:root{--ink:#192b3c;--muted:#526477;--teal:#176b72;--teal-dark:#105158;--line:#dce4ea;--paper:#f7f9fc;--sky:#e6f3f4;--purple:#6b59a1;--gold:#91611c;--red:#ac3742;--radius:14px;font-family:"Avenir Next","Segoe UI",Arial,sans-serif;color:var(--ink);background:var(--paper);font-synthesis:none}
*{box-sizing:border-box}body{margin:0}button,input,textarea,select{font:inherit}a{color:var(--teal);text-underline-offset:3px}button,a,input,textarea,select{ -webkit-tap-highlight-color:transparent}button{cursor:pointer}button:disabled{cursor:not-allowed;opacity:.55}a:focus-visible,button:focus-visible,input:focus-visible,textarea:focus-visible,select:focus-visible,summary:focus-visible{outline:3px solid #198a9a;outline-offset:4px}button{border:0}h1,h2,h3,h4,p{margin-top:0}h1{font-size:38px;line-height:1.2;letter-spacing:-1.2px;margin-bottom:16px}h2{font-size:23px;letter-spacing:-.5px;line-height:1.35;margin-bottom:12px}h3{font-size:18px;line-height:1.4;margin-bottom:8px}p,li{line-height:1.75}p{margin-bottom:18px}ul,ol{padding-left:24px}li{margin-bottom:7px}small,.muted{color:var(--muted)}code,pre,.editor{font-family:"SFMono-Regular",Consolas,"Liberation Mono",monospace}code{background:#edf1f6;border-radius:4px;padding:2px 5px;font-size:.9em}pre{white-space:pre-wrap;overflow-wrap:anywhere;line-height:1.65;font-size:13px;margin:0}.skip-link{position:fixed;top:-60px;left:10px;padding:12px;background:white;z-index:20}.skip-link:focus{top:8px}.sidebar{position:fixed;inset:0 auto 0 0;width:250px;background:white;border-right:1px solid var(--line);padding:35px 23px 23px;display:flex;flex-direction:column;z-index:5}.brand{display:flex;gap:12px;align-items:center;text-decoration:none;color:var(--ink);font-weight:750;font-size:23px;letter-spacing:-.8px;line-height:1.15;margin-bottom:44px}.brand-caption{display:block;font-size:10px;font-weight:500;color:var(--muted);letter-spacing:.15px;margin-top:8px}.brand-mark{position:relative;display:block;width:35px;height:35px;flex:none}.brand-mark i{position:absolute;background:var(--teal);width:10px;border-radius:3px;bottom:2px}.brand-mark i:nth-child(1){left:0;height:12px}.brand-mark i:nth-child(2){left:12px;height:23px}.brand-mark i:nth-child(3){left:24px;height:34px}.nav-item{display:flex;align-items:center;gap:13px;padding:13px 14px;margin:3px 0;text-decoration:none;color:var(--muted);border-radius:9px;font-size:14px;font-weight:550}.nav-item:hover{background:#f4f7f9}.nav-item.active{background:var(--sky);color:var(--teal);font-weight:700}.nav-icon{width:19px;height:19px;stroke:currentColor;fill:none;stroke-width:1.7;stroke-linecap:round;stroke-linejoin:round}.sidebar-path{margin-top:35px;border-top:1px solid var(--line);padding-top:24px}.small-label{font-size:12px;color:var(--muted);font-weight:600;margin-bottom:12px}.sidebar-path a{display:flex;align-items:center;gap:10px;font-size:12px;text-decoration:none;color:var(--muted);padding:9px 4px}.track-dot{width:7px;height:7px;border-radius:50%;display:inline-block;flex:none}.python{background:#28858a}.oop{background:var(--purple)}.dsa{background:#ae822f}.sidebar-bottom{margin-top:auto;padding-top:30px}.sidebar-bottom p{font-family:Georgia,serif;font-size:17px;line-height:1.5;color:#718290}.sidebar-bottom a{display:block;font-size:11px;text-decoration:none;margin-top:12px}.version{display:block;font-size:10px;color:#647587;margin-top:20px}.workspace{margin-left:250px}.topbar{height:80px;border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;padding:0 44px;background:#ffffffb8;gap:12px}.topbar #breadcrumb{font-size:13px;color:var(--muted)}.top-actions{display:flex;align-items:center;gap:18px}#sync-status{font-size:11px;color:var(--muted);max-width:220px}.avatar{display:grid;place-items:center;background:#dcecef;border:1px solid #c4dfe0;width:34px;height:34px;border-radius:50%;font-size:12px;font-weight:700;text-decoration:none}.mobile-toggle{display:none}.icon-button{background:transparent;color:var(--ink);font-size:20px;padding:8px}.workspace main{max-width:1320px;margin:auto;padding:44px;min-height:calc(100vh - 144px)}.welcome-line{font-size:13px;color:var(--teal);font-weight:600;margin-bottom:18px}.hero{display:grid;grid-template-columns:1.3fr 1fr;gap:35px;align-items:center;margin-bottom:38px}.hero h1{font:normal 48px/1.12 Georgia,serif;letter-spacing:-1.5px;max-width:510px}.hero p{font-size:15px;color:var(--muted);max-width:490px}.hero .hero-actions{display:flex;gap:12px;flex-wrap:wrap;align-items:center;margin-top:25px}.button{display:inline-flex;justify-content:center;align-items:center;gap:8px;background:var(--teal);color:white;padding:12px 19px;border-radius:8px;font-size:13px;font-weight:650;text-decoration:none;line-height:1.4;border:1px solid transparent;min-height:44px}.button:hover{background:var(--teal-dark)}.button.secondary{background:white;color:var(--ink);border-color:var(--line)}.button.secondary:hover{background:#eef4f7}.button.quiet{color:var(--teal);background:transparent;padding-left:0;padding-right:0}.button.small{padding:8px 12px;min-height:36px;font-size:12px}.concept-art{padding:34px 26px;border:1px solid #cfe1e3;border-radius:18px;background:linear-gradient(0deg,#edf5f6,#edf5f6);position:relative;min-height:232px}.art-top{display:flex;align-items:center;gap:8px;color:var(--teal);font-size:12px;margin-bottom:29px}.art-dot{height:7px;width:7px;background:var(--teal);border-radius:50%}.flow{display:flex;align-items:center;gap:10px}.flow-node{background:white;border:1px solid #c5dadd;border-radius:9px;padding:15px 10px;text-align:center;flex:1;box-shadow:0 3px 0 #d9e8ea}.flow-node span{display:block;font-size:21px;margin-bottom:10px}.flow-node strong{font-size:12px}.flow-arrow{color:#6e9a9e}.art-caption{font-size:11px!important;text-align:center;margin:22px 0 0!important;max-width:none!important}.journey-layout{display:grid;grid-template-columns:minmax(0,1fr) 275px;gap:28px}.section-title{display:flex;justify-content:space-between;align-items:baseline;gap:12px;margin-bottom:15px}.section-title h2{font-size:20px;margin:0}.section-title a{font-size:12px;text-decoration:none}.continue-box{border:1px solid #bcd8db;border-left:4px solid var(--teal);padding:23px;background:white;border-radius:12px;margin-bottom:32px;display:flex;align-items:center;justify-content:space-between;gap:18px}.continue-box h3{margin-top:8px}.continue-box p{font-size:13px;color:var(--muted);margin:0}.eyebrow{font-size:11px;color:var(--muted);font-weight:650}.track-row{display:flex;gap:18px;padding:23px 0;border-bottom:1px solid var(--line);text-decoration:none;color:var(--ink);align-items:flex-start}.track-number{width:42px;height:42px;border-radius:12px;display:grid;place-items:center;font-size:17px;font-weight:700;flex:none;background:#e6f3f4;color:var(--teal)}.track-row[data-track=oop] .track-number{color:var(--purple);background:#eeeaf7}.track-row[data-track=dsa] .track-number{color:var(--gold);background:#f7f0df}.track-main{flex:1}.track-main h3{font-size:16px;margin:0 0 5px}.track-main p{font-size:12px;color:var(--muted);margin:0 0 12px;line-height:1.6}.track-meta{font-size:11px;color:var(--muted);display:flex;justify-content:space-between;gap:12px}.progress-bar{height:5px;background:#e7edf1;border-radius:20px;overflow:hidden;margin:11px 0}.progress-fill{height:100%;background:var(--teal);border-radius:20px}.track-chevron{color:#687e8c;margin-top:10px}.side-panel{background:white;border:1px solid var(--line);border-radius:14px;padding:23px;margin-bottom:22px}.side-panel h3{font-size:15px}.side-panel p{font-size:12px;color:var(--muted)}.progress-circle{--pct:0;display:grid;place-items:center;margin:23px auto;background:conic-gradient(var(--teal) calc(var(--pct)*1%),#eaf0f3 0);width:118px;height:118px;border-radius:50%}.progress-circle>div{background:white;border-radius:50%;width:98px;height:98px;display:flex;align-items:center;justify-content:center;flex-direction:column}.progress-circle strong{font-size:27px;letter-spacing:-1px}.progress-circle span{font-size:10px;color:var(--muted)}.mini-stat{display:flex;justify-content:space-between;font-size:12px;padding:9px 0;border-bottom:1px solid #edf1f5}.mini-stat:last-child{border:0}.ritual{padding-left:19px;font-size:12px;color:var(--muted)}.ritual strong{color:var(--ink)}.page-intro{max-width:760px;margin-bottom:28px}.page-intro p{color:var(--muted);font-size:15px}.page-intro .back{display:inline-block;font-size:12px;margin-bottom:20px;text-decoration:none}.filters{display:flex;align-items:center;gap:10px;flex-wrap:wrap;margin-bottom:25px}.search{border:1px solid var(--line);border-radius:8px;padding:11px 13px;min-width:220px;flex:1;background:white;color:var(--ink)}select{border:1px solid var(--line);padding:11px;background:white;border-radius:8px;color:var(--ink)}.filter-chip{background:white;color:var(--muted);border:1px solid var(--line);border-radius:22px;padding:9px 15px;font-size:12px}.filter-chip.active{background:var(--teal);border-color:var(--teal);color:white}.lesson-list{border:1px solid var(--line);border-radius:14px;background:white;overflow:hidden}.lesson-row{padding:21px 24px;display:flex;gap:18px;align-items:center;text-decoration:none;color:var(--ink);border-bottom:1px solid var(--line)}.lesson-row:last-child{border:0}.lesson-row:hover{background:#f7fbfc}.lesson-index{font-size:13px;width:30px;color:var(--muted);flex:none}.lesson-row-body{flex:1;min-width:0}.lesson-row h3{font-size:15px;margin-bottom:3px}.lesson-row p{font-size:12px;color:var(--muted);margin:0}.badge{display:inline-block;font-size:10px;line-height:1.5;border-radius:20px;padding:4px 9px;background:#edf2f6;color:#526477;font-weight:600;white-space:nowrap}.badge.easy,.badge.done{background:#e5f3ed;color:#266547}.badge.medium{background:#fff2d9;color:#7b5414}.badge.complex{background:#eeeafa;color:#64478a}.lesson-meta{font-size:12px;color:var(--muted);display:flex;gap:13px;align-items:center;flex-wrap:wrap}.lesson-layout{display:grid;grid-template-columns:minmax(0,1fr) 240px;gap:28px}.lesson-body{background:white;border:1px solid var(--line);border-radius:14px;overflow:hidden}.lesson-tabs{display:flex;background:#f2f6f8;border-bottom:1px solid var(--line);gap:0}.lesson-tab{background:transparent;flex:1;padding:17px 10px;color:var(--muted);font-size:12px;line-height:1.4;border-bottom:3px solid transparent}.lesson-tab.active{color:var(--teal);border-bottom-color:var(--teal);background:white;font-weight:700}.lesson-content{padding:30px}.lesson-content>p{font-size:15px;line-height:1.85;max-width:72ch}.lesson-content h2{font-size:21px;margin-top:28px}.lesson-content h2:first-child{margin-top:0}.analogy{background:var(--sky);border-left:3px solid var(--teal);padding:23px;border-radius:0 10px 10px 0;margin:25px 0}.analogy p{font-size:14px;margin:0}.analogy h3{font-size:15px;color:var(--teal);margin-bottom:10px}.callout{padding:18px 20px;background:#f7f9fc;border:1px solid var(--line);border-radius:10px;margin:20px 0;font-size:13px}.callout p:last-child{margin-bottom:0}.callout.warning{background:#fff8e9;border-color:#eedfbb}.callout.success{background:#eaf6f0;border-color:#bfddcf;color:#245d44}.concept-steps{font-size:14px}.concept-steps li{margin:12px 0}.think-prompt{border:1px dashed #abc8cc;padding:23px;border-radius:10px;margin:24px 0}.think-prompt p{font-size:14px}.think-prompt summary{font-size:12px;color:var(--teal);cursor:pointer;font-weight:650}.think-prompt details p{margin-top:15px;font-size:13px;color:var(--muted)}.end-actions{display:flex;justify-content:space-between;gap:14px;align-items:center;margin-top:28px;flex-wrap:wrap}.resource-link{display:block;text-decoration:none;border-top:1px solid var(--line);padding:14px 0}.resource-link strong{font-size:12px}.resource-link p{font-size:11px;line-height:1.6;margin:6px 0 0;color:var(--muted)}.resource-type{font-size:10px;display:block;color:var(--muted);margin-bottom:5px}.note-area{width:100%;min-height:120px;border:1px solid var(--line);border-radius:8px;resize:vertical;padding:12px;font-size:12px;line-height:1.6}.save-note{margin-top:10px;width:100%}.quiz-question{border:0;border-bottom:1px solid var(--line);padding:0 0 24px;margin:0 0 26px;width:100%;min-width:0}.quiz-question legend{font-weight:650;font-size:15px;line-height:1.65;margin-bottom:15px;float:left;width:100%}.quiz-options{clear:both;display:grid;gap:9px}.quiz-option{display:flex;align-items:flex-start;gap:10px;border:1px solid var(--line);padding:13px;border-radius:8px;cursor:pointer;font-size:13px;line-height:1.6}.quiz-option input{margin-top:4px;accent-color:var(--teal)}.quiz-option:has(input:checked){background:var(--sky);border-color:var(--teal)}.quiz-feedback{margin-top:13px;font-size:13px;padding:12px;border-radius:8px}.quiz-feedback.correct{background:#edf7f1;color:#246448}.quiz-feedback.incorrect{background:#fff0ee;color:#933d35}.quiz-feedback p{margin:4px 0 0}.code-wrap{background:#1a2d3c;border-radius:10px;overflow:hidden;margin:18px 0}.code-toolbar{background:#233b4e;padding:11px 16px;display:flex;justify-content:space-between;gap:12px;color:#d9e8f0;font-size:11px;align-items:center}.code-wrap pre{color:#e2edf4;padding:19px}.editor{display:block;width:100%;min-height:265px;resize:vertical;background:#1a2d3c;color:#e3f1f5;border:0;line-height:1.7;font-size:13px;padding:18px;tab-size:4;outline-offset:-3px!important}.exercise-heading{display:flex;align-items:center;gap:12px;margin:20px 0 13px}.exercise-heading h3{margin:0}.exercise-select{width:100%;margin:12px 0}.exercise-prompt{white-space:pre-line;font-size:14px}.sample-list{font-size:12px;background:#f4f7fa;border-radius:8px;padding:14px;list-style:none}.sample-list li{margin-bottom:5px;font-family:Consolas,monospace;overflow-wrap:anywhere}.hint-box{font-size:13px;padding:14px 0}.hint-box summary{color:var(--teal);cursor:pointer;font-weight:650}.hint-box p,.hint-box pre{margin-top:14px}.run-actions{display:flex;gap:10px;align-items:center;flex-wrap:wrap}.runtime-status{font-size:11px;color:var(--muted)}.test-results{margin-top:18px}.test-row{padding:10px 14px;background:#f2f7f5;border-bottom:1px solid #dcebe4;font-size:12px;line-height:1.6}.test-row.fail{background:#fff2f0;color:#973f38}.console{background:#f1f4f8;border-radius:8px;padding:17px;font-size:12px;margin-top:14px;white-space:pre-wrap;overflow-wrap:anywhere;max-height:350px;overflow:auto}.error-text{color:var(--red)}.practice-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:17px}.practice-card{background:white;border:1px solid var(--line);border-radius:12px;padding:23px;display:flex;flex-direction:column}.practice-card h3{margin:13px 0 9px;font-size:16px}.practice-card p{font-size:12px;color:var(--muted);flex:1}.practice-card .card-bottom{display:flex;align-items:center;justify-content:space-between;gap:10px;margin-top:9px}.empty-state{background:white;border:1px dashed var(--line);border-radius:12px;padding:40px;text-align:center;color:var(--muted)}.empty-state h2{color:var(--ink)}.video-channel{padding:24px 0;border-bottom:1px solid var(--line);display:grid;grid-template-columns:50px 1fr auto;gap:20px;align-items:center}.channel-icon{display:grid;place-items:center;width:46px;height:46px;background:#e8f1f5;border-radius:12px;color:var(--teal);font-size:13px;font-weight:700}.video-channel p{font-size:13px;color:var(--muted);margin-bottom:4px}.video-channel h3{font-size:17px;margin-bottom:6px}.video-library{margin-top:35px}.video-library .lesson-row{align-items:flex-start}.notebook-card{background:white;border:1px solid var(--line);border-radius:12px;padding:24px;margin-bottom:16px}.notebook-card p{white-space:pre-wrap;font-size:14px;overflow-wrap:anywhere}.notebook-card h3{font-size:16px}.guide-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:24px}.guide-panel{background:white;padding:28px;border-radius:12px;border:1px solid var(--line)}.guide-panel li,.guide-panel p{font-size:14px}.account-panel{background:white;border:1px solid var(--line);border-radius:14px;padding:30px;max-width:800px}.account-panel p{font-size:14px}.account-controls{display:flex;gap:12px;flex-wrap:wrap;margin:23px 0}.danger{color:var(--red)!important;border-color:#e1b5b9!important}.site-footer{display:flex;gap:20px;flex-wrap:wrap;font-size:10px;color:var(--muted);padding:24px 44px;border-top:1px solid var(--line)}.site-footer span{margin-right:auto}.site-footer a{text-decoration:none}.toast{position:fixed;bottom:24px;left:calc(50% + 100px);transform:translateX(-50%);z-index:30;background:var(--ink);color:white;padding:13px 20px;border-radius:9px;max-width:calc(100vw - 32px);font-size:13px;box-shadow:0 6px 24px #192b3c20}.loading-state{padding:60px 20px;text-align:center}.loading-state h1{font-size:25px}.loading-dot{display:inline-block;width:12px;height:12px;background:var(--teal);border-radius:50%;margin-bottom:25px;animation:pulse 1.3s infinite}.lesson-progress-line{height:4px;background:var(--line);border-radius:4px;margin:15px 0}.lesson-progress-line span{display:block;height:100%;background:var(--teal);border-radius:4px}.sr-only{position:absolute;width:1px;height:1px;padding:0;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.step-list{list-style:none;padding:0;font-size:12px;color:var(--muted)}.step-list li{display:flex;gap:9px;margin:12px 0}.step-list .checked{color:var(--teal);font-weight:700}.plain-list{list-style:none;padding:0}.page-count{font-size:12px;color:var(--muted);margin-bottom:15px}.status-banner{padding:12px 17px;background:#fff5df;border:1px solid #ecd7a6;border-radius:8px;font-size:12px;margin-bottom:25px}.reference-note{font-size:12px;color:var(--muted);border-top:1px solid var(--line);padding-top:15px;margin-top:25px}
@keyframes pulse{50%{opacity:.35}}@media(min-width:1600px){.workspace main{padding-top:55px}.hero h1{font-size:55px}}@media(max-width:1180px){.sidebar{width:220px;padding-left:17px;padding-right:17px}.workspace{margin-left:220px}.workspace main{padding:30px}.topbar{padding:0 30px}.journey-layout{grid-template-columns:minmax(0,1fr) 240px;gap:20px}.hero h1{font-size:41px}.hero{gap:23px}.concept-art{padding:25px 17px}.lesson-layout{grid-template-columns:minmax(0,1fr) 215px;gap:18px}.lesson-content{padding:24px}.flow{gap:5px}.flow-node{padding:14px 7px}.flow-node strong{font-size:10px}.continue-box{flex-wrap:wrap}}@media(max-width:980px){.hero{grid-template-columns:1fr}.concept-art{display:none}.journey-layout{grid-template-columns:1fr}.dashboard-side{display:grid;grid-template-columns:1fr 1fr;gap:20px}.lesson-layout{grid-template-columns:1fr}.lesson-aside{display:grid;grid-template-columns:1fr 1fr;gap:18px}.practice-grid{grid-template-columns:1fr}.guide-grid{grid-template-columns:1fr}.lesson-row .lesson-time{display:none}.hero h1{max-width:100%}}@media(max-width:720px){.sidebar{transform:translateX(-100%);width:255px;box-shadow:15px 0 35px #192b3c22;transition:transform .18s}.sidebar.open{transform:translateX(0)}.workspace{margin-left:0}.mobile-toggle{display:block}.topbar{height:67px;padding:0 18px}.topbar #breadcrumb{flex:1;font-size:12px}.top-actions{gap:10px}#sync-status{max-width:120px;font-size:9px}.workspace main{padding:27px 19px}.hero{margin-bottom:27px}.hero h1{font-size:42px}.hero p{font-size:14px}.journey-layout{gap:25px}.dashboard-side,.lesson-aside{display:block}.continue-box{padding:19px}.track-row{gap:13px}.track-main p{font-size:12px}.track-number{width:35px;height:35px}.page-intro h1{font-size:29px}.page-intro p{font-size:14px}.lesson-row{padding:18px 15px;gap:10px}.lesson-row h3{font-size:14px}.lesson-row p{font-size:11px}.lesson-index{width:24px}.lesson-row>.badge{max-width:78px;white-space:normal;text-align:center}.lesson-content{padding:22px 18px}.lesson-content>p{font-size:14px}.lesson-tab{font-size:11px;padding:15px 6px}.video-channel{grid-template-columns:42px 1fr;gap:15px}.video-channel>.button{grid-column:2;justify-self:start}.search{width:100%;min-width:0;flex-basis:100%}.filters select{flex:1;min-width:0}.site-footer{padding:21px 19px;gap:12px}.site-footer span{flex-basis:100%}.toast{left:50%}.account-panel{padding:23px 18px}.code-wrap pre{font-size:11px;padding:16px}.editor{font-size:12px}.lesson-meta{font-size:11px}}@media(prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important;scroll-behavior:auto!important}}

main:focus{outline:none}

/* The roadmap stays compact as the curriculum grows. */
.sidebar{overflow-y:auto}.brand{flex-shrink:0;margin-bottom:26px}.sidebar-path{margin-top:22px;padding-top:18px}.sidebar-bottom{padding-top:22px}.stage-dot{display:grid;place-items:center;width:21px;height:21px;flex:none;background:var(--sky);color:var(--teal);border-radius:6px;font-size:10px;font-weight:700}.stage-block{background:#fff;border:1px solid var(--line);border-radius:12px;padding:0 20px;margin-bottom:14px}.stage-block>summary{cursor:pointer;padding:19px 0;list-style:none;position:relative;padding-right:25px}.stage-block>summary::-webkit-details-marker{display:none}.stage-block>summary:after{content:'+';position:absolute;right:0;top:30px;font-size:20px;color:var(--teal)}.stage-block[open]>summary:after{content:'−'}.stage-block>summary strong,.stage-block>summary span{display:block}.stage-block>summary strong{font-size:17px;margin:7px 0}.stage-block>summary span:last-child{font-size:12px;line-height:1.6;color:var(--muted)}.stage-block .track-row:last-child{border:0}.stage-block .track-row:first-of-type{border-top:1px solid var(--line)}.case-study{padding:22px;background:#f3f7fb;border:1px solid var(--line);border-radius:12px;margin:25px 0}.case-study dt{font-size:13px;font-weight:700;margin-top:15px}.case-study dd{margin:7px 0;font-size:14px;line-height:1.8}.case-study>a{font-size:12px}.reasoning-editor{min-height:150px;font-size:14px;margin:12px 0 20px}.project-label{display:block;margin-top:24px}.project-answer{min-height:200px;font-size:14px}.exercise-heading{flex-wrap:wrap}.exercise-heading h3{flex:1;min-width:140px}.lesson-layout,.lesson-body,.code-wrap,.stage-block{min-width:0}select{max-width:100%}

/* Product design is a guided notebook with a single request journey. */
.design-invitation{display:flex;align-items:center;gap:24px;justify-content:space-between;padding:23px 0;margin-bottom:26px;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.design-invitation h2{font-size:19px}.design-invitation p{margin:0;font-size:14px}.design-invitation .button{flex-shrink:0}
.design-start{border-left:3px solid var(--teal);padding:4px 0 4px 22px;margin:0 0 30px}.design-start h2{font-size:20px}.design-start p{font-size:14px;max-width:76ch}.design-start p:last-child{margin-bottom:0}.design-product{margin-bottom:30px}.design-product>h2{font-size:23px;margin:20px 0 14px}
.design-lab{margin:32px 0;border-top:2px solid var(--teal);padding-top:25px;overflow-wrap:anywhere}.design-lab>header h2{margin-top:15px}.design-lab p,.design-lab li,.design-lab dd{font-size:14px;line-height:1.8;max-width:72ch}.design-lab>h3{margin-top:26px}.design-lab h4{font-size:14px;margin:20px 0 8px}.design-lab .reference-note{font-size:12px}
.design-flow{padding:0;list-style:none;margin:22px 0 30px}.design-flow>li{display:flex;gap:14px;position:relative;margin:0;padding-bottom:20px}.design-flow>li:not(:last-child):before{content:'';position:absolute;left:15px;top:32px;bottom:0;border-left:1px solid var(--line)}.design-flow-number{display:grid;place-items:center;flex:0 0 32px;height:32px;border:1px solid var(--line);background:var(--sky);color:var(--teal);border-radius:50%;font-size:12px;font-weight:700}.design-flow>li>div{padding-top:3px;min-width:0}.design-flow p{margin:5px 0 0}.design-flow>li:last-child{padding-bottom:0}
.design-detail{border-top:1px solid var(--line)}.design-detail>summary{cursor:pointer;padding:17px 0;font-size:15px;font-weight:650;line-height:1.6}.design-detail>div{padding:0 0 14px 18px}.design-detail>div>p:first-of-type{margin-top:14px}.design-detail .badge{margin-top:5px}.design-calculation{background:var(--paper);border-left:3px solid var(--line);padding:16px;margin:15px 0;white-space:pre-wrap;overflow-wrap:anywhere}.design-definitions{margin:20px 0}.design-definitions dt{font-weight:650;margin:18px 0 8px}.design-definitions dd{margin:0}.design-definitions code{white-space:pre-wrap;overflow-wrap:anywhere}.design-definitions dd p{margin-top:9px}
.design-evidence{margin-top:22px;padding:20px;background:var(--paper);border-radius:8px}.design-evidence h3{font-size:17px}.design-evidence p:last-child{margin-bottom:0}
@media(max-width:700px){.design-invitation{align-items:flex-start;flex-direction:column;gap:17px}.design-start{padding-left:16px}.design-detail>div{padding-left:0}.design-evidence{padding:16px}.design-flow>li{gap:11px}}

/* Responsive SVG lessons: inspect a small concrete example before more prose. */
.concept-visual{margin:27px 0 30px;border:1px solid var(--line);border-radius:12px;background:var(--paper);overflow:hidden}.visual-heading{padding:21px 23px 0}.visual-heading h2{margin-top:13px;font-size:21px}.visual-heading p{font-size:14px;margin-bottom:10px}.visual-canvas{max-width:430px;margin:0 auto;padding:0 12px}.visual-canvas svg{display:block;width:100%;height:auto}.visual-step{padding:18px 23px 0;border-top:1px solid var(--line);background:#fff}.visual-step h3{margin-top:8px;font-size:17px}.visual-step p{font-size:14px;margin-bottom:0;padding-bottom:17px;min-height:74px}.visual-controls{display:flex;align-items:center;flex-wrap:wrap;gap:10px;padding:0 23px 19px;background:#fff}.visual-controls>a{font-size:12px;margin-left:auto}.visual-text{border-top:1px solid var(--line);padding:13px 23px;font-size:13px}.visual-text>summary{cursor:pointer;color:var(--muted)}.visual-text li{font-size:13px}.visual-text ul,.visual-text ol{margin-bottom:8px}
@media(max-width:600px){.visual-heading{padding:17px 14px 0}.visual-canvas{padding:0 4px}.visual-step{padding:16px 14px 0}.visual-controls{padding:0 14px 17px;gap:9px}.visual-controls>a{margin:2px 0 0;width:100%}.visual-text{padding:13px 14px}.visual-controls .button{padding:10px 12px}.visual-heading h2{font-size:19px}}

/* A focused learning workspace: one next task and four main destinations. */
[hidden]{display:none!important}
.sidebar{overflow-y:auto;overscroll-behavior:contain;padding-top:26px;padding-bottom:max(23px,env(safe-area-inset-bottom))}
.brand{margin-bottom:27px}.nav-item{min-height:46px}.nav-item span{min-width:0}
.more-navigation{margin-top:13px;border-top:1px solid var(--line);padding-top:9px}
.more-navigation>summary{padding:13px 14px;min-height:46px;cursor:pointer;font-size:13px;color:var(--muted);font-weight:650}
.more-navigation .nav-item{font-size:13px;padding-top:10px;padding-bottom:10px}
.sidebar-path{margin-top:22px;padding-top:20px}.sidebar-guidance{font-size:12px;color:var(--muted);line-height:1.7}
.sidebar-bottom{padding-top:22px}.sidebar-bottom>p,.version{display:none}.sidebar-bottom>a{min-height:40px;font-size:12px;display:flex;align-items:center}.sidebar-bottom .button{margin-top:12px;width:100%;min-height:44px}
.signed-in-actions{display:flex;align-items:center;gap:12px}.signed-in-actions>a,.signout-button{font-size:13px;font-weight:650;text-decoration:none;min-height:44px;display:inline-flex;align-items:center;justify-content:center}.signout-button{background:white;color:var(--teal);border:1px solid var(--line);padding:0 13px;border-radius:8px;white-space:nowrap}
#account-link{display:none}.topbar{gap:14px}.top-actions{gap:14px;min-width:0}#sync-status{max-width:140px}.topbar #breadcrumb a{text-decoration:none;color:inherit}
.close-navigation,.navigation-backdrop{display:none}
.today-intro{max-width:720px}.today-intro h1{font-size:36px;margin-bottom:12px}.today-intro p{color:var(--muted);font-size:15px}
.focus-choices{padding:0;border:0;margin:24px 0;display:flex;gap:9px;flex-wrap:wrap}.focus-choices legend{padding:0;margin-bottom:10px;color:var(--muted);font-size:13px}.focus-choice{font-size:13px;background:white;border:1px solid var(--line);border-radius:8px;padding:10px 14px;min-height:44px;color:var(--ink)}.focus-choice[aria-pressed=true]{color:var(--teal);background:var(--sky);border-color:var(--teal);font-weight:650}
.today-task{max-width:800px;border-top:3px solid var(--teal);padding:25px 28px;background:white;border-radius:0 0 12px 12px;box-shadow:0 2px 6px #192b3c09}.today-task-heading{display:flex;justify-content:space-between;flex-wrap:wrap;gap:6px;color:var(--muted);font-size:12px;margin-bottom:16px}.today-task h2{font-size:27px;margin-bottom:16px}.today-task>p{max-width:72ch;font-size:14px}.today-task .today-primary{min-height:46px;display:inline-flex;align-items:center;margin-top:20px}.today-next-detail{color:var(--muted);font-size:12px!important;margin:14px 0 0}
.quick-check{border:0;padding:0;margin:20px 0 0;display:grid;grid-template-columns:1fr 1fr;gap:9px}.quick-check legend{font-size:15px;font-weight:650;margin-bottom:13px;line-height:1.6;max-width:100%;padding:0}.quick-option{text-align:left;border:1px solid var(--line);background:var(--paper);border-radius:8px;color:var(--ink);font-size:13px;line-height:1.6;padding:11px 14px;min-height:48px}.quick-option[aria-pressed=true]{background:var(--sky);border-color:var(--teal)}.quick-feedback{font-size:13px;line-height:1.7;margin-top:15px;min-height:23px}.quick-feedback p{margin:6px 0}.quick-feedback small{font-size:12px}.quick-feedback>span{color:var(--muted)}
.today-footer{font-size:13px;color:var(--muted);max-width:800px;padding-top:24px;display:flex;gap:12px 22px;flex-wrap:wrap;align-items:center}.today-footer p{width:100%;margin:0}.today-footer p>span{padding:0 5px}.today-footer a{display:inline-flex;align-items:center;min-height:44px}.today-footer p>a{margin-left:10px}.topic-access{display:block;color:var(--muted);font-size:11px;margin-top:8px}
@media(max-width:1000px){.topbar #sync-status{max-width:105px;font-size:10px}.topbar{padding-left:24px;padding-right:24px}.signed-in-actions{gap:8px}}
@media(max-width:720px){
 .navigation-open{overflow:hidden}.navigation-backdrop:not([hidden]){display:block;position:fixed;inset:0;z-index:20;background:#10263070;cursor:pointer}.sidebar{z-index:21;width:min(310px,calc(100vw - 36px));padding-top:max(17px,env(safe-area-inset-top));padding-left:21px;padding-right:21px;visibility:hidden;max-height:100dvh}.sidebar.open{visibility:visible}.close-navigation{display:flex;align-items:center;justify-content:space-between;min-height:44px;background:transparent;color:var(--muted);font-size:13px;width:100%;margin-bottom:15px}.close-navigation>span{font-size:25px}.sidebar .brand{margin-bottom:22px}.sidebar-bottom{margin-top:18px}
 .topbar{min-height:67px;height:auto;padding:9px max(16px,env(safe-area-inset-right)) 9px max(16px,env(safe-area-inset-left));gap:9px;flex-wrap:wrap}.mobile-toggle{height:44px;width:44px;flex:none}.topbar #breadcrumb{font-size:12px;min-width:0}.top-actions{gap:5px}.signed-in-actions{gap:9px}.signed-in-actions>a,.signout-button{font-size:12px}.signout-button{padding:0 10px}.topbar #sync-status{position:absolute;top:auto;clip:rect(0,0,0,0);clip-path:inset(50%);height:1px;width:1px;overflow:hidden;white-space:nowrap}
 .workspace main{padding:25px max(17px,env(safe-area-inset-right)) 35px max(17px,env(safe-area-inset-left))}.today-intro h1{font-size:30px}.today-intro p{font-size:14px}.focus-choices{gap:8px;margin:21px 0}.focus-choice{font-size:12px;padding:10px 11px;flex:1 1 45%}.focus-choice:last-child{flex-basis:100%}.today-task{padding:21px 17px}.today-task h2{font-size:23px}.quick-check{grid-template-columns:1fr}.today-task .today-primary{width:100%;justify-content:center}.today-footer p>a{margin-left:0;display:flex}.today-footer{gap:5px 20px}.button,summary,select{min-height:44px}input:not([type=checkbox]):not([type=radio]),textarea,select{font-size:16px}
 .lesson-tabs{flex-wrap:wrap}.lesson-tab{min-width:30%;min-height:50px}.lesson-row{min-width:0}.lesson-row-body,.account-auth-layout,.account-form-panel,.account-plan{min-width:0}.site-footer{padding-bottom:max(21px,env(safe-area-inset-bottom))}
}
@media(max-width:360px){.topbar{gap:6px}.topbar #breadcrumb{font-size:11px}.signed-in-actions{gap:5px}.signout-button{padding:0 8px}.signed-in-actions>a{font-size:11px}.today-task-heading{font-size:11px}}
.curriculum-coverage{font-size:12px;color:var(--muted);max-width:82ch;padding:13px 0 13px 16px;border-left:3px solid var(--line);margin:0 0 24px;line-height:1.7}