@import url('https://fonts.googleapis.com/css2?family=Nunito:wght@400;600;700;800;900&family=Noto+Sans+SC:wght@400;500;600;700;800;900&display=swap');
:root{--ink:#252d35;--muted:#68737c;--cream:#f7f7f2;--paper:#fffefa;--line:#e9e8df;--orange:#ee8e67;--teal:#31877e;--navy:#293646;--purple:#756bb0;--green:#48866f;--shadow:0 15px 40px rgba(43,58,65,.075);--radius:24px;font-family:'Nunito','Noto Sans SC',sans-serif;color:var(--ink);background:var(--cream);scroll-behavior:smooth;scroll-padding-top:86px}*{box-sizing:border-box}body{margin:0;background:var(--cream);font-size:15px;line-height:1.7}.skip-link{position:absolute;left:12px;top:-60px;z-index:10;background:#fff;padding:8px 14px;border-radius:8px;color:#123}.skip-link:focus{top:12px}a{color:inherit;text-decoration:none}button,input{font:inherit}button{cursor:pointer}.topbar{height:78px;padding:0 max(5.7vw,26px);display:flex;align-items:center;gap:34px;background:rgba(255,254,250,.88);backdrop-filter:blur(12px);position:sticky;top:0;z-index:5;border-bottom:1px solid rgba(43,58,65,.06)}.brand{display:flex;align-items:center;gap:10px;font-weight:900;font-size:17px;line-height:1.12;white-space:nowrap}.brand-mark{display:grid;place-items:center;width:38px;height:38px;border-radius:13px;background:#378d82;color:#fff}.brand-mark svg{width:30px;height:30px}.brand small{display:block;margin-top:5px;color:#87908f;font-size:10px;font-weight:700;letter-spacing:.06em}.topnav{display:flex;gap:30px;margin-left:auto;color:#637078;font-size:13px;font-weight:700}.topnav a:hover,.footer a:hover{color:var(--teal)}.nav-cta{padding:10px 17px;background:#283644;color:#fff;border-radius:30px;font-size:12px;font-weight:800}.nav-cta span{margin-left:8px;color:#ffd57f}.page-width{width:min(1110px,calc(100% - 52px));margin-inline:auto}.hero{width:min(1110px,calc(100% - 52px));min-height:485px;margin:30px auto 28px;padding:42px 66px 42px 71px;border-radius:31px;background:#fbecd9;display:grid;grid-template-columns:1.05fr .95fr;align-items:center;position:relative;overflow:hidden}.hero:before{content:"";position:absolute;width:340px;height:340px;border:1px solid rgba(203,131,86,.18);border-radius:50%;top:-215px;left:42%}.hero-copy{position:relative;z-index:1}.eyebrow{font-size:11px;letter-spacing:.16em;font-weight:900;color:#6b817d;text-transform:uppercase}.hero .eyebrow{color:#b86a4c;display:flex;align-items:center;gap:8px}.sparkle{display:grid;place-items:center;font-size:17px;color:#e69b45}.hero h1{font-size:clamp(35px,4vw,51px);line-height:1.29;letter-spacing:-.04em;margin:16px 0 15px;font-weight:900}.hero h1 em,.closing em{color:#c56b50;font-style:normal;position:relative;white-space:nowrap}.hero h1 em:after{content:"";position:absolute;left:0;right:0;bottom:1px;height:8px;background:#ffd58f;opacity:.7;z-index:-1;border-radius:8px}.hero-text{max-width:440px;color:#68726f;font-size:14px;line-height:1.95;margin:0 0 23px}.button{display:inline-flex;gap:19px;align-items:center;justify-content:center;border-radius:30px;padding:13px 20px;font-weight:900;font-size:13px;transition:transform .2s,box-shadow .2s}.button:hover{transform:translateY(-2px);box-shadow:0 9px 18px rgba(38,54,67,.15)}.button-primary{background:#293b49;color:white}.button-primary span{color:#ffd076;font-size:17px}.hero-proof{margin-top:19px;color:#747b74;font-size:11px;font-weight:700}.proof-dot{display:inline-grid;place-items:center;width:16px;height:16px;margin-right:5px;background:#88b296;color:#fff;border-radius:50%;font-size:10px}.hero-proof i{margin:0 5px;color:#c5a78b;font-style:normal}.hero-art{height:365px;position:relative;display:grid;place-items:center}.hero-art img{width:min(290px,71%);aspect-ratio:1;object-fit:cover;border-radius:39% 61% 58% 42%/45% 39% 61% 55%;position:relative;z-index:1;border:7px solid rgba(255,255,255,.75);box-shadow:0 20px 35px rgba(78,76,63,.12);animation:float 5s ease-in-out infinite}.art-blob{position:absolute;border-radius:50%;animation:float 6s ease-in-out infinite}.blob-a{width:300px;height:300px;background:#fad084;opacity:.48;transform:rotate(20deg)}.blob-b{width:65px;height:65px;background:#c3e3d3;top:36px;right:25px}.art-note,.art-caption{position:absolute;z-index:2;padding:10px 15px;background:#fffefa;border-radius:14px;box-shadow:0 10px 22px rgba(68,65,57,.1);font-size:12px;font-weight:800;animation:bob 4s ease-in-out infinite}.art-note span{color:#dc9e48;margin-right:3px}.note-one{top:41px;left:1px;transform:rotate(-6deg)}.note-two{bottom:91px;right:0;transform:rotate(5deg);animation-delay:.5s}.art-caption{bottom:16px;left:14%;padding:11px 17px;display:flex;flex-direction:column;line-height:1.45;transform:rotate(-2deg);animation-delay:.9s}.art-caption span{font-size:10px;color:#89928d}.art-caption strong{color:#4b736a}.hero-squiggle{position:absolute;right:6%;bottom:17px;color:#d8a46b;width:150px}.lesson-index{padding:34px 0 56px}.section-heading{display:flex;align-items:end;justify-content:space-between;margin-bottom:23px}.compact-heading h2,.lesson-title-row h2{font-size:26px;letter-spacing:-.035em;margin:4px 0 0;font-weight:900}.compact-heading>p{margin:0 0 4px;color:#85908a;font-size:12px}.index-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:13px}.index-card{display:flex;align-items:center;gap:12px;padding:16px 13px;background:#fffefa;border:1px solid rgba(56,65,69,.05);border-radius:16px;min-height:85px;transition:transform .2s,box-shadow .2s}.index-card:hover{transform:translateY(-4px);box-shadow:var(--shadow)}.index-icon{width:43px;height:43px;border-radius:15px;display:grid;place-items:center;font-size:22px;flex:none}.index-card b{display:block;font-size:13px;font-weight:900}.index-card small{display:block;margin-top:3px;color:#8c9691;font-size:10px;line-height:1.4}.index-arrow{margin-left:auto;color:#a7aca4;font-size:15px}.index-peach .index-icon{background:#fff0e6}.index-blue .index-icon{background:#e6f2ef}.index-lilac .index-icon{background:#f1edfb}.index-green .index-icon{background:#e9f3e9}.lesson-section{padding:17px 0 30px}.lesson-title-row{margin-bottom:24px}.progress-wrap{display:flex;align-items:center;gap:10px;color:#78827d;font-size:11px;font-weight:700}.progress-label{white-space:nowrap}.progress-track{height:8px;width:126px;border-radius:9px;background:#e4e6dc;overflow:hidden}.progress-fill{height:100%;width:0;background:#69a285;border-radius:inherit;transition:width .4s}.progress-wrap b{font-size:11px;color:#4b7963;min-width:31px}.lesson-card{--accent:#d97d5b;--accent-bg:#fff1e9;--accent-soft:#f7d9ca;--accent-dark:#a75c43;background:var(--paper);border:1px solid rgba(47,58,62,.07);border-radius:25px;box-shadow:0 8px 30px rgba(48,62,67,.045);margin-bottom:25px;overflow:hidden;scroll-margin-top:96px}.theme-blue{--accent:#4d948e;--accent-bg:#eaf6f2;--accent-soft:#d2eae3;--accent-dark:#34776e}.theme-lilac{--accent:#8a7dc0;--accent-bg:#f4f0fc;--accent-soft:#e5dcf5;--accent-dark:#66599b}.theme-green{--accent:#719e71;--accent-bg:#f0f6ec;--accent-soft:#d9e8d2;--accent-dark:#537d56}.lesson-head{display:flex;align-items:center;gap:17px;padding:26px 30px 22px;border-bottom:1px solid #f0efe9}.lesson-number{width:51px;height:51px;border-radius:17px;background:var(--accent-bg);color:var(--accent-dark);display:grid;place-items:center;font-size:16px;font-weight:900;flex:none}.lesson-head-copy{flex:1}.lesson-tags{display:flex;gap:7px;align-items:center;margin-bottom:5px}.lesson-tags span{font-size:9px;font-weight:900;letter-spacing:.04em;color:var(--accent-dark);background:var(--accent-bg);padding:3px 8px;border-radius:20px}.lesson-tags span+span{color:#9ba39d;background:#f3f2ed}.lesson-head h3{font-size:19px;letter-spacing:-.02em;margin:0 0 4px;font-weight:900}.lesson-head-copy p{font-size:12px;color:#7e8985;margin:0}.lesson-doodle{width:134px;height:86px;border-radius:21px;background:var(--accent-bg);display:flex;align-items:center;justify-content:center;gap:9px;font-size:31px;flex:none;position:relative;overflow:hidden}.lesson-doodle:after{content:"";position:absolute;width:66px;height:66px;border:1px solid var(--accent-soft);border-radius:50%;right:-23px;top:-32px}.lesson-doodle span{font-size:12px;color:var(--accent-dark);font-weight:900}.doodle-tree{font-size:30px}.doodle-ruler{font-size:28px;color:#8a7dc0}.doodle-candy{font-size:27px}.lesson-content{display:grid;grid-template-columns:1.07fr .93fr;gap:19px;padding:22px 24px 25px}.explainer,.play-panel{min-width:0}.explainer{padding:5px 8px 3px 6px}.story-label{display:inline-flex;align-items:center;gap:7px;font-size:10px;font-weight:900;letter-spacing:.04em;color:var(--accent-dark);background:var(--accent-bg);border-radius:20px;padding:5px 10px}.story-icon{font-size:13px}.big-question{font-size:14px;line-height:1.9;margin:11px 0 13px;color:#4b5457}.big-question strong{color:#273843;font-size:17px;font-weight:900}.steps{display:none;margin:8px 0 10px;padding:2px 0}.steps.is-open{display:block;animation:appear .35s ease both}.step{display:flex;align-items:flex-start;gap:10px;margin:10px 0;color:#596466;font-size:12px;line-height:1.8}.step>span{width:22px;height:22px;display:grid;place-items:center;background:var(--accent-bg);color:var(--accent-dark);border-radius:8px;font-size:10px;font-weight:900;flex:none}.step p{margin:0}.step b{color:#303b41;font-weight:900}.text-button{border:0;background:transparent;padding:5px 0;color:var(--accent-dark);font-size:11px;font-weight:900}.text-button span{font-size:15px;margin-left:3px;display:inline-block;transition:transform .2s}.text-button[aria-expanded=true] span{transform:rotate(45deg)}.answer-line{border-top:1px dashed #dfded5;margin-top:14px;padding-top:12px;display:flex;align-items:center;gap:8px;flex-wrap:wrap}.answer-line>span:first-child{font-size:9px;background:var(--accent-bg);color:var(--accent-dark);padding:3px 7px;border-radius:10px;font-weight:900}.answer-line>b{font-size:12px}.answer-check{font-size:9px;color:#8b9790;margin-left:auto}.play-panel{background:#faf9f5;border:1px solid #f0efe8;border-radius:19px;padding:18px 18px 14px}.panel-top{display:flex;justify-content:space-between;gap:10px;align-items:center}.panel-kicker{display:block;font-size:9px;color:#9aa29d;font-weight:900;letter-spacing:.1em}.panel-top h4{margin:2px 0 0;font-size:14px;line-height:1.55;font-weight:900}.panel-top h4 span{color:var(--accent-dark);font-size:18px}.interactive-badge{padding:4px 9px;border:1px solid #e7e5dd;border-radius:20px;color:#87938c;font-size:9px;font-weight:900;white-space:nowrap}.panel-help{font-size:10px;color:#8b9590;margin:8px 0}.rabbit-slider-row{display:flex;justify-content:space-between;align-items:center;gap:7px;font-size:9px;font-weight:800;color:#88928c}.rabbit-slider-row input{accent-color:#db8664;width:47%;cursor:pointer}.leg-meter{height:14px;background:#e6e7df;border-radius:12px;overflow:hidden;margin:12px 2px 5px}.leg-meter-fill{height:100%;width:0%;background:linear-gradient(90deg,#f7c782,#e78968);border-radius:12px;transition:width .35s cubic-bezier(.2,.7,.3,1)}.meter-labels{display:flex;justify-content:space-between;font-size:9px;color:#9ca39e}.meter-labels b{color:var(--accent-dark)}.target-callout{display:flex;align-items:center;gap:8px;padding:8px 10px;margin-top:11px;border-radius:10px;background:#fff;font-size:10px;color:#7a8580;min-height:36px}.target-dot{height:8px;width:8px;border-radius:50%;background:#efbc69;flex:none}.target-callout.is-match{background:#eaf5ec;color:#4c795b}.target-callout.is-match .target-dot{background:#69a77d;box-shadow:0 0 0 4px #d5ebdb}.mini-challenge{border-top:1px dashed #dfdfd8;margin-top:13px;padding-top:10px}.mini-challenge>strong{font-size:9px;color:var(--accent-dark);background:var(--accent-bg);padding:3px 7px;border-radius:9px}.mini-challenge label{display:block;margin:6px 0 7px;font-size:11px;font-weight:700;color:#535e60;line-height:1.6}.answer-input-row{display:flex;gap:7px}.answer-input-row input{min-width:0;width:110px;height:34px;border:1px solid #dedfd7;border-radius:9px;background:#fff;padding:5px 10px;font-size:11px;outline:none}.answer-input-row input:focus{border-color:var(--accent);box-shadow:0 0 0 3px var(--accent-bg)}.answer-input-row input::placeholder{color:#bbc0ba}.check-button{height:34px;border:0;padding:0 14px;background:var(--accent);border-radius:9px;color:#fff;font-size:10px;font-weight:900;transition:filter .2s,transform .2s}.check-button:hover{filter:brightness(.95);transform:translateY(-1px)}.quiz-result{min-height:15px;margin:5px 0 0;font-size:10px;color:#7f8a84}.quiz-result.correct{color:#398060;font-weight:800}.quiz-result.try-again{color:#c17354}.tree-mode{display:flex;gap:7px;margin:10px 0 1px}.mode-button{border:1px solid #e2e5df;background:#fff;border-radius:20px;padding:6px 11px;font-size:9px;font-weight:900;color:#82908b}.mode-button.is-active{background:#4d948e;border-color:#4d948e;color:#fff}.tree-visual{height:139px;margin:6px 0 0;border-radius:14px;background:#f1f8f4;overflow:hidden;display:grid;place-items:center}.tree-visual svg{width:100%;height:100%}.path-line{stroke:#91c6b3;stroke-width:5;stroke-linecap:round;stroke-dasharray:3 8}.tree-canopy{fill:#71a983;transform-box:fill-box;transform-origin:center;animation:tree-pop .5s both}.tree-trunk{fill:#9c7658}.interval-marks{stroke:#55988f;stroke-width:1.4;fill:#668b81;font:10px 'Nunito','Noto Sans SC',sans-serif}.interval-marks text{stroke:none;text-anchor:middle;font-weight:800}.tree-explanation{padding:11px 12px 8px;background:#f8fbf7;border-radius:12px;margin:10px 0}.tree-equation{display:flex;align-items:center;gap:6px;flex-wrap:wrap;font-weight:900;color:#65726c;font-size:12px}.tree-equation strong{color:#427a6c;font-size:12px}.tree-equation .tree-result{padding:4px 7px;border-radius:7px;background:#dff0e5}.tree-equation .tree-plus{color:#789b7d;font-size:10px}.tree-rule{margin:5px 0 0;font-size:10px;color:#85918a}#tree-rule{margin:4px 0 0;font-size:10px;color:#85918a}.tree-rule-card{display:flex;align-items:center;gap:12px;background:#fff;border-radius:13px;padding:12px;margin:17px 0 11px}.tree-rule-icon{height:42px;width:42px;border-radius:13px;background:#eaf5ef;display:grid;place-items:center;font-size:21px}.tree-rule-card b{font-size:12px}.tree-rule-card p{margin:3px 0 0;color:#458172;font-size:12px;font-weight:900}.visual-legend{display:flex;gap:16px;font-size:9px;color:#8c9690;margin:12px 2px}.visual-legend span{display:flex;align-items:center;gap:5px}.legend-tree,.legend-gap{width:10px;height:10px;background:#71a983;border-radius:4px}.legend-gap{width:15px;height:2px;border-radius:2px;background:#7fb4a2}.tip-box{border:1px solid #e9eee6;background:#f5f8f1;border-radius:12px;padding:11px 12px;font-size:10px;color:#68786e;line-height:1.75;margin:12px 0}.tip-box b{color:#50775c}.bar-visual{background:#f8f7fc;border-radius:15px;padding:17px 14px 11px;margin:10px 0 5px}.bar-row{display:grid;grid-template-columns:38px 1fr 27px;align-items:center;gap:8px;margin-bottom:12px;font-size:10px;color:#757d82}.bar-row>b{font-size:11px;color:#655a90}.bar-track{height:20px;display:flex;position:relative}.bar-part{height:100%;background:#ab9dd5;border-radius:7px 0 0 7px;width:63%;animation:growbar .9s cubic-bezier(.2,.7,.2,1) both;transform-origin:left}.bar-extra{width:25%;background:#e4a4ab;border-radius:0 7px 7px 0;display:grid;place-items:center;overflow:visible;position:relative;animation-delay:.2s}.bar-extra span{position:absolute;top:-17px;right:-4px;white-space:nowrap;color:#bd7682;font-size:8px;font-weight:900}.bar-empty{width:25%}.bar-key{display:flex;gap:14px;border-top:1px dashed #e2dfec;padding-top:8px;font-size:8px;color:#928e9d}.bar-key span{display:flex;align-items:center;gap:5px}.bar-key i{width:10px;height:7px;border-radius:3px;background:#ab9dd5}.bar-key span+span i{background:#e4a4ab}.sumdiff-formula{display:grid;grid-template-columns:1fr 20px 1fr;align-items:center;gap:7px;margin:18px 0 14px}.sumdiff-formula>div{background:#fff;border:1px solid #eeeaf6;border-radius:14px;padding:12px;text-align:center}.sumdiff-formula small{display:block;color:#8d88a1;font-size:9px;font-weight:800}.sumdiff-formula b{display:block;color:#6e6596;font-size:11px;margin:5px 0}.sumdiff-formula strong{display:block;font-size:22px;color:#4f776e}.formula-arrow{text-align:center;color:#b2a7d0}.candy-scene{display:grid;gap:8px;margin:12px 0;background:#f7faf3;border-radius:16px;padding:12px}.candy-case{background:#fff;border-radius:12px;padding:8px 10px}.candy-case-head{display:flex;justify-content:space-between;align-items:center;color:#89938d;font-size:9px}.candy-case-head b{color:#537b57;font-size:10px}.candy-row{display:flex;align-items:center;gap:2px;margin-top:3px}.candy-row i{font-style:normal;font-size:14px;animation:bob 3s ease-in-out infinite}.candy-row i:nth-child(2){animation-delay:.18s}.candy-row i:nth-child(3){animation-delay:.36s}.candy-row i.fade-candy{opacity:.35}.candy-row>span:nth-of-type(1){color:#9aa49c;font-size:10px;margin:0 3px}.surplus-pill,.short-pill{margin-left:auto;padding:3px 6px;border-radius:8px;background:#eaf5e6;color:#5a855d;font-size:8px;font-weight:900;white-space:nowrap}.short-pill{background:#fff0e6;color:#bd8059}.profit-equation{display:flex;align-items:center;justify-content:center;gap:8px;padding:16px 0 12px;color:#7d887e;font-weight:900}.profit-token{width:47px;height:47px;border-radius:15px;display:grid;place-items:center;background:#e7f2df;transform:rotate(-5deg)}.profit-token span{font-size:10px;color:#5a855d}.short-token{background:#fff0e4;transform:rotate(5deg)}.short-token span{color:#bc805a}.profit-total{display:flex;flex-direction:column;align-items:center}.profit-total strong{font-size:20px;line-height:1.2;color:#537b57}.profit-total small{font-size:8px;color:#939c91}.person-equation{padding:10px 9px;border-radius:11px;background:#fff;display:flex;align-items:center;gap:5px;flex-wrap:wrap;font-size:9px;color:#8c968d}.person-equation b{color:#527753;font-size:11px}.person-equation i{font-style:normal;color:#c4c8bd;margin-inline:auto}.person-equation strong{color:#537b57;font-size:11px}.closing{position:relative;overflow:hidden;display:flex;align-items:center;gap:28px;margin-top:32px;margin-bottom:32px;padding:32px 42px;background:#e4f0e7;border-radius:23px}.closing-star{display:grid;place-items:center;width:53px;height:53px;flex:none;border-radius:17px;background:#fff;color:#e5a74e;font-size:30px}.closing .eyebrow{color:#648a70}.closing h2{font-size:21px;line-height:1.45;margin:5px 0 5px;font-weight:900}.closing em{color:#4d8163}.closing p{font-size:11px;color:#6f8274;margin:0}.button-dark{margin-left:auto;background:#31494a;color:#fff;white-space:nowrap;z-index:1}.button-dark span{color:#b7dfc1}.closing-decoration{position:absolute;right:13%;top:-10px;display:flex;gap:12px;align-items:center;color:#8fbea0;opacity:.37;font-weight:900;font-size:24px;transform:rotate(-10deg)}.closing-decoration span:first-child{font-size:43px}.closing-decoration span:last-child{font-size:50px;color:#e7a864}.about{display:grid;grid-template-columns:220px 1fr;gap:7px 34px;padding:28px 0 36px;border-top:1px solid #e7e7dd}.about h2{font-size:19px;margin:5px 0;font-weight:900}.about>p{font-size:11px;line-height:1.9;color:#7b8580;margin:1px 0 8px}.about>p strong{color:#61766a}.source-note{grid-column:2}.source-note a{color:#46897f;text-decoration:underline;text-underline-offset:2px}.footer{padding:18px max(5.7vw,26px);min-height:74px;display:flex;align-items:center;justify-content:space-between;border-top:1px solid #e9e8df;background:#fffefa;color:#939b95;font-size:10px}.footer-brand{color:var(--ink);font-size:13px}.footer-brand .brand-mark{width:31px;height:31px;border-radius:11px}.footer-brand .brand-mark svg{width:24px;height:24px}.footer-brand small{font-size:9px}.is-complete{box-shadow:0 0 0 2px rgba(89,150,110,.35),var(--shadow)}@keyframes float{0%,100%{transform:translateY(0) rotate(-1deg)}50%{transform:translateY(-9px) rotate(1deg)}}@keyframes bob{0%,100%{translate:0 0}50%{translate:0 -4px}}@keyframes appear{from{opacity:0;transform:translateY(-5px)}to{opacity:1;transform:translateY(0)}}@keyframes growbar{from{transform:scaleX(.25);opacity:.5}to{transform:scaleX(1);opacity:1}}@keyframes tree-pop{from{transform:scale(.65);opacity:.5}to{transform:scale(1);opacity:1}}@media(max-width:900px){.hero{padding:38px 38px;min-height:420px}.hero-art{height:310px}.index-grid{grid-template-columns:repeat(2,1fr)}.lesson-content{grid-template-columns:1fr 1fr;gap:12px;padding:19px}.lesson-head{padding:22px}.lesson-doodle{width:100px}.play-panel{padding:15px 13px}.about{grid-template-columns:180px 1fr;gap:7px 22px}}@media(max-width:650px){body{font-size:14px}.topbar{height:64px;padding:0 17px;gap:10px}.brand{font-size:14px}.brand-mark{width:34px;height:34px}.topnav{gap:13px;font-size:11px}.nav-cta{padding:9px 11px;font-size:10px}.topnav a:last-child{display:none}.page-width,.hero{width:calc(100% - 30px)}.hero{padding:29px 22px 15px;grid-template-columns:1fr;min-height:auto;border-radius:24px;margin-top:14px}.hero h1{font-size:36px;margin:10px 0}.hero-text{font-size:12px;line-height:1.8;margin-bottom:16px}.hero-proof{font-size:9px;margin-top:13px}.hero-art{height:254px;margin-top:0}.hero-art img{width:197px;border-width:5px}.blob-a{width:220px;height:220px}.blob-b{width:43px;height:43px;right:20%}.note-one{left:8%;top:25px}.note-two{right:7%;bottom:64px}.art-caption{left:13%;bottom:6px}.hero-squiggle{display:none}.lesson-index{padding:25px 0 32px}.section-heading{align-items:start;gap:12px;flex-direction:column}.compact-heading h2,.lesson-title-row h2{font-size:22px}.compact-heading>p{font-size:11px}.index-grid{gap:9px}.index-card{min-height:72px;padding:10px 8px;gap:8px;border-radius:13px}.index-icon{width:35px;height:35px;font-size:18px;border-radius:12px}.index-card b{font-size:11px}.index-card small{font-size:8px}.index-arrow{font-size:12px}.lesson-section{padding-top:10px}.lesson-title-row{margin-bottom:17px}.progress-wrap{width:100%;gap:8px}.progress-track{flex:1}.lesson-card{border-radius:19px;margin-bottom:17px}.lesson-head{padding:18px 15px 15px;gap:11px;align-items:flex-start}.lesson-number{width:39px;height:39px;border-radius:13px;font-size:12px}.lesson-head h3{font-size:15px;line-height:1.5}.lesson-head-copy p{font-size:10px;line-height:1.6}.lesson-doodle{display:none}.lesson-tags span{font-size:8px}.lesson-content{grid-template-columns:1fr;padding:13px 13px 15px;gap:11px}.explainer{padding:3px 3px 0}.big-question{font-size:12px}.big-question strong{font-size:15px}.step{font-size:11px}.play-panel{padding:15px 13px;border-radius:15px}.panel-top h4{font-size:13px}.answer-check{margin-left:0}.tree-visual{height:125px}.tree-equation{font-size:10px;gap:4px}.tree-equation strong{font-size:10px}.bar-visual{padding:14px 10px 9px}.sumdiff-formula{gap:4px}.sumdiff-formula>div{padding:9px 5px}.sumdiff-formula b{font-size:10px}.closing{padding:20px 17px;gap:13px;align-items:flex-start}.closing-star{width:40px;height:40px;font-size:23px;border-radius:14px}.closing h2{font-size:16px}.closing p{font-size:10px;max-width:220px}.button-dark{margin-left:0;margin-top:5px;padding:9px 12px;font-size:10px;gap:8px}.closing-decoration{right:6%;opacity:.2}.about{grid-template-columns:1fr;gap:8px;padding:21px 0}.about h2{font-size:17px}.about>p,.source-note{grid-column:1;font-size:10px}.footer{padding:14px 16px;gap:12px;flex-wrap:wrap}.footer>span{display:none}.footer-brand{font-size:11px}.footer-brand .brand-mark{width:27px;height:27px}.footer>a:last-child{font-size:10px}}@media(prefers-reduced-motion:reduce){*,*::before,*::after{scroll-behavior:auto!important;animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important}}

/* Clear, three-step entry for learners arriving at the home page. */
.start-here{padding:52px 0 40px}.start-here-heading{margin-bottom:20px}.start-here-heading h2{margin:8px 0 0;font-size:30px;letter-spacing:-.04em}.start-here-heading>p{max-width:310px;color:var(--muted);font-size:13px}.start-route-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}.start-route-card{position:relative;display:flex;flex-direction:column;min-height:220px;padding:22px;border:1px solid var(--line);border-radius:20px;background:var(--paper);box-shadow:0 10px 28px rgba(43,58,65,.055);transition:transform .18s ease,box-shadow .18s ease}.start-route-card:hover{transform:translateY(-3px);box-shadow:0 15px 32px rgba(43,58,65,.1)}.start-route-number{position:absolute;right:19px;top:16px;color:#d7ddd7;font-size:31px;font-weight:900;line-height:1}.start-route-tag{align-self:flex-start;padding:4px 9px;border-radius:999px;background:#edf4ef;color:#48816e;font-size:10px;font-weight:900}.route-application .start-route-tag{background:#fff0e8;color:#b66e4f}.route-number .start-route-tag{background:#eaf2f7;color:#4e7891}.route-practice .start-route-tag{background:#f0ecfb;color:#7564a5}.start-route-card h3{margin:17px 0 7px;font-size:18px;letter-spacing:-.02em}.start-route-card p{margin:0;color:var(--muted);font-size:12px;line-height:1.8}.start-route-link{display:flex;align-items:center;justify-content:space-between;margin-top:auto;padding-top:17px;color:var(--teal);font-size:12px;font-weight:900}.start-route-link i{font-size:17px;font-style:normal}.start-route-note{margin:15px 0 0;padding:12px 15px;border-left:3px solid #9ac0a7;border-radius:0 10px 10px 0;background:#f0f4eb;color:#56665d;font-size:12px}.start-route-note b{color:#315b4c}
@media(max-width:760px){.start-here{padding:36px 0 30px}.start-here-heading{align-items:flex-start}.start-here-heading h2{font-size:24px}.start-route-grid{grid-template-columns:1fr;gap:10px}.start-route-card{min-height:0;padding:18px}.start-route-card h3{margin-top:12px}.start-route-link{padding-top:12px}.start-route-note{font-size:11px;line-height:1.75}}