz-options label{display:flex;gap:14px;align-items:center;border:1px solid #dfe2d4;border-radius:10px;background:#fcfbf5;padding:14px 17px;font-size:13px;cursor:pointer}.quiz-options label:has(input:checked){border-color:#7a9b7b;background:#e9efdf}.quiz-options input{accent-color:var(--green);margin:0}.option-letter{font-family:Georgia,serif;color:#8b9b7e}.question-feedback{font-size:12px;padding:14px 17px;border-radius:8px;margin-top:13px;line-height:1.9}.question-feedback.correct{color:#406a43;background:#e7efdd}.question-feedback.incorrect{color:#98653e;background:#f2e8d6}.quiz-result{margin:25px 0;padding:25px;background:#e7eddd;border-radius:12px}.quiz-result h3{font-size:22px}.quiz-result p{font-size:13px;color:var(--muted)}.quiz-result a{margin-right:24px}
.progress-overview{display:flex;gap:35px;align-items:center;padding:30px 0 45px;border-bottom:1px solid var(--line);margin-bottom:36px}.progress-overview h2{font-size:25px}.progress-overview p{font-size:13px;color:var(--muted)}.progress-ring{width:148px;height:148px;border-radius:50%;background:conic-gradient(#77936a var(--progress),#e2e7d9 0);display:grid;place-items:center;flex:none;position:relative}.progress-ring:after{content:"";position:absolute;inset:9px;border-radius:50%;background:var(--paper)}.progress-ring strong{z-index:1;font:43px Georgia,serif;text-align:center}.progress-ring small{display:block;font:11px var(--font);margin-top:4px;color:#88977a}.achievement-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:15px;margin-top:23px}.achievement{display:flex;align-items:center;gap:20px;border:1px solid var(--line);border-radius:12px;padding:14px;transition:background .2s;min-width:0}.achievement:hover{background:#eff1e6}.achievement-art{width:114px;flex:none;background:var(--tint);border-radius:9px;filter:saturate(.6)}.achievement.unlocked .achievement-art{filter:none}.achievement>div:last-child{flex:1;min-width:0}.achievement h3{font-size:17px;display:flex;justify-content:space-between;gap:12px}.achievement h3>span{color:#adb89d;font-size:19px}.achievement.unlocked h3>span{color:#ba934c}.achievement p{font-size:11px;color:#7c8b71;margin:0 0 4px}.achievement .muted{font-size:10px}.notebook{padding:32px;background:#edf0e3;margin:40px 0;border-radius:14px}.notebook p{font-size:13px;color:var(--muted);max-width:750px}.notebook-actions{display:flex;gap:15px;align-items:center;flex-wrap:wrap}.file-label{position:relative;cursor:pointer}.file-label input{position:absolute;opacity:0;width:100%;height:100%;inset:0;cursor:pointer}.file-label:has(input:focus-visible){outline:3px solid #ce8050;outline-offset:4px}#import-status{font-size:12px;color:#a36c45;margin-top:15px}.all-observations{margin:40px 0 50px}.all-observations h2{font-size:25px}.all-observations article{margin:24px 0}.all-observations h3{font-size:17px}.path-journey{display:flex;flex-direction:column;gap:25px;margin-bottom:60px}.journey-stop{display:flex;gap:27px;align-items:center;border-top:1px solid var(--line);padding:25px 0}.journey-index{font:28px Georgia,serif;color:#acb89f;min-width:32px}.journey-art{width:235px;background:var(--tint);border-radius:15px}.journey-stop h2{font-size:26px;margin:8px 0}.journey-stop p{font-size:13px;color:var(--muted)}
.map-top{display:flex;justify-content:space-between;gap:15px;align-items:center}.map-explainer{font-size:12px;color:var(--muted);margin-top:17px}.map-controls{display:flex;gap:14px;align-items:center;margin:25px 0 20px}.map-controls .search-wrap{flex:1;max-width:450px}.map-controls input{width:100%}#map-count{font-size:12px;color:#8f9b82;margin-left:auto}.map-layout{display:grid;grid-template-columns:minmax(0,1fr) 320px;gap:25px;margin-bottom:55px;align-items:start}.map-board{min-width:0}.graph-art{background:#edf0e4;border:1px solid #dce2d0;border-radius:13px;padding:7px 6px}.graph-art svg{height:auto;max-height:410px}.graph-art svg text{font-size:9px;fill:#6d7e64}.graph-art g[role=button]{cursor:pointer}.graph-art g[role=button]:hover circle{fill:#d09b65;stroke:#4a745a}.map-legend{display:flex;gap:14px;flex-wrap:wrap;font-size:9px;color:#859379;padding:12px 0;margin-bottom:10px}.map-legend>span{display:flex;gap:5px;align-items:center}.map-legend i{width:6px;height:6px;background:#d4a267;border-radius:50%;display:inline-block}.map-legend>span:nth-child(2) i{background:#76a391}.map-legend>span:nth-child(3) i{background:#9995b6}.topic-list{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px;max-height:500px;overflow:auto;scrollbar-width:thin;padding:2px}.topic-item{border:1px solid #e0e5d5;text-align:left;padding:11px 12px;display:flex;gap:10px;align-items:center;min-width:0}.topic-item.selected{background:#e6eddd;border-color:#7a9c76}.topic-dot{display:block;width:7px;height:7px;background:#9995b6;border-radius:50%;flex:none}.topic-dot.science{background:#76a391}.topic-dot.math{background:#d4a267}.topic-item>span:nth-child(2){min-width:0;flex:1}.topic-item strong{font-size:11px;font-weight:500;display:block;line-height:1.6;overflow-wrap:anywhere}.topic-item small{font-size:8px;display:block;color:#8c987f;margin-top:5px}.topic-item>span:last-child{color:#a0ab92;font-size:12px;flex:none}.topic-detail{padding:23px 21px;background:#fcfbf5;border:1px solid var(--line);border-radius:13px;min-width:0}.topic-detail h2{font-size:23px;overflow-wrap:anywhere;margin:8px 0}.topic-detail p{font-size:12px;color:#6e8068;line-height:1.95;overflow-wrap:anywhere}.topic-detail .english-name{font-size:10px;color:#9da58f;margin-bottom:14px}.topic-detail .eyebrow{font-size:9px}.topic-detail .btn{font-size:12px;margin-bottom:10px;width:100%;padding:11px 12px}.topic-detail .topic-meta{font-size:9px;color:#9aa48a;margin:8px 0}.prereq-section{border-top:1px solid var(--line);margin-top:21px;padding-top:21px}.prereq-section h3{font-size:15px}.prereq{display:block;width:100%;text-align:left;padding:10px 0;border-radius:0;border:0;border-bottom:1px dashed var(--line);background:none}.prereq:hover{background:#f2f3e8}.prereq strong{font-size:11px;display:block;font-weight:500;line-height:1.7}.prereq span{font-size:8px;color:#a78b56;display:block;margin:5px 0}.prereq small{display:block;font-size:9px;color:#9aa58f;line-height:1.8}.checkbox-label{font-size:10px;display:flex;gap:7px;align-items:center}.checkbox-label input{accent-color:var(--green)}.prereq-section>.muted{font-size:9px;margin:11px 0}.planned-path{padding-left:19px;max-height:280px;overflow:auto;margin:15px 0 20px}.planned-path li{font-size:10px;margin-bottom:8px;color:#9baa8e}.planned-path button{font-size:10px;border:0;background:none;padding:0;text-align:left;line-height:1.8;border-radius:0}.planned-path button:hover{color:var(--accent)}.topic-detail .data-id{font-size:8px;margin:15px 0 0;color:#a5ad9a}.topic-detail details{font-size:11px;color:#839279;margin-bottom:15px}.topic-detail details ul{padding-left:18px;line-height:1.9;font-size:10px}.topic-detail summary{cursor:pointer}
.about-page{max-width:790px;margin:50px auto 70px}.about-page>.eyebrow{margin:35px 0 12px}.about-page>a:first-child{font-size:12px;color:#839177}.about-page h1{font-size:clamp(31px,4.5vw,44px);line-height:1.6;margin-bottom:22px}.about-page h2{font-size:23px;margin:38px 0 15px}.about-page p{font-size:14px;line-height:2.15;color:#65765f}.about-page p.lead{font-size:17px}.about-page p a{text-decoration:underline;text-underline-offset:4px;color:#3f775a}.about-page code{font-size:11px;overflow-wrap:anywhere;background:#e9ecdf;padding:2px 4px}.about-back{padding-top:24px}.empty-state{padding:65px 30px;text-align:center;grid-column:1/-1;color:#829073}.empty-state h1{font-size:30px}.empty-state h3{color:#536f55}.empty-state p{font-size:13px}.loading{padding:70px 20px;text-align:center;color:#8f9e80;font-size:13px}.noscript{max-width:800px;margin:40px auto;padding:30px;background:#eee4d0}#toast{position:fixed;bottom:26px;left:50%;max-width:calc(100vw - 30px);width:max-content;transform:translate(-50%,16px);background:#2d5947;color:#f8f5e8;font-size:12px;padding:13px 22px;border-radius:10px;z-index:100;opacity:0;pointer-events:none;transition:opacity .2s,transform .2s;box-shadow:0 5px 24px #1d45261a}#toast.show{opacity:1;transform:translate(-50%,0)}
@media(min-width:1280px){.hero{gap:65px}.hero-art{min-height:435px}.hero-copy{padding-left:10px}}
@media(max-width:1000px){.header-inner{gap:20px}.header nav{gap:22px}.free-label{display:none}.hero{gap:25px;padding-top:42px}.hero-art{min-height:370px;padding-bottom:73px}.hero-art .art{margin-top:41px}.scribble{font-size:17px;right:18px;top:85px}.hero h1{font-size:55px}.hero-actions{gap:15px}.hero-actions .text-link{font-size:11px}.discovery-strip{gap:20px;font-size:10px}.discovery-strip a{display:none}.filters{align-items:flex-start}.filter-inputs{gap:7px}.search-wrap input{width:180px}.card-art{height:165px}.card-body{padding:17px}.card-body h3{font-size:18px}.lab-card.featured .card-body{padding:19px}.lab-card.featured h3{font-size:23px}.experiment-shell{grid-template-columns:minmax(0,1fr) 270px;gap:18px}.controls{padding:18px 16px}.stage{min-height:300px}.experiment-svg{min-height:280px}.map-layout{grid-template-columns:minmax(0,1fr) 285px;gap:18px}.topic-list{grid-template-columns:1fr}.topic-detail{padding:21px 17px}.parent-banner{padding:25px;gap:18px}.parent-banner .text-link{font-size:11px}footer{margin:0 32px}.achievement-art{width:90px}.achievement{gap:14px}.achievement h3{font-size:15px}}
@media(max-width:760px){main{padding:0 22px}.header-inner{padding:14px 22px;flex-wrap:wrap;gap:12px}.brand{font-size:18px}.brand-mark{font-size:37px}.brand small{font-size:9px}.header nav{gap:24px;font-size:12px;margin-left:auto}.header nav a.active:after{bottom:-16px}.hero{gap:20px;padding-top:32px;padding-bottom:32px}.hero h1{font-size:45px}.hero-eyebrow{font-size:10px;margin-bottom:16px}.hero-desc{font-size:12px;line-height:2}.hero-actions{display:block}.hero-actions .btn{font-size:12px;min-height:43px;padding:12px 17px}.hero-actions .text-link{display:block;width:max-content;margin-top:14px}.hero-note{font-size:9px;line-height:1.8}.hero-art{min-height:320px;padding-bottom:90px}.hero-art .art{margin-top:50px;transform:scale(1.15)}.scribble{font-size:14px;right:15px;top:60px}.sticker{left:13px;top:22px;font-size:9px;padding:5px 8px}.sticker span{margin-left:7px;font-size:8px}.art-caption{bottom:24px;left:19px;font-size:9px}.art-caption strong{font-size:16px}.art-caption strong span{font-size:10px;padding:0 4px}.art-open{right:17px;bottom:30px;width:28px;height:28px}.discovery-strip{gap:12px;justify-content:space-between}.discovery-strip>span{font-size:9px}.discovery-strip b{font-size:17px;display:block;line-height:1.5}.catalog{padding-top:36px}.catalog-note{font-size:14px}.section-heading{margin-bottom:20px}.filters{flex-wrap:wrap}.filter-inputs{margin-left:auto}.filter-subjects button{padding:6px 12px;font-size:12px}.search-wrap input{width:210px}.lab-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:17px}.lab-card.featured{grid-column:span 2;grid-template-columns:1fr 1fr}.lab-card.featured .card-art{min-height:210px}.card-art{height:170px}.card-body .eyebrow{font-size:9px}.card-body h3{font-size:19px}.card-body p{font-size:11px}.parent-banner{flex-wrap:wrap;gap:14px}.parent-banner>div{flex:1;min-width:70%}.parent-banner .text-link{margin-left:55px}.path-row{gap:15px}.path-row p{font-size:11px}.path-status{font-size:10px}.path-number{width:34px}.path-section{margin:42px 0}.path-row h3{font-size:17px}.section-heading .text-link{font-size:11px}footer{margin:0 22px;gap:13px 20px;padding-bottom:26px}footer #offline-status{margin-left:0;flex-basis:100%}.lab-title-row{align-items:flex-start}.lab-completion{font-size:9px;padding:7px 10px;margin-top:20px}.lab-header p{font-size:13px}.lab-tabs{gap:25px}.lab-tabs a{font-size:13px}.experiment-shell{grid-template-columns:1fr;gap:18px}.stage{min-height:320px}.experiment-svg{min-height:300px;max-height:370px}.controls{padding:24px}.controls .range-label{font-size:14px}.controls .segmented button{font-size:13px;min-height:40px}.controls h3{font-size:12px}.presets button{font-size:12px}.controls .control-tip{font-size:12px}.controls .challenge-box p{font-size:13px}.record-btn{font-size:13px}.controls .control-heading{margin-bottom:19px}.observation{padding:22px}.observation h3{font-size:21px}.learning-bottom .btn{font-size:12px;gap:10px;padding:11px 15px}.learning-bottom p{font-size:12px}.achievement-grid{grid-template-columns:1fr}.achievement-art{width:120px}.achievement h3{font-size:18px}.progress-overview{gap:25px}.progress-overview h2{font-size:22px}.progress-ring{width:126px;height:126px}.notebook{padding:25px}.notebook h2{font-size:25px}.map-layout{grid-template-columns:1fr}.topic-list{grid-template-columns:repeat(2,minmax(0,1fr));max-height:350px}.topic-detail{padding:25px}.topic-detail h2{font-size:26px}.topic-detail p{font-size:14px}.topic-detail .english-name{font-size:11px}.topic-detail .topic-meta{font-size:10px}.prereq strong{font-size:13px}.prereq small{font-size:11px}.prereq-section>.muted{font-size:11px}.planned-path button{font-size:12px}.planned-path li{font-size:12px}.checkbox-label{font-size:12px}.map-controls{gap:10px}.map-controls .search-wrap{flex:1}.map-controls #map-count{display:none}.map-top{align-items:flex-start;flex-wrap:wrap}.map-top .text-button{font-size:10px}.map-top .filter-subjects button{font-size:11px}.topic-item strong{font-size:12px}.topic-item small{font-size:9px}.journey-art{width:180px}.journey-stop{gap:17px}.journey-stop h2{font-size:23px}.journey-stop p{font-size:12px}.journey-index{min-width:20px;font-size:22px}.page-heading{padding-top:35px}.about-page{margin-top:32px}.concept{gap:18px}.concept h3{font-size:21px}.concept p{font-size:14px}.quiz-question legend{font-size:16px}}
@media(max-width:480px){main{padding:0 18px}.header-inner{padding:12px 18px 0;gap:10px;display:block}.brand{width:max-content;font-size:18px;gap:9px}.brand-mark{font-size:34px}.brand small{font-size:8px}.header nav{justify-content:space-between;gap:20px;margin:9px 0 0;padding:0 3px;font-size:12px}.header nav a{padding:9px 0 12px}.header nav a.active:after{bottom:0;left:0;right:0;height:2px}.hero{grid-template-columns:1fr;gap:25px;padding-top:29px;padding-bottom:28px}.hero-copy{padding:0}.hero-eyebrow{margin-bottom:13px}.hero h1{font-size:49px;line-height:1.2;margin-bottom:18px}.hero h1 br{display:block}.hero h1 .handwritten{white-space:nowrap}.hero-desc{font-size:13px;margin-bottom:18px}.hero-actions{display:flex;gap:20px}.hero-actions .text-link{margin-top:0;font-size:10px}.hero-note{margin-top:18px;font-size:9px}.hero-art{min-height:255px;height:255px;border-radius:65% 45% 15px 15px/27% 23% 15px 15px;padding:0 25px 46px}.hero-art .art{height:232px;margin-top:10px;transform:scale(1)}.scribble{top:70px;right:16px;font-size:16px}.sticker{left:18px;top:24px}.art-caption{left:20px;bottom:15px}.art-caption strong{font-size:16px}.art-open{bottom:20px}.hero-note .three-dots i{width:14px;height:14px}.discovery-strip{padding:13px 0;gap:8px}.discovery-strip>span{font-size:9px;letter-spacing:-.02em}.discovery-strip b{font-size:18px}.catalog{padding-top:31px}.section-heading h2{font-size:25px}.section-heading .eyebrow{font-size:10px}.catalog-note{display:none}.filters{gap:13px}.filter-inputs{width:100%;margin:0;display:flex;gap:8px}.filter-inputs .search-wrap{flex:1;padding:3px 11px;min-width:0}.filter-inputs .search-wrap input{width:100%;font-size:11px}.select-wrap select{font-size:11px;padding:10px 23px 10px 10px}.filter-subjects{gap:4px}.filter-subjects button{font-size:11px;padding:7px 15px}.filter-hint{font-size:9px;margin:12px 0 17px}.lab-grid{gap:15px 12px}.card-art{height:120px}.card-tag{font-size:8px;padding:5px 7px;top:10px;left:10px}.card-body{padding:13px 12px 15px}.card-body .eyebrow{font-size:8px;display:block}.card-body .eyebrow span{margin-left:6px}.card-body h3{font-size:16px;margin:6px 0}.card-arrow{font-size:15px}.card-body p{font-size:10px;line-height:1.9}.lab-card.featured .card-art{min-height:190px}.lab-card.featured .card-body{padding:13px}.lab-card.featured h3{font-size:20px;margin:10px 0}.lab-card.featured p{font-size:11px}.lab-card.featured .eyebrow{font-size:9px}.lab-card{border-radius:11px}.section-heading{gap:12px;align-items:center}.section-heading .text-link{font-size:9px}.path-section{margin-top:36px}.path-row{gap:13px;padding:20px 0}.path-number{font-size:23px;width:25px}.path-row h3{font-size:16px}.path-row p{font-size:10px;max-width:210px;line-height:1.8}.path-status{display:none}.path-arrow{margin-left:auto;font-size:21px}.parent-banner{padding:23px 18px;margin-bottom:35px}.parent-banner>div{min-width:65%}.parent-banner>.sunburst{font-size:32px}.parent-banner h3{font-size:15px}.parent-banner p{font-size:11px;line-height:1.9}.parent-banner .text-link{font-size:10px;margin-left:46px}footer{margin:0 18px;font-size:9px;gap:12px 17px}footer .footer-brand{font-size:12px}footer>span:first-of-type{margin-left:auto}footer #offline-status{font-size:9px}.page-heading h1{font-size:31px}.page-heading p{font-size:12px}.page-heading .eyebrow{font-size:10px}.lab-header{padding-top:22px}.back-link{margin-bottom:19px;font-size:11px}.lab-header h1{font-size:31px;margin-bottom:14px}.lab-title-icon{font-size:19px;margin-left:13px}.lab-title-row{position:relative;display:block}.lab-header .eyebrow{font-size:9px;padding-right:65px}.lab-completion{position:absolute;right:0;top:-6px;margin:0;font-size:8px;padding:5px 8px}.lab-header p{font-size:12px;line-height:1.9;margin-bottom:19px}.lab-tabs{gap:0;justify-content:space-between;margin-bottom:21px}.lab-tabs a{font-size:12px;padding:12px 3px}.lab-tabs a>span{font-size:9px;margin-right:6px}.experiment-svg{min-height:225px;max-height:none}.stage{min-height:235px}.stage svg text{font-size:15px}.stage svg .svg-large{font-size:25px}.stage svg .svg-emoji{font-size:42px}.observation{padding:20px}.observation h3{font-size:20px}.observation p{font-size:12px;line-height:1.9}.observation .eyebrow{font-size:10px}.controls{padding:22px}.controls .range-label{font-size:13px}.controls .presets button{font-size:11px}.controls .segmented button{font-size:12px}.control-tip{font-size:11px!important}.model-note{font-size:10px}.learning-bottom{gap:17px}.learning-bottom p{font-size:11px}.learning-bottom .btn{font-size:11px;padding:10px 12px;min-height:43px;white-space:nowrap}.fraction-stage{padding:29px 16px;gap:10px;min-height:270px}.fraction-bar{height:78px}.fraction-piece>.eyebrow{font-size:8px}.fraction-piece>span:last-child{font-size:8px}.compare-symbol{font-size:23px}.fraction-number{font-size:22px;width:30px}.learn-intro h2,.quiz-intro h2{font-size:25px}.learn-intro p,.quiz-intro p{font-size:12px}.concept{gap:13px;padding:24px 0}.concept-number{font-size:23px;min-width:26px}.concept h3{font-size:21px}.concept p{font-size:14px}.try-it{font-size:11px;padding:11px 14px}.quiz-question{padding-top:20px}.quiz-question legend{font-size:15px;line-height:1.8}.quiz-question legend>span{font-size:17px;margin-right:9px}.quiz-options label{font-size:12px;padding:13px 12px;gap:10px}.question-feedback{font-size:11px}.quiz-result{padding:23px 19px}.quiz-result h3{font-size:21px}.quiz-result a{display:inline-block;margin-top:8px;font-size:11px}.progress-overview{gap:19px;padding:15px 0 30px}.progress-ring{width:97px;height:97px}.progress-ring strong{font-size:33px}.progress-ring small{font-size:9px}.progress-ring:after{inset:7px}.progress-overview h2{font-size:20px}.progress-overview p{font-size:11px}.progress-overview .btn{padding:10px 16px;font-size:11px;min-height:42px}.achievement-art{width:100px}.achievement h3{font-size:17px}.achievement p{font-size:10px}.notebook{padding:24px 20px}.notebook h2{font-size:23px}.notebook p{font-size:12px}.notebook-actions{gap:11px}.notebook-actions .btn{font-size:11px;padding:11px 14px;min-height:42px}.notebook-actions .text-button{font-size:11px}.achievement-grid{gap:11px}.section-heading .select-wrap{font-size:10px;white-space:nowrap}.section-heading .select-wrap select{font-size:10px}.map-top .filter-subjects{gap:3px;width:100%}.map-top .filter-subjects button{font-size:10px;padding:8px 12px}.map-top .text-button{font-size:10px}.map-explainer{font-size:11px}.map-controls{gap:8px;margin-top:20px}.map-controls .search-wrap{padding:5px 10px}.map-controls input{font-size:11px}.map-controls .select-wrap{max-width:114px}.map-legend{font-size:8px;gap:8px 11px;line-height:1.8}.topic-list{grid-template-columns:1fr;max-height:310px}.topic-item{padding:11px 12px}.topic-item strong{font-size:12px}.topic-item small{font-size:9px}.topic-detail{padding:25px 22px}.topic-detail p{font-size:13px}.topic-detail .eyebrow{font-size:9px}.journey-stop{gap:12px;flex-wrap:wrap;position:relative}.journey-index{position:absolute;top:35px;left:10px;font-size:19px;z-index:1;color:var(--green)}.journey-art{width:100%;height:170px;overflow:hidden}.journey-art .art{height:100%;width:100%}.journey-stop>div:last-child{padding:6px 0}.journey-stop h2{font-size:23px}.about-page h1{font-size:31px}.about-page h2{font-size:22px}.about-page p{font-size:13px}.about-page p.lead{font-size:15px}.graph-art svg text{font-size:10px}#toast{font-size:11px;bottom:17px;padding:13px 17px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{animation:none!important;transition:none!important}svg animateMotion{display:none}}
@media print{.header,footer,.notebook,.achievement-grid,.progress-overview,.section-heading,.page-heading .eyebrow,#toast{display:none}body{background:#fff;color:#222}main{max-width:none;padding:0}.page-heading{padding:0}.page-heading h1{font-size:26px}.all-observations{margin:15px 0}.all-observations article{break-inside:avoid}.observation-entry{font-size:11px}.page-heading p{font-size:11px}.all-observations h2{font-size:20px}}

@media(max-width:480px){.hero-desc{font-size:14px}.card-body h3{font-size:17px}.card-body p{font-size:12px}.card-body .eyebrow{font-size:9px}.lab-card.featured p{font-size:12px}.quiz-options label{font-size:14px}.quiz-question legend{font-size:16px}.quiz-intro p,.learn-intro p{font-size:13px}.controls .range-label{font-size:14px}.controls .segmented button{font-size:13px}.observation p{font-size:14px}.observation h3{font-size:21px}.stage svg text{font-size:21px}.stage svg .svg-large{font-size:31px}.stage svg .svg-emoji{font-size:48px}.challenge-box p{font-size:14px!important}.model-note{font-size:11px}.parent-banner p{font-size:12px}.concept-source{font-size:11px}.question-feedback{font-size:13px}}