@import url('https://fonts.googleapis.com/css2?family=DM+Sans:wght@400;500;600;700&family=Space+Grotesk:wght@400;500;600;700&display=swap');
:root{font-family:'DM Sans',sans-serif;color:#202737;background:#f6f7f9;font-synthesis:none;--ink:#171d2a;--muted:#737986;--line:#e4e7ec;--lime:#dafa80;--green:#346c40}*{box-sizing:border-box}body{margin:0}button,a,select,input{font:inherit}button,a,select{touch-action:manipulation}button{cursor:pointer}button{border:0;background:none;color:inherit}button:disabled{cursor:default;opacity:.4}button:focus-visible,a:focus-visible,select:focus-visible,input:focus-visible{outline:3px solid #6784e3;outline-offset:4px}a{color:inherit}svg{display:block}h1,h2,h3,p{margin:0}h1,h2,h3,.brand,.number{font-family:'Space Grotesk',sans-serif}h1{font-size:36px;letter-spacing:-1.6px;font-weight:600}h2{font-size:26px;letter-spacing:-.8px}h3{font-size:18px}p{line-height:1.65}header{height:82px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line);padding:0 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30px));color:var(--ink);box-shadow:0 30px 100px #10182730;background:#fff;max-height:90vh}dialog::backdrop{background:#11182785;backdrop-filter:blur(4px)}.modal-head{padding:19px 23px;display:flex;justify-content:space-between;border-bottom:1px solid var(--line);align-items:center;font-size:13px}.modal-head button{font-size:25px;width:32px;height:32px}.modal-body{padding:22px}.modal-body .workspace{border-radius:10px}.modal-body .cube-pane{min-height:400px}.modal-bottom{padding:0 23px 22px;font-size:12px;color:#7f8793}.notation-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px;margin-top:20px}.notation-item{background:#f4f6f8;border-radius:7px;padding:14px;display:flex;gap:15px;align-items:center;font-size:14px}.notation-item b{font-family:'Space Grotesk';font-size:23px;min-width:42px}.modal-body>p{font-size:14px;color:#748090;margin:10px 0}.case-choices{display:flex;gap:7px;flex-wrap:wrap;margin-bottom:20px}.case-choices button{padding:7px 10px;border:1px solid var(--line);border-radius:6px;font-size:12px}.case-choices button.active{background:#eaf1dd;border-color:#cbdba8}.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}.kbd{border:1px solid #d3d9e1;border-radius:3px;padding:2px 5px;font-size:11px} @media(min-width:1500px){.main{padding:44px 60px}.cube-pane{min-height:480px}.cube-stage svg{width:390px}}@media(max-width:1150px){header{padding:0 24px}.layout{grid-template-columns:225px minmax(0,1fr)}aside{padding:28px 14px}.main{padding:30px 25px}.lesson-pane{padding:23px 20px}.steps{gap:5px}.step{padding:10px 7px}.step strong{font-size:11px}.algorithm-grid{grid-template-columns:repeat(3,minmax(0,1fr))}.quick-card{padding:13px;gap:8px}.quick-card svg{width:45px}.btn{padding:11px 13px}.controls{gap:5px}.cube-pane{padding:20px;min-height:440px}.topnav{gap:23px}}@media(max-width:900px){.layout{grid-template-columns:1fr}aside{padding:20px 25px 0;border:0;background:transparent}.level-list{grid-template-columns:repeat(4,1fr);gap:6px;margin:0}aside>.eyebrow,.aside-help{display:none}.level{padding:10px 7px;background:#fff;border:1px solid var(--line)}.level strong{font-size:12px}.level small{font-size:10px}.level .level-icon{display:none}.main{padding-top:25px}.workspace{grid-template-columns:1fr 1.05fr}.heading h1{font-size:30px}.modal-body .workspace{grid-template-columns:1fr 1fr}.modal-body{padding:14px}.modal-body .lesson-pane{padding:20px 16px}.modal-body .cube-pane{padding:12px}}@media(max-width:650px){header{height:auto;min-height:75px;padding:16px 18px;flex-wrap:wrap;gap:15px}.brand{font-size:25px}.topnav{order:3;width:100%;height:35px;gap:0;justify-content:space-between}.topnav button{font-size:12px}.notation{padding:8px 10px;font-size:12px}.layout{min-height:calc(100vh - 125px)}aside{padding:18px 14px 0}.level strong{font-size:10px}.level small{display:none}.level{padding:12px 6px;justify-content:center;border-radius:6px}.main{padding:24px 14px}.heading{align-items:flex-start;margin-bottom:22px}.heading h1{font-size:29px}.heading p{font-size:12px;max-width:280px}.path-label{display:none}.steps{overflow-x:auto;padding-bottom:7px;gap:6px}.step{min-width:95px;padding:10px}.step strong{font-size:11px}.workspace,.modal-body .workspace{grid-template-columns:1fr}.cube-pane{min-height:300px;border-right:0;border-bottom:1px solid var(--line);padding:17px}.cube-stage{min-height:210px}.cube-stage svg{width:260px}.cube-view-buttons{margin-top:8px}.lesson-pane{padding:24px 21px}.lesson-pane h2{font-size:25px}.lesson-desc{font-size:14px}.below{align-items:flex-start}.tip{font-size:12px;max-width:58%}.below .btn{font-size:12px;padding:10px}.quick-cards{grid-template-columns:1fr}.quick-card{padding:12px 18px;gap:15px}.quick-card svg{width:45px}.quick-card strong{font-size:13px}.quick-card small{font-size:12px}.section-top span{font-size:11px}.algorithm-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:10px}.algorithm-card{padding:13px}.algorithm-card .card-title{font-size:14px}.algorithm-card svg{height:105px}.filters{width:100%}.filters input{min-width:0;flex:1;width:40%}.filters select{max-width:48%}.library-toolbar>.btn{padding:11px}.flash-top{flex-wrap:wrap}.flash-top select{max-width:150px}.flash-status{font-size:12px}.flash-actions .btn{padding:10px;font-size:12px}.modal-body .cube-pane{min-height:285px}.modal-body .cube-stage{min-height:200px}.modal-body .cube-stage svg{width:220px}.notation-grid{grid-template-columns:1fr}.foot{font-size:10px}.lesson-footer select{font-size:12px}.modal-head{padding:13px 18px}.flash-top+.btn{font-size:12px}.heading:has(.flash-top){flex-wrap:wrap}}@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important}}
.guide{font-size:13px;line-height:1.7;margin:-4px 0 18px;color:#647080}.guide summary{cursor:pointer;color:#424e61}.guide p{padding-top:8px}.case-choices{max-height:130px;overflow-y:auto;padding:2px}.controls .btn{font-size:12px}.cube-caption{min-height:18px}.topnav button:hover{color:#171d2a}.step:hover:not(.active){border-color:#99a2ae}.level:hover:not(.active){background:#f0f2f5}.algorithm-card:active{transform:translateY(0)}.flash-actions{flex-shrink:0}dialog .tip{font-size:12px}.lesson-footer>span{line-height:1.5;min-width:0}.lesson-footer label{flex-shrink:0}button.brand{padding:0}.btn:disabled{opacity:.38}.algorithm-card svg{pointer-events:none}.quick-card svg{pointer-events:none}@media(max-width:450px){.flash-actions{flex-direction:column}.controls .btn{padding:10px;font-size:11px}.controls .btn.icon{width:36px}.lesson-footer{font-size:11px}.lesson-footer select{font-size:11px}.lesson-pane{padding:22px 16px}.case-choices{max-height:110px}}

.lesson-desc{font-size:16px}.hold{font-size:14px}.tip{font-size:14px}.step strong{font-size:13px}.level strong{font-size:14px}.quick-card strong{font-size:14px}.btn{font-size:14px}.controls .btn{font-size:13px}.heading p{font-size:15px}.algorithm-card p{font-size:13px}.algorithm-card .card-title span{font-size:12px}.main{margin:0 auto}.lesson-pane{min-width:0}.workspace{min-width:0}.controls{flex-wrap:wrap}.lesson-footer{flex-wrap:wrap}@media(max-width:1150px){.step strong{font-size:12px}.level strong{font-size:13px}}@media(max-width:650px){.level strong{font-size:10px}.heading p{font-size:14px}.step strong{font-size:12px}.tip{font-size:13px}.controls .btn{font-size:12px}.controls{flex-wrap:nowrap}.lesson-desc{font-size:16px}}

/* Pair-building lessons and the beginner cross progression. */
.pair-intro{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px;margin:0 0 12px}.pair-intro>div{background:white;border:1px solid var(--line);border-radius:9px;padding:16px}.pair-intro strong{font-size:14px}.pair-intro p{font-size:14px;color:#687486;margin-top:7px}.pair-note{font-size:14px;color:#677485;margin:0 0 18px}.pair-note .text-btn{font-size:14px}.pair-phases{margin:0 0 20px;padding:13px;background:#f0f5e7;border:1px solid #dce5ce;border-radius:8px}.pair-phases nav{display:flex;flex-wrap:wrap;gap:5px;margin-bottom:10px}.pair-phases button{border:1px solid #cbd8b7;border-radius:5px;padding:6px 9px;font-size:12px}.pair-phases button.active{background:#253621;color:white;border-color:#253621}.pair-phases p{font-size:14px;color:#41503e;line-height:1.65}.pair-phases small{display:block;font-size:12px;color:#697b5c;margin-top:8px}.cross-follow{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:14px 16px;background:#eaf0df;border-radius:8px;margin-top:15px;font-size:14px;color:#526241}.segmented{flex-wrap:wrap}@media(max-width:650px){.pair-intro{grid-template-columns:1fr;gap:7px}.pair-intro>div{padding:12px 14px}.pair-intro p{margin-top:4px}.cross-follow{align-items:flex-start;flex-direction:column}.library-toolbar>.segmented{width:100%}.segmented button{padding:8px 12px}}