:root{color:#18202b;font-synthesis:none;text-rendering:optimizelegibility;-webkit-font-smoothing:antialiased;--border:#d8dee8;--muted:#5d6878;--panel:#fff;--ink:#111827;--blue:#93c5fd;--green:#2ac68a;--amber:#efd01e;--red:#f4393c;--code:#101624;background:#f5f7fb;font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif;line-height:1.5}*{box-sizing:border-box}body{min-width:320px;margin:0;overflow:hidden}button,input,select{font:inherit}button{cursor:pointer}.eyebrow{color:var(--blue);letter-spacing:.08em;text-transform:uppercase;margin:0 0 8px;font-size:.72rem;font-weight:800}.app-shell{height:100vh;min-height:100vh}.workspace{grid-template-columns:360px minmax(0,1fr);gap:0;width:100vw;max-width:none;height:100vh;margin:0;padding:0;display:grid}.sidebar{background:var(--panel);border:0;border-right:1px solid var(--border);border-radius:0;flex-direction:column;height:100vh;min-height:0;display:flex;overflow:hidden}.sidebar-heading{border-bottom:1px solid var(--border);align-items:center;gap:12px;min-height:76px;padding:16px 18px;display:flex}.sidebar-heading img{width:38px;height:38px}.sidebar-heading h1{color:var(--ink);letter-spacing:0;margin:0;font-size:1.1rem;line-height:1.1}.sidebar-heading p{color:var(--muted);margin:4px 0 0;font-size:.82rem}.sidebar__filters{gap:8px;padding:18px 20px 10px;display:grid}.field{gap:6px;display:grid}.field.problem-select{display:none}.field input,.field select,.problem-select-empty{color:var(--ink);background:#f8fafc;border:1px solid #cfd7e3;border-radius:6px;outline:none;width:100%;min-height:40px;padding:8px 10px}.problem-select-empty{color:var(--muted);border-style:dashed;align-items:center;display:grid}.field input:focus,.field select:focus{border-color:var(--blue);box-shadow:0 0 0 3px #2563eb29}.problem-count{color:var(--muted);margin:0 0 6px;font-size:.75rem;line-height:1.3}.problem-list{flex-direction:column;align-content:start;gap:10px;padding:8px 20px;display:flex;overflow:auto}.problem-list-empty{color:var(--muted);border:1px dashed #d8e2ee;border-radius:6px;gap:4px;padding:18px;display:grid}.problem-list-empty strong{color:var(--ink);font-size:.95rem;line-height:1.35}.problem-list-empty span{font-size:.82rem;line-height:1.45}.problem-list__item{color:var(--ink);text-align:left;background:#f8fafc;border:1px solid #e2e8f0;border-radius:6px;grid-template-columns:28px minmax(0,1fr);align-items:center;gap:10px;width:100%;min-height:fit-content;padding:12px 14px;display:grid;overflow:hidden}.problem-list__item:hover{background:#f1f5f9;border-color:#cbd5e1}.problem-list__item.active{background:#eef5ff;border-color:#b8d4ff}.problem-list__item.active .problem-list__number{background:var(--blue);color:#fff}.problem-list__content{gap:4px;min-width:0;display:grid}.problem-list__title{overflow-wrap:anywhere;white-space:normal;word-break:normal;font-weight:720;line-height:1.35}.problem-list__number{color:var(--blue);font-variant-numeric:tabular-nums;border-radius:6px;justify-content:center;align-items:center;width:28px;height:28px;font-family:SFMono-Regular,Consolas,Liberation Mono,Menlo,monospace;font-size:.82rem;font-weight:800;line-height:1;display:inline-grid}.problem-list__meta{color:var(--muted);flex-wrap:wrap;align-items:center;gap:6px 8px;min-width:0;font-size:.78rem;line-height:1.2;display:flex}.difficulty-text{font-size:.74rem;font-weight:800;display:inline-flex}.difficulty--easy{color:var(--green)}.difficulty--medium{color:var(--amber)}.difficulty--hard{color:var(--red)}.detail{background:var(--panel);border:0;border-radius:0;min-width:0;height:100vh;min-height:0;padding:28px;overflow:auto}.detail__head{border-bottom:1px solid var(--border);justify-content:space-between;align-items:center;gap:24px;padding-bottom:24px;display:flex}.detail__head h1{letter-spacing:0;margin:0;font-size:clamp(1.75rem,3vw,2.5rem);line-height:1.1}.badge{border-radius:999px;padding:5px 8px;font-size:.74rem;font-weight:800;line-height:1;display:inline-flex}.badge--easy{color:var(--green);background:#dcfce7}.badge--medium{color:var(--amber);background:#fef3c7}.badge--hard{color:var(--red);background:#ffe4e6}.detail__metrics{color:var(--muted);white-space:nowrap;place-items:end;gap:4px;font-size:.86rem;display:grid}.prompt-section{border-bottom:1px solid var(--border);gap:18px;padding:24px 0;display:grid}.prompt-section h2{color:var(--ink);margin:0;font-size:1.06rem;line-height:1.35}.rich-text{border-left:3px solid #93c5fd;gap:12px;padding-left:16px;display:grid}.rich-text p{color:#46515f;margin:0;font-size:.95rem;line-height:1.75}.rich-text code{color:#1d4ed8;background:#eef6ff;border:1px solid #bfdbfe;border-radius:5px;padding:1px 5px;font-family:SFMono-Regular,Consolas,Liberation Mono,Menlo,monospace;font-size:.92em}.examples-block{gap:10px;display:grid}.examples-block h3{color:var(--muted);letter-spacing:.08em;text-transform:uppercase;margin:0;font-size:.75rem;font-weight:800}.example-list{gap:10px;display:grid}.example-card{background:#f8fafc;border:1px solid #dce3ed;border-radius:8px;gap:10px;padding:14px;display:grid}.example-card h4{color:var(--ink);margin:0;font-size:.9rem}.example-card dl{gap:8px;margin:0;display:grid}.example-card dl div{gap:3px;display:grid}.example-card dt{color:var(--muted);letter-spacing:.06em;text-transform:uppercase;font-size:.72rem;font-weight:800}.example-card dd{color:#46515f;overflow-wrap:anywhere;margin:0;font-family:SFMono-Regular,Consolas,Liberation Mono,Menlo,monospace;font-size:.86rem;line-height:1.55}.requirements-block{gap:10px;display:grid}.requirements-block h3{color:var(--muted);letter-spacing:.08em;text-transform:uppercase;margin:0;font-size:.75rem;font-weight:800}.requirements-block ul{gap:7px;margin:0;padding:0;list-style:none;display:grid}.requirements-block li{color:#46515f;padding-left:18px;font-size:.9rem;line-height:1.6;position:relative}.requirements-block li:before{background:var(--blue);content:"";border-radius:50%;width:6px;height:6px;position:absolute;top:.72em;left:0}.empty-state{background:var(--panel);text-align:center;border:0;border-radius:0;align-content:center;justify-items:center;height:100vh;min-height:0;padding:28px;display:grid}.empty-state h2{margin:0}.empty-state p:not(.eyebrow){color:var(--muted)}.solution-section{min-width:0}.approach-selector{border:1px solid var(--border);background:#f8fafc;border-radius:8px;margin-top:24px;padding:16px}.approach-header{justify-content:space-between;align-items:baseline;gap:16px;margin-bottom:12px;display:flex}.approach-header h2{color:var(--ink);margin:0;font-size:1rem;line-height:1.35}.approach-tabs{flex-wrap:wrap;gap:8px;display:flex}.approach-tabs button{background:var(--panel);color:#46515f;text-align:left;border:1px solid #dce3ed;border-radius:8px;min-width:112px;min-height:42px;padding:9px 12px;font-weight:700}.approach-tabs button.active{border-color:var(--blue);box-shadow:inset 3px 0 0 var(--blue);color:var(--blue);background:#eef5ff}.approach-tabs button:focus-visible{outline:2px solid var(--blue);outline-offset:2px}.code-panel{background:var(--code);color:#e5edf8;border-radius:8px;margin-top:14px;overflow:hidden}.code-panel__header{border-bottom:1px solid #ffffff1a;justify-content:space-between;align-items:center;gap:16px;padding:16px 18px;display:flex}.code-panel__header h3{margin:0;font-size:1.1rem}.segmented{background:#1c2637;border:1px solid #324158;border-radius:7px;grid-template-columns:1fr 1fr;padding:3px;display:inline-grid}.segmented button{color:#b9c6d8;background:0 0;border:0;border-radius:5px;min-width:44px;min-height:30px;font-weight:800}.segmented button.active{color:#111827;background:#e5edf8}.code-block{tab-size:2;margin:0;padding:18px;font-family:SFMono-Regular,Consolas,Liberation Mono,Menlo,monospace;font-size:.88rem;line-height:1.65;overflow:auto}.code-block code{color:#dce7f3;white-space:pre-wrap;display:block}.token.comment,.token.prolog,.token.doctype,.token.cdata{color:#7b8794}.token.punctuation{color:#b6c2d1}.token.namespace{opacity:.72}.token.property,.token.tag,.token.boolean,.token.number,.token.constant,.token.symbol,.token.deleted{color:#f78c6c}.token.selector,.token.attr-name,.token.string,.token.char,.token.builtin,.token.inserted{color:#c3e88d}.token.operator,.token.entity,.token.url,.token.variable{color:#89ddff}.token.atrule,.token.attr-value,.token.function,.token.class-name{color:#82aaff}.token.keyword{color:#c792ea}.token.regex,.token.important{color:#ffcb6b}@media (width<=900px){body{overflow:auto}.app-shell{height:auto}.workspace{grid-template-columns:1fr;height:auto;min-height:100vh;padding:0}.sidebar,.detail,.empty-state{border-radius:0;height:auto;min-height:auto}.sidebar{border-bottom:1px solid var(--border);border-right:0}.detail,.empty-state{margin-top:0}.field.problem-select{display:grid}.problem-list{display:none}.detail__head{display:grid}.detail__metrics{justify-items:start}.prompt-section{padding:18px 0}.rich-text{padding-left:12px}.approach-selector{padding:14px}.approach-header{display:block}.approach-tabs{grid-template-columns:1fr;display:grid}}@media (width<=560px){.detail{padding:20px}.code-panel__header{flex-direction:column;align-items:start}}