:root{--ink:#142b46;--muted:#526780;--blue:#1769c2;--teal:#087f71;--line:#d8e3ee;--pale:#eff6fc;--white:#fff;font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;color:var(--ink);background:#f7fafd;font-synthesis:none}*{box-sizing:border-box}body{margin:0;font-size:16px;line-height:1.65}a{color:var(--blue);text-underline-offset:4px}button,input,select,textarea{font:inherit}button,.button{display:inline-flex;align-items:center;justify-content:center;gap:8px;padding:10px 17px;border:1px solid var(--line);background:white;border-radius:8px;color:var(--ink);font-weight:650;text-decoration:none;cursor:pointer;min-height:44px}button:hover,.button:hover{border-color:var(--blue);background:var(--pale)}button:disabled{opacity:.6;cursor:not-allowed}.primary{background:var(--blue);border-color:var(--blue);color:#fff}.primary:hover{background:#10569e;color:white}.dark{background:var(--ink);color:#fff}.skip{position:absolute;left:12px;top:-100px;background:#fff;padding:10px;z-index:20}.skip:focus{top:8px}:focus-visible{outline:3px solid #e49000;outline-offset:4px}header{height:92px;display:flex;align-items:center;justify-content:space-between;gap:20px;padding:0 38px;border-bottom:1px solid var(--line);background:#fff}.brand{display:flex;align-items:center;gap:12px;text-decoration:none;font-size:21px;font-weight:750;color:var(--ink)}.brand small{display:block;font-size:10px;letter-spacing:1.5px;color:var(--muted)}.brand-icon{display:grid;place-content:center;background:var(--blue);color:white;font-size:22px;line-height:1.1;border-radius:10px;padding:8px 11px}.brand-icon span{font-size:10px;letter-spacing:2px}header nav{display:flex;align-items:center;gap:24px;font-size:14px}.layout{display:grid;grid-template-columns:260px minmax(0,1fr);max-width:1600px;margin:auto}aside{padding:34px 24px;background:#fff;border-right:1px solid var(--line)}.edition{font-size:11px;letter-spacing:1px;color:var(--muted);display:flex;align-items:center;gap:10px}.edition b{background:#dcefff;color:var(--blue);padding:2px 6px;border-radius:4px}.course-title{font-size:28px;line-height:1.15;font-weight:800;letter-spacing:-1px;margin:22px 0 28px}aside nav{display:grid;gap:6px}aside nav a{padding:11px 12px;text-decoration:none;color:var(--muted);font-size:14px;font-weight:650;border-radius:7px}aside nav a.active{background:#e9f3ff;color:var(--blue);box-shadow:inset 3px 0 var(--blue)}.progress-box{margin-top:36px;border-top:1px solid var(--line);padding-top:24px;font-size:14px}.progress-box p{margin:3px 0}.progress-box small,.data{color:var(--muted);font-size:12px}.data{margin-top:20px}.data button{font-size:12px;margin-top:12px}.file-label input{max-width:100%;font-size:12px}progress{width:100%;height:7px;accent-color:var(--teal)}main{padding:42px clamp(22px,4vw,66px) 70px;min-height:calc(100vh - 180px);min-width:0}h1,h2,h3,h4{line-height:1.2}h1{font-size:clamp(32px,4vw,53px);letter-spacing:-1.8px;margin:12px 0 20px;max-width:850px}h2{font-size:25px;letter-spacing:-.6px;margin-top:0}h3{font-size:19px;margin:0 0 12px}p{margin:0 0 18px}.eyebrow{text-transform:uppercase;letter-spacing:1.5px;font-size:12px;font-weight:750;color:var(--teal)}.lead{color:var(--muted);max-width:690px;font-size:18px}.muted,small{color:var(--muted)}.topline,.section-head,.actions{display:flex;align-items:center;justify-content:space-between;gap:14px;flex-wrap:wrap}.actions{justify-content:flex-start;margin-top:20px}.pill{display:inline-block;background:#e1f3ed;color:#086354;font-size:12px;font-weight:650;border-radius:30px;padding:4px 10px}.hero-grid{display:grid;grid-template-columns:1.3fr 1fr;gap:28px;margin-top:30px}.feature{background:var(--ink);color:#fff;border-radius:16px;padding:30px;position:relative;overflow:hidden}.feature .eyebrow,.feature .muted{color:#a9d3fa}.feature h2{font-size:30px;max-width:450px}.feature p{color:#d3e2f2}.feature .primary{background:#fff;color:var(--ink);border-color:white}.feature .step-num{font-size:86px;font-weight:800;line-height:1;color:#4b7396;letter-spacing:-5px;margin-bottom:22px}.card{border:1px solid var(--line);border-radius:12px;background:#fff;padding:25px;min-width:0}.card p:last-child{margin-bottom:0}.card-link{text-decoration:none;color:inherit;display:block;transition:transform .15s}.card-link:hover{border-color:var(--blue);transform:translateY(-2px)}.grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px}.two{grid-template-columns:repeat(2,minmax(0,1fr))}.section{margin-top:36px}.section-head{margin-bottom:18px}.section-head h2{margin:0}.metric{font-size:32px;font-weight:800;color:var(--blue)}.callout{padding:20px 23px;background:#eaf6f2;border-left:4px solid var(--teal);border-radius:0 9px 9px 0;margin:22px 0}.callout.warning{background:#fff5df;border-color:#bc7800}.lesson-layout{display:grid;grid-template-columns:210px minmax(0,1fr);gap:28px}.lesson-menu{align-self:start;display:grid;gap:4px;max-height:80vh;overflow:auto;position:sticky;top:20px}.lesson-menu a{padding:8px 10px;text-decoration:none;font-size:14px;color:var(--muted);border-radius:6px}.lesson-menu a.active{background:var(--blue);color:white}.reading{max-width:790px}.reading h2{margin-top:30px}.reading p,.reading li{line-height:1.85}.reading li{margin-bottom:8px}.reading h1{font-size:39px}.reading .card h2{margin-top:0}.number{display:inline-grid;place-items:center;width:36px;height:36px;background:#e7f2fd;color:var(--blue);border-radius:9px;font-weight:750;margin-bottom:16px}label{display:block;font-size:14px;font-weight:650;margin-bottom:16px}label small{display:block;font-weight:400;margin:4px 0 7px}input:not([type=checkbox]):not([type=radio]):not([type=file]),textarea,select{width:100%;padding:11px 12px;border:1px solid #b8cadb;border-radius:7px;background:white;color:var(--ink);margin-top:6px;min-width:0}textarea{resize:vertical;min-height:105px;line-height:1.55}textarea.output{min-height:500px;font:14px/1.7 ui-monospace,SFMono-Regular,monospace;background:#f4f8fc}.studio{display:grid;grid-template-columns:1fr 1fr;gap:24px}.studio .card{align-self:start}.hint{font-size:14px;color:var(--muted);margin-top:8px}.feedback{border-radius:8px;padding:15px;background:#edf5ff;margin-top:15px}.feedback:empty{display:none}.choices{display:grid;gap:10px}.choices button{justify-content:flex-start;text-align:left;font-weight:500}.choices button.chosen{background:#e5f4ee;border-color:var(--teal)}details{margin:14px 0}summary{cursor:pointer;font-weight:650}details p{margin-top:12px}.check-row{display:flex;align-items:flex-start;gap:12px;padding:17px 0;border-bottom:1px solid var(--line);font-size:16px}.check-row input{width:20px;height:20px;flex-shrink:0;margin-top:5px;accent-color:var(--teal)}.check-row small{font-weight:400;display:block}.tabs{display:flex;gap:10px;flex-wrap:wrap;margin:24px 0}.tabs button.selected{background:var(--ink);color:white}.code{font:14px/1.7 ui-monospace,SFMono-Regular,monospace;white-space:pre-wrap;overflow-wrap:anywhere;background:#edf4fa;padding:18px;border-radius:8px}.flow{display:flex;gap:8px;flex-wrap:wrap;margin:20px 0}.flow span{padding:9px 13px;background:#eaf3fd;border-radius:6px;font-size:14px;font-weight:650}.project-step{display:grid;grid-template-columns:46px 1fr;gap:14px;margin:22px 0}.project-step h3{margin-top:6px}.resource a{font-weight:700}.resource p{margin-top:12px}.glossary{display:grid;grid-template-columns:1fr 1fr;gap:0 30px}.glossary dt{font-weight:750;margin-top:18px}.glossary dd{margin:5px 0;font-size:14px;color:var(--muted)}.score{font-size:32px;font-weight:800;color:var(--teal)}#toast{position:fixed;bottom:24px;left:50%;transform:translateX(-50%);background:var(--ink);color:white;padding:10px 20px;border-radius:9px;z-index:10;max-width:90vw;box-shadow:0 5px 25px #0002}#toast:empty{display:none}footer{padding:25px;text-align:center;border-top:1px solid var(--line);font-size:14px;background:white}footer small{font-size:12px}ul,ol{padding-left:23px}.example-preview{background:#eff6fc;border:1px solid var(--line);border-radius:8px;padding:15px}.demo-task{display:flex;align-items:center;gap:10px;margin-top:8px}.demo-task button{margin-left:auto}.demo-task input{width:18px;height:18px}input[type=checkbox]:checked+span{text-decoration:line-through}.print-only{display:none}@media(max-width:1100px){.layout{grid-template-columns:220px minmax(0,1fr)}aside{padding:25px 16px}.hero-grid,.studio,.lesson-layout{grid-template-columns:1fr}.lesson-menu{position:static;max-height:175px;background:white;border:1px solid var(--line);padding:10px;border-radius:8px}.grid{grid-template-columns:repeat(2,minmax(0,1fr))}}@media(max-width:700px){header{height:auto;min-height:80px;padding:15px 18px;flex-wrap:wrap}header nav{gap:12px}.brand small{font-size:9px}.layout{display:block}aside{padding:15px 18px;border-right:0;border-bottom:1px solid var(--line)}.edition,.course-title{display:none}.data{margin-top:10px}aside nav{display:flex;overflow:auto;gap:5px}aside nav a{white-space:nowrap}.progress-box{margin-top:12px;padding-top:10px}.progress-box small{display:none}.progress-box progress{max-width:150px;margin:0 12px}.progress-box p{display:inline;font-size:12px}main{padding:28px 18px 50px}.grid,.two,.hero-grid,.glossary{grid-template-columns:1fr}h1{letter-spacing:-1px}.reading h1{font-size:31px}.feature{padding:25px}.card{padding:20px}.lead{font-size:16px}.studio textarea.output{min-height:370px}.brand-icon{display:none}}@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important}}@media print{header,aside,footer,.actions,.tabs,#toast{display:none!important}.layout{display:block}main{padding:0}.card{break-inside:avoid}.print-only{display:block}body{background:white}}