:root{--bg: #f7f7fb;--surface: #ffffff;--surface-2: #f1f2f8;--text: #171a2b;--muted: #5d6275;--line: #e2e4ee;--accent: #4f46e5;--accent-ink: #ffffff;--accent-soft: #eef0ff;--good: #0f7b53;--good-soft: #e6f6ef;--bad: #b42318;--bad-soft: #fdecea;--warn-soft: #fff7e6;--warn-line: #f5d38b;--code-bg: #0f1222;--code-ink: #e7e9f5;--radius: 14px;--shadow: 0 1px 2px rgb(16 18 35 / 6%), 0 8px 24px rgb(16 18 35 / 6%);--font: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;--mono: ui-monospace, SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;color-scheme:light}[data-theme=dark]{--bg: #0e1020;--surface: #161a2e;--surface-2: #1d2238;--text: #eceef8;--muted: #a3a8c0;--line: #2b3150;--accent: #8b85ff;--accent-ink: #0e1020;--accent-soft: #232650;--good: #4ade9c;--good-soft: #143528;--bad: #ff8a80;--bad-soft: #3b1c1c;--warn-soft: #33290f;--warn-line: #6b5520;--code-bg: #0a0c18;--shadow: 0 1px 2px rgb(0 0 0 / 30%), 0 8px 24px rgb(0 0 0 / 25%);color-scheme:dark}*{box-sizing:border-box}html,body{margin:0}body{background:var(--bg);color:var(--text);font:16px/1.6 var(--font);-webkit-font-smoothing:antialiased}#root{min-height:100vh;display:flex;flex-direction:column}main{flex:1;width:min(1080px,100% - 32px);margin:0 auto;padding:28px 0 56px;outline:none}h1,h2,h3,h4{line-height:1.25;margin:0 0 .5em}h1{font-size:clamp(1.75rem,3.5vw,2.5rem);letter-spacing:-.02em}h2{font-size:1.35rem}h3{font-size:1.05rem}p{margin:0 0 1em}a{color:var(--accent)}code{font-family:var(--mono);font-size:.9em;background:var(--surface-2);border:1px solid var(--line);border-radius:6px;padding:.05em .35em}img{max-width:100%}button,input,textarea{font:inherit;color:inherit}.muted{color:var(--muted)}.empty{text-align:center;padding:24px 8px}.eyebrow{text-transform:uppercase;letter-spacing:.08em;font-size:.75rem;font-weight:700;color:var(--muted);margin-bottom:.4em}.lead{font-size:1.1rem;color:var(--muted);max-width:62ch}.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}.skip-link{position:absolute;left:-999px;top:8px;background:var(--surface);padding:8px 12px;border-radius:8px;z-index:100}.skip-link:focus{left:8px}:focus-visible{outline:3px solid var(--accent);outline-offset:2px}.button{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:42px;padding:0 16px;border-radius:10px;border:1px solid var(--line);background:var(--surface);color:var(--text);font-weight:600;cursor:pointer;text-decoration:none;transition:background .15s,border-color .15s,transform .05s}.button:hover{border-color:var(--accent)}.button:active{transform:translateY(1px)}.button:disabled{opacity:.5;cursor:not-allowed}.button.primary{background:var(--accent);border-color:var(--accent);color:var(--accent-ink)}.button.primary:hover{filter:brightness(1.08)}.button.ghost{background:var(--accent-soft);border-color:transparent;color:var(--accent)}.button.done{background:var(--good-soft);border-color:var(--good);color:var(--good)}.button.wide{width:100%}.icon-button{display:inline-grid;place-items:center;width:42px;height:42px;border-radius:10px;border:1px solid var(--line);background:var(--surface);cursor:pointer}.text-button{display:inline-flex;align-items:center;gap:6px;background:none;border:0;padding:6px 0;color:var(--accent);font-weight:600;cursor:pointer}.text-button:disabled{color:var(--muted);cursor:not-allowed}.chip{border:1px solid var(--line);background:var(--surface);color:var(--text);border-radius:999px;padding:6px 12px;font-size:.88rem;cursor:pointer;min-height:34px}.chip:hover{border-color:var(--accent);color:var(--accent)}.chip:disabled{opacity:.5;cursor:not-allowed}.topbar{position:sticky;top:0;z-index:20;display:flex;align-items:center;gap:16px;padding:10px max(16px,calc((100% - 1080px)/2));background:color-mix(in srgb,var(--surface) 88%,transparent);-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);border-bottom:1px solid var(--line)}.brand{display:flex;align-items:center;gap:10px;color:var(--text);text-decoration:none;margin-right:auto;min-width:0}.brand-mark{display:grid;place-items:center;width:38px;height:38px;border-radius:10px;background:var(--accent);color:var(--accent-ink);font:700 1rem var(--mono);flex:none}.brand b{display:block;font-size:1rem;white-space:nowrap}.brand small{display:block;color:var(--muted);font-size:.78rem}.top-actions{display:flex;gap:8px}.picker{position:relative}.picker-button{display:flex;align-items:center;gap:8px;min-height:42px;min-width:190px;padding:0 12px;border-radius:10px;border:1px solid var(--line);background:var(--surface);cursor:pointer;font-weight:600}.picker-button span{flex:1;text-align:left}.picker-button img,.picker-list img{width:24px;height:24px}.picker-list{position:absolute;top:calc(100% + 6px);left:0;width:280px;max-height:70vh;overflow:auto;margin:0;padding:6px;list-style:none;background:var(--surface);border:1px solid var(--line);border-radius:12px;box-shadow:var(--shadow);z-index:30}.picker-list li{display:flex;align-items:center;gap:10px;padding:8px 10px;border-radius:8px;cursor:pointer;outline:none}.picker-list li.active,.picker-list li:focus{background:var(--accent-soft)}.picker-list li span{flex:1}.picker-list strong{display:block}.picker-list small{color:var(--muted)}.hero{padding:24px 0 8px}.hero h1{max-width:20ch}.continue-strip{margin:24px 0 8px}.continue-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:12px}.continue-card{position:relative;overflow:hidden;display:flex;align-items:center;gap:12px;padding:14px 16px;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);color:var(--text);text-decoration:none;box-shadow:var(--shadow)}.continue-card:hover{border-color:var(--accent)}.continue-card img{width:36px;height:36px}.continue-card span{flex:1;min-width:0}.continue-card small{display:block;color:var(--muted)}.continue-card strong{display:block;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.continue-card .bar{position:absolute;left:0;bottom:0;height:3px;background:var(--accent)}.language-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(190px,1fr));gap:12px}.language-card{position:relative;display:flex;flex-direction:column;align-items:flex-start;gap:6px;padding:18px;text-align:left;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);cursor:pointer;box-shadow:var(--shadow);transition:transform .15s,border-color .15s}.language-card:hover{transform:translateY(-2px);border-color:var(--accent)}.language-card img{width:44px;height:44px}.language-card strong{font-size:1.15rem}.language-card span{color:var(--muted);font-size:.85rem}.done-pill{position:absolute;top:14px;right:14px;background:var(--good-soft);color:var(--good);font-weight:700;font-size:.75rem;padding:2px 8px;border-radius:999px}section+section{margin-top:28px}.language-hero{display:grid;grid-template-columns:auto 1fr auto;gap:20px;align-items:center;padding:20px;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow)}.language-hero>img{width:72px;height:72px}.language-hero h1{margin-bottom:.2em}.language-hero .muted{margin:6px 0 0;font-size:.9rem}.hero-actions{display:flex;flex-direction:column;gap:8px}.start-note{max-width:32ch;margin:0;color:var(--muted);font-size:.88rem;text-align:right}.progress-line{height:8px;max-width:360px;background:var(--surface-2);border-radius:999px;overflow:hidden}.progress-line i{display:block;height:100%;background:var(--accent)}.track-bar{display:flex;flex-wrap:wrap;gap:12px;align-items:center;justify-content:space-between;margin:24px 0 12px}.tabs{display:flex;gap:4px;padding:4px;background:var(--surface-2);border-radius:12px;overflow-x:auto}.tabs button{display:inline-flex;align-items:center;gap:6px;border:0;background:none;padding:8px 14px;border-radius:9px;font-weight:600;color:var(--muted);cursor:pointer;white-space:nowrap;min-height:38px}.tabs button small{font-weight:500;opacity:.8}.tabs button.active{background:var(--surface);color:var(--text);box-shadow:0 1px 3px #0000001a}.search-box{display:flex;align-items:center;gap:8px;padding:0 12px;min-height:42px;background:var(--surface);border:1px solid var(--line);border-radius:10px;min-width:min(320px,100%)}.search-box input{border:0;outline:0;background:none;flex:1;min-width:0}.module-list{list-style:none;margin:0;padding:0;display:grid;gap:10px}.module-list a{display:flex;gap:14px;align-items:flex-start;padding:14px 16px;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);color:var(--text);text-decoration:none}.module-list a:hover{border-color:var(--accent)}.module-list .state{flex:none;margin-top:3px;color:var(--line)}.module-list a.complete .state{color:var(--good)}.module-meta{flex:1;min-width:0}.module-meta small{display:block;color:var(--muted);font-size:.8rem}.module-meta strong{display:block}.module-meta span{display:block;color:var(--muted);font-size:.92rem}.last-pill{flex:none;font-style:normal;font-size:.75rem;font-weight:700;color:var(--accent);background:var(--accent-soft);padding:2px 8px;border-radius:999px}.crumbs{display:flex;gap:8px;flex-wrap:wrap;font-size:.9rem;color:var(--muted);margin-bottom:14px}.crumbs a{color:var(--muted)}.lesson{display:grid;gap:20px}.lesson>section+section{margin-top:0}.lesson-hero{padding:24px;border-radius:var(--radius);background:linear-gradient(135deg,var(--accent-soft),var(--surface));border:1px solid var(--line)}.tags{display:flex;flex-wrap:wrap;gap:6px;margin-bottom:14px}.tags span{font-size:.78rem;font-weight:600;padding:2px 10px;border-radius:999px;background:var(--surface);border:1px solid var(--line)}.card{padding:22px;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow)}.outcomes ul,.practice ul,.practice ol,.notes{padding-left:1.2em;margin:0 0 1em}.outcomes li,.practice li{margin-bottom:.35em}.chapter{padding:4px 2px}.chapter h2{display:flex;gap:12px;align-items:center}.chapter-number{display:inline-grid;place-items:center;flex:none;width:32px;height:32px;border-radius:50%;background:var(--accent);color:var(--accent-ink);font-size:.95rem}.chapter p{max-width:72ch}.callout{border-left:4px solid var(--accent);background:var(--accent-soft);padding:12px 16px;border-radius:0 10px 10px 0;margin:0 0 1em;max-width:72ch}.flow{list-style:none;counter-reset:step;display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:10px;padding:0;margin:0 0 1em}.flow li{counter-increment:step;padding:12px;border:1px solid var(--line);border-radius:12px;background:var(--surface-2)}.flow li:before{content:counter(step);display:inline-grid;place-items:center;width:24px;height:24px;border-radius:50%;background:var(--accent);color:var(--accent-ink);font-size:.8rem;font-weight:700;margin-bottom:6px}.flow strong,.flow span{display:block}.flow span{color:var(--muted);font-size:.9rem}.code-window{border-radius:12px;overflow:hidden;border:1px solid var(--line);margin:0 0 1em}.code-toolbar{display:flex;justify-content:space-between;align-items:center;padding:6px 12px;background:var(--code-bg);color:var(--code-ink);font-size:.85rem}.code-toolbar .text-button{color:var(--code-ink)}.code-window pre,.code-block{margin:0;padding:14px 16px;background:var(--code-bg);color:var(--code-ink);overflow-x:auto;font:.88rem/1.55 var(--mono)}.code-window code,.code-block code{background:none;border:0;padding:0;color:inherit;font-size:inherit}.two-col{display:grid;grid-template-columns:1fr 1fr;gap:20px}.draft{display:grid;gap:6px;margin-bottom:1em}.draft small{color:var(--muted);font-weight:400}.draft textarea,.ask-form textarea{width:100%;padding:12px;border:1px solid var(--line);border-radius:10px;background:var(--surface-2);font-family:var(--mono);font-size:.9rem;resize:vertical}.hints{margin-bottom:1em}.hint{padding:10px 14px;background:var(--warn-soft);border:1px solid var(--warn-line);border-radius:10px}.options{min-width:0;border:0;padding:0;margin:0 0 1em;display:grid;gap:8px}.options legend{max-width:100%;overflow-wrap:anywhere;font-weight:600;margin-bottom:8px;padding:0}.options label{min-width:0;overflow-wrap:anywhere;display:flex;gap:10px;align-items:flex-start;padding:10px 12px;border:1px solid var(--line);border-radius:10px;cursor:pointer}.options label:hover{border-color:var(--accent)}.options label.correct{border-color:var(--good);background:var(--good-soft)}.options label.incorrect{border-color:var(--bad);background:var(--bad-soft)}.options input{margin-top:5px}.question{margin-bottom:18px}.why{font-size:.92rem;color:var(--muted);margin:0}.feedback{margin-top:12px;padding:10px 14px;border-radius:10px;background:var(--surface-2)}.feedback.correct{background:var(--good-soft);color:var(--good)}.feedback.incorrect{background:var(--bad-soft);color:var(--bad)}.ask-ai{display:flex;flex-wrap:wrap;align-items:center;gap:8px;margin-top:14px;padding-top:12px;border-top:1px dashed var(--line)}.ask-ai>span{display:inline-flex;align-items:center;gap:6px;font-size:.82rem;font-weight:700;color:var(--accent)}.resources ul{list-style:none;padding:0;margin:0;display:grid;gap:10px;grid-template-columns:repeat(auto-fill,minmax(260px,1fr))}.resources li{display:grid;gap:2px;padding:12px 14px;border:1px solid var(--line);border-radius:12px;background:var(--surface)}.resources li a{font-weight:600;display:inline-flex;gap:6px;align-items:center}.resources li span,.resources li small{color:var(--muted);font-size:.85rem}.completion{display:flex;gap:16px;align-items:center;justify-content:space-between;padding:20px 22px;border:1px solid var(--line);border-radius:var(--radius);background:var(--surface-2)}.completion h2{margin:0 0 4px}.completion p{margin:0}.pager{display:grid;grid-template-columns:1fr 1fr;gap:12px}.pager a{display:flex;gap:10px;align-items:center;padding:14px 16px;border:1px solid var(--line);border-radius:var(--radius);background:var(--surface);color:var(--text);text-decoration:none}.pager a:hover{border-color:var(--accent)}.pager a.next{justify-content:flex-end;text-align:right}.pager small{display:block;color:var(--muted)}.page-message{text-align:center;padding:64px 16px}.stepper{display:flex;gap:6px;overflow-x:auto;padding:8px;background:color-mix(in srgb,var(--bg) 92%,transparent);-webkit-backdrop-filter:blur(8px);backdrop-filter:blur(8px);border:1px solid var(--line);border-radius:12px;scrollbar-width:thin}.stepper button{display:inline-flex;align-items:center;gap:8px;flex:none;max-width:240px;min-height:38px;padding:6px 12px;border:1px solid transparent;border-radius:9px;background:none;color:var(--muted);font-weight:600;font-size:.88rem;cursor:pointer;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.stepper button span{display:inline-grid;place-items:center;flex:none;width:22px;height:22px;border-radius:50%;background:var(--surface-2);font-size:.75rem}.stepper button.past span{background:var(--good-soft);color:var(--good)}.stepper button.active{background:var(--surface);border-color:var(--accent);color:var(--text);box-shadow:0 1px 3px #00000014}.stepper button.active span{background:var(--accent);color:var(--accent-ink)}.step-body{display:grid;gap:20px;min-height:40vh}.lesson>*,.step-body>*,.card,.example{min-width:0}.step-preview{padding-left:1.2em;color:var(--muted)}.starter{margin-bottom:1em}.starter summary{cursor:pointer;font-weight:600;margin-bottom:8px}.done-tag{display:inline-flex;align-items:center;gap:4px;margin-left:auto;color:var(--good);font-weight:700}.lesson-hero{padding:20px 24px}.lesson-hero .lead{margin:0}.pager button{display:flex;gap:10px;align-items:center;padding:14px 16px;border:1px solid var(--line);border-radius:var(--radius);background:var(--surface);color:var(--text);cursor:pointer;text-align:left;font-weight:600}.pager button:hover{border-color:var(--accent)}.pager button.next{justify-content:flex-end;text-align:right}.modal-backdrop,.drawer-backdrop{position:fixed;inset:0;background:#0a0c1873;z-index:50;display:grid}.modal-backdrop{place-items:center;padding:16px}.modal{width:min(440px,100%);padding:24px;border-radius:18px;background:var(--surface);box-shadow:var(--shadow);text-align:center}.modal-logo{width:56px;height:56px}.modal-actions{display:grid;gap:8px;margin-top:16px}.modal-heading{display:flex;align-items:flex-start;justify-content:space-between;gap:16px;text-align:left}.modal-heading h2{margin:0}.help-panel{width:min(600px,100%);text-align:left}.help-panel ol{display:grid;gap:10px;padding-left:1.3em}.drawer-backdrop{justify-items:end}.drawer{width:min(460px,100%);height:100%;overflow-y:auto;background:var(--surface);padding:18px 20px 24px;display:flex;flex-direction:column;gap:14px;box-shadow:-8px 0 32px #0000002e}.drawer-head{display:flex;align-items:center;justify-content:space-between}.drawer-head h2{display:flex;align-items:center;gap:8px;margin:0;color:var(--accent)}.drawer-actions,.answer-actions{display:flex;align-items:center;justify-content:space-between;gap:10px}.drawer-actions .text-button{font-size:.82rem}.ai-warning{display:flex;gap:8px;align-items:flex-start;margin:0;padding:10px 12px;font-size:.85rem;background:var(--warn-soft);border:1px solid var(--warn-line);border-radius:10px}.ai-warning svg{flex:none;margin-top:3px}.account-form{display:grid;gap:10px}.account-form form{display:grid;gap:12px}.account-form label{display:grid;gap:4px;font-weight:600;font-size:.92rem}.account-form small{color:var(--muted);font-weight:400}.field-with-icon{display:flex;align-items:center;gap:8px;padding:0 12px;border:1px solid var(--line);border-radius:10px;background:var(--surface-2)}.field-with-icon input,.code-input{flex:1;min-height:42px;border:0;outline:0;background:none;min-width:0}.code-input{border:1px solid var(--line);border-radius:10px;background:var(--surface-2);padding:0 12px;letter-spacing:.4em;font:600 1.2rem var(--mono)}.form-message{display:flex;gap:8px;align-items:flex-start;padding:10px 12px;border-radius:10px;font-size:.9rem}.form-message.success{background:var(--good-soft);color:var(--good)}.form-message.error{background:var(--bad-soft);color:var(--bad)}.account-switch{display:flex;gap:8px;align-items:center;font-size:.92rem}.account-tools{display:grid;gap:8px;padding-top:8px;border-top:1px solid var(--line)}.account-settings{display:grid;gap:10px}.account-settings label{display:grid;gap:4px;font-size:.88rem;font-weight:600}.account-settings input{min-width:0;min-height:42px;padding:0 10px;border:1px solid var(--line);border-radius:9px;background:var(--surface-2)}.account-strip{display:flex;justify-content:space-between;align-items:center;gap:12px;padding:10px 12px;border:1px solid var(--line);border-radius:10px}.account-strip strong{display:block;overflow:hidden;text-overflow:ellipsis}.account-strip small{color:var(--muted)}.account-strip>div{min-width:0}.ask{display:flex;flex-direction:column;gap:10px;min-height:0;flex:1}.context-chip{margin:0;font-size:.85rem;color:var(--muted)}.thread{flex:1;min-height:200px;display:flex;flex-direction:column;gap:10px}.bubble{padding:10px 14px;border-radius:14px;max-width:94%;font-size:.95rem}.bubble p:last-child{margin-bottom:0}.bubble small{display:block;color:var(--muted);font-size:.75rem;margin-bottom:2px}.bubble.user{align-self:flex-end;background:var(--accent);color:var(--accent-ink)}.bubble.user small{color:inherit;opacity:.8}.bubble.assistant{align-self:flex-start;background:var(--surface-2)}.bubble.error{align-self:stretch;background:var(--bad-soft);color:var(--bad)}.bubble .ai-label,.search-answer .ai-label{margin:6px 0 0;font-style:italic}.answer-actions .text-button{font-size:.78rem;flex:none}.quota-message{display:grid;gap:4px;padding:14px;border:1px solid var(--warn-line);border-radius:12px;background:var(--warn-soft)}.quota-message span{color:var(--muted)}.typing{display:flex;gap:4px}.typing span{width:7px;height:7px;border-radius:50%;background:var(--muted);animation:blink 1s infinite ease-in-out}.typing span:nth-child(2){animation-delay:.15s}.typing span:nth-child(3){animation-delay:.3s}@keyframes blink{0%,80%,to{opacity:.25}40%{opacity:1}}.suggestions{display:flex;flex-wrap:wrap;gap:6px}.ask-form{display:flex;gap:8px;align-items:flex-end}.ask-form textarea{font-family:var(--font)}.ask-form .button{min-width:46px}.ai-search form{display:grid;gap:10px}.ai-search input[type=search]{min-height:44px;padding:0 12px;border:1px solid var(--line);border-radius:10px;background:var(--surface-2)}.scope{display:flex;gap:16px;font-size:.9rem}.search-answer{margin-top:14px}.hit-list{list-style:none;padding:0;margin:0 0 12px;display:grid;gap:8px}.hit-list a{display:block;padding:10px 12px;border:1px solid var(--line);border-radius:10px;text-decoration:none;color:var(--text)}.hit-list a:hover{border-color:var(--accent)}.hit-list span{display:block;font-size:.78rem;color:var(--muted)}.markdown h4{margin:.8em 0 .3em}.markdown ul,.markdown ol{padding-left:1.2em}.markdown .code-block{border-radius:10px;margin:0 0 1em}.footer{display:flex;flex-wrap:wrap;justify-content:space-between;gap:8px;padding:18px max(16px,calc((100% - 1080px)/2));border-top:1px solid var(--line);color:var(--muted);font-size:.85rem}@media(min-width:761px){.stepper{position:sticky;top:63px;z-index:10;flex-wrap:wrap;overflow:visible}}@media(max-width:760px){.topbar{flex-wrap:wrap;gap:10px}.brand{flex:1}.brand small{display:none}.brand b{overflow:hidden;text-overflow:ellipsis;font-size:.95rem}.brand>span:last-child{min-width:0}.picker{order:3;flex:1 1 100%}.picker-button,.picker-list{width:100%}.ai-button span{display:none}.language-hero{grid-template-columns:auto 1fr}.hero-actions{grid-column:1 / -1}.start-note{max-width:none;text-align:left}.two-col,.pager{grid-template-columns:1fr}.completion{flex-direction:column;align-items:stretch}.search-box{flex:1 1 100%}}
