@font-face{font-family:Pretendard;src:url('/static/fonts/Pretendard-Regular.subset.woff2') format('woff2');font-weight:400;font-display:swap}@font-face{font-family:Pretendard;src:url('/static/fonts/Pretendard-Bold.subset.woff2') format('woff2');font-weight:700;font-display:swap}
:root{color-scheme:dark;--bg:#10151c;--panel:#161e28;--line:#303b48;--text:#edf1f5;--muted:#adb8c5;--accent:#a5edb1;--amber:#edc387;font-family:Pretendard,system-ui,-apple-system,sans-serif;font-size:16px}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--text)}a{color:inherit;text-underline-offset:4px}button,input,#editor{font:inherit}button,summary{cursor:pointer}button{border:1px solid var(--accent);border-radius:7px;padding:10px 16px;background:var(--accent);color:#122218;font-weight:650}button:hover{filter:brightness(1.1)}button:disabled{opacity:.5;cursor:wait}.secondary{background:transparent;color:var(--muted);border-color:var(--line)}:focus-visible{outline:2px solid var(--accent);outline-offset:4px}[hidden]{display:none!important}header{max-width:1500px;margin:auto;padding:23px 40px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line);gap:16px}header a{text-decoration:none;font-size:14px}.brand{font-size:20px;font-weight:700}.brand span{color:var(--accent)}.lab-label{letter-spacing:2px;font:12px monospace;color:var(--muted)}.lab-label small{padding:4px 6px;border:1px solid var(--line);margin-left:9px}main{max-width:1500px;padding:0 40px;margin:auto}.intro{display:flex;justify-content:space-between;align-items:center;gap:32px;padding:40px 0 30px}.eyebrow{font-size:12px;letter-spacing:2px;color:var(--accent);font-weight:650;margin:0 0 12px}h1{font-size:clamp(26px,3vw,38px);letter-spacing:-1.3px;line-height:1.3;margin:0 0 13px}.intro p:not(.eyebrow){margin:0;color:var(--muted);line-height:1.7}.progress-box{width:145px;flex-shrink:0;color:var(--muted);font-size:14px}.progress-box>span:first-child{font:32px monospace;color:var(--text);display:block;margin-bottom:6px}progress{height:5px;width:100%;accent-color:var(--accent);display:block;margin-top:10px}#problem-nav{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;margin-bottom:24px}#problem-nav button{display:flex;align-items:center;gap:12px;text-align:left;background:transparent;color:var(--muted);border-color:var(--line);font-size:14px;padding:14px}#problem-nav button[aria-current=true]{background:#203128;color:var(--accent);border-color:#548a60}#problem-nav .number{font-family:monospace;font-size:17px}#problem-nav .completed{color:var(--accent)}.workspace{display:grid;grid-template-columns:minmax(0,.92fr) minmax(0,1.2fr);border:1px solid var(--line);border-radius:12px;overflow:hidden;background:var(--panel)}.problem-panel{padding:28px;border-right:1px solid var(--line);max-height:790px;overflow:auto;line-height:1.8}.problem-meta{display:flex;justify-content:space-between;font-size:12px;letter-spacing:1px;color:var(--accent)}#difficulty{color:var(--amber)}h2{font-size:25px;line-height:1.4;letter-spacing:-.6px;margin:14px 0}h3{font-size:15px;margin:24px 0 10px}#description p{margin:0 0 14px}code{font-family:Consolas,monospace;color:var(--accent);font-size:.94em}.formula{font:15px/1.8 Consolas,monospace;border-left:2px solid var(--accent);padding:10px 15px;background:#111820;overflow:auto;white-space:pre-wrap}.source{font-size:14px;color:var(--accent)}pre{font:14px/1.7 Consolas,'Courier New',monospace;white-space:pre-wrap;overflow-wrap:anywhere;background:#10161f;padding:15px;border-radius:6px;margin:10px 0}ul{padding-left:20px;font-size:15px;color:#c3ccd6}li{margin:7px 0}details{border-top:1px solid var(--line);padding:13px 0}summary{font-size:14px;color:var(--muted)}details p{font-size:14px;color:var(--muted)}.code-panel{display:flex;flex-direction:column;min-width:0}.editor-top{display:flex;justify-content:space-between;padding:17px 22px;background:#1a2430;font-size:14px;border-bottom:1px solid var(--line)}.editor-top span{color:var(--muted);font-size:12px}#editor{display:block;resize:vertical;width:100%;min-height:310px;height:355px;border:0;background:#101720;color:#dae6ef;font:15px/1.8 Consolas,'Courier New',monospace;padding:22px;tab-size:4;outline-offset:-3px!important;white-space:pre;overflow:auto}.toolbar{display:flex;justify-content:flex-end;gap:9px;align-items:center;padding:14px 17px;border-top:1px solid var(--line);border-bottom:1px solid var(--line);flex-wrap:wrap}.toolbar>span{margin-right:auto;font-size:12px;color:var(--muted)}kbd{font-size:11px;font-weight:400;margin-left:10px;opacity:.7}.results{padding:20px;min-height:200px;max-height:320px;overflow:auto}.results-head{display:flex;justify-content:space-between;align-items:center;gap:15px}.results h3{margin:0}.results #status{font-size:13px;color:var(--muted)}.muted{color:var(--muted);font-size:14px;line-height:1.8}.test-row{border-bottom:1px solid var(--line);padding:11px 0;font-size:14px}.test-row>div{display:flex;justify-content:space-between;gap:10px}.pass{color:var(--accent)}.fail{color:#ffb6ac}.test-row pre{font-size:12px;margin-bottom:0}.intuition{display:grid;grid-template-columns:1fr 1fr;gap:60px;padding:44px 5px;border-bottom:1px solid var(--line)}.intuition h2{font-size:23px}.intuition p:not(.eyebrow){color:var(--muted);font-size:14px;line-height:1.8;max-width:480px}.experiment label{display:flex;justify-content:space-between;font-size:14px;margin-bottom:12px}.experiment output{color:var(--accent);font-family:monospace}input[type=range]{width:100%;accent-color:var(--accent);margin:0 0 22px}.metrics{display:flex;gap:50px}.metrics span{display:block;color:var(--muted);font-size:12px;margin-bottom:8px}.metrics strong{font:27px monospace}.metrics>div:last-child strong{color:var(--accent)}footer{max-width:1500px;margin:auto;padding:25px 40px 35px;font-size:12px;color:var(--muted);line-height:1.8;display:flex;gap:40px;justify-content:space-between}footer span{white-space:nowrap}footer p{max-width:750px;margin:0}@media(min-width:1600px){.problem-panel{max-height:850px}#editor{height:400px}}@media(max-width:900px){main{padding:0 20px}header{padding:20px}.workspace{grid-template-columns:1fr}.problem-panel{max-height:none;border-right:0;border-bottom:1px solid var(--line)}#problem-nav{grid-template-columns:1fr 1fr}.intuition{gap:30px}.lab-label{display:none}footer{padding:25px 20px;display:block}footer p{margin-top:10px}}@media(max-width:550px){.intro{padding:28px 0;align-items:flex-start}.progress-box{width:70px}.progress-box>span:first-child{font-size:23px}.progress-box>span:nth-child(2){font-size:12px}.intro p:not(.eyebrow){font-size:14px}.eyebrow{font-size:10px}h1{font-size:27px}.problem-panel{padding:20px}.intuition{grid-template-columns:1fr;gap:20px}#problem-nav button{padding:11px;font-size:12px}.toolbar>span{width:100%}.editor-top{padding:14px}.editor-top span{font-size:10px}#editor{padding:15px;font-size:14px}header .brand{font-size:18px}}

.course-picker{display:flex;align-items:center;gap:15px;flex-wrap:wrap;margin:0 0 20px;font-size:14px}.course-picker label{color:var(--accent)}.course-picker select{font:inherit;background:var(--panel);color:var(--text);border:1px solid var(--line);border-radius:6px;padding:10px;max-width:100%}.course-picker>span{font-size:12px;color:var(--muted)}#problem-nav{grid-template-columns:repeat(auto-fit,minmax(150px,1fr))}.metrics{gap:24px;flex-wrap:wrap}.metrics strong{font-size:23px}.references{margin-top:15px}.references a{color:var(--accent)}@media(max-width:550px){#problem-nav{grid-template-columns:1fr 1fr}}

#course-nav{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:12px;margin-bottom:18px}#course-nav button{display:flex;flex-direction:column;align-items:flex-start;gap:10px;background:var(--panel);color:var(--text);border-color:var(--line);text-align:left;padding:18px}#course-nav button[aria-current=true]{border-color:var(--accent);background:#203128}#course-nav small{color:var(--muted);font-size:12px}#catalog{border:1px solid var(--line);border-radius:8px;padding:14px 18px}#catalog summary{color:var(--accent)}#catalog-list{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:0 24px}#catalog-list h3{color:var(--text)}#catalog-list a{line-height:1.7}#course-count{margin:20px 0 10px}@media(max-width:900px){#course-nav{grid-template-columns:1fr 1fr}}@media(max-width:550px){#course-nav button{padding:12px;font-size:13px}#catalog-list{grid-template-columns:1fr}}

.code-editor{width:100%;height:380px;min-height:310px;font-size:15px;line-height:1.8}.code-editor .ace_gutter{background:#151e29;color:#8999aa}.code-editor.ace-tomorrow-night{background:#101720}.code-editor .ace_text-input{min-height:0;height:1em;margin:0;padding:0;resize:none;border:0}.editor-help{font-size:12px;color:var(--muted);padding:9px 16px;margin:0;border-top:1px solid var(--line);line-height:1.7}.editor-top .filename{font-size:14px;color:var(--text)}

.connection{border-left:3px solid var(--amber);padding:10px 14px;background:#222830;color:#d5dce4;font-size:14px;line-height:1.8}.lesson-navigation{display:flex;justify-content:space-between;gap:18px;flex-wrap:wrap;border-top:1px solid var(--line);padding-top:20px;margin-top:12px}.lesson-navigation a{color:var(--accent);font-size:14px}.learning-result{color:var(--accent);font-size:12px;line-height:1.7}#helper-list code{overflow-wrap:anywhere}#helper-list a{font-size:12px}#course-nav{grid-template-columns:repeat(auto-fit,minmax(180px,1fr))}.formula{font-family:Cambria,"Times New Roman",serif;font-size:18px;line-height:2;overflow-wrap:anywhere}@media(max-width:550px){#course-nav{grid-template-columns:1fr 1fr}.formula{font-size:16px}}
.formula{font-family:inherit;font-size:16px;white-space:normal;overflow-x:auto;overflow-y:hidden;overflow-wrap:normal;padding:12px 15px}.formula .katex-display{margin:.45em 0}.formula .katex-display>.katex{text-align:left}.formula .katex{font-size:1.08em}#description .katex-display{line-height:normal}[data-math-error]{color:#ffb6ac}@media(max-width:550px){.formula{font-size:14px}}