:root{--bg:#0d0f13;--panel:#111419;--edge:#1e232b;--text:#d7dce4;--muted:#6c7686;--ok:#4ade80;--bad:#f87171;--accent:#7dd3fc;--lightningcss-light: ;--lightningcss-dark:initial;color-scheme:dark}*{box-sizing:border-box}html,body,#root{height:100%;margin:0}body{background:var(--bg);color:var(--text);-webkit-font-smoothing:antialiased;font:14px/1.6 ui-sans-serif,-apple-system,Segoe UI,system-ui,sans-serif}.app{flex-direction:column;height:100%;display:flex}.bar{border-bottom:1px solid var(--edge);justify-content:space-between;align-items:center;gap:16px;height:44px;padding:0 16px;font-size:13px;display:flex}.mark{letter-spacing:.06em;text-transform:uppercase;color:var(--muted);font-size:11px;font-weight:600}.stepper{color:var(--muted);font-variant-numeric:tabular-nums;align-items:center;gap:10px;display:flex}.score{color:var(--muted);font-variant-numeric:tabular-nums}.score em{color:var(--accent);font-style:normal}.body{flex:1;min-height:0;display:flex}.editor{flex:1;min-width:0}.editor.booting{color:var(--muted);justify-content:center;align-items:center;font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:12px;display:flex}.rail{border-left:1px solid var(--edge);background:var(--panel);flex-direction:column;flex:none;gap:22px;width:360px;padding:20px;display:flex;overflow-y:auto}.rail h1{margin:0 0 6px;font-size:15px;font-weight:600}.rail h2{letter-spacing:.08em;text-transform:uppercase;color:var(--muted);align-items:center;gap:8px;margin:0 0 8px;font-size:11px;font-weight:600;display:flex}.prompt{color:#aeb6c2;margin:0}.muted{color:var(--muted);margin:0}.dot{background:#333a45;border-radius:50%;width:6px;height:6px}.dot.ok{background:var(--ok)}.dot.bad{background:var(--bad)}button{font:inherit;color:var(--text);border:1px solid var(--edge);cursor:pointer;background:#171b22;border-radius:6px;padding:6px 12px;transition:background .12s,border-color .12s}button:hover:not(:disabled){background:#1d222b;border-color:#2b323d}button:disabled{opacity:.5;cursor:default}.actions{gap:8px;display:flex}.actions .primary{background:var(--accent);border-color:var(--accent);color:#06121b;font-weight:600}.actions .primary:hover:not(:disabled){background:#a5e3ff;border-color:#a5e3ff}kbd{font:inherit;opacity:.6;margin-left:4px;font-size:11px}.link{color:var(--accent);text-align:left;background:0 0;border:none;padding:0}.link:hover{background:0 0;text-decoration:underline}.solved{color:var(--ok);margin:0}.issues,.results,.hints ol{flex-direction:column;gap:8px;margin:0;padding:0;list-style:none;display:flex}.issues li{color:var(--bad);font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:12px;line-height:1.5}.line{color:var(--muted);margin-right:6px}.results li{gap:8px;font-size:13px;display:flex}.results li>span{flex:none;width:12px}.results .pass>span{color:var(--ok)}.results .fail>span{color:var(--bad)}.results em{color:var(--bad);margin-top:2px;font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:12px;font-style:normal;display:block}.fault{color:var(--bad);margin:0;font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:12px}.hints{border-top:1px solid var(--edge);flex-direction:column;gap:10px;margin-top:auto;padding-top:18px;display:flex}.hints ol{counter-reset:hint}.hints li{counter-increment:hint;color:#aeb6c2;padding-left:22px;position:relative}.hints pre{border:1px solid var(--edge);color:#c8d3e0;white-space:pre;background:#0a0c10;border-radius:6px;margin:8px 0 0;padding:10px 12px;font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:12px;line-height:1.55;overflow-x:auto}.hints li:before{content:counter(hint);color:var(--muted);font-variant-numeric:tabular-nums;font-size:12px;position:absolute;top:0;left:0}@media (max-width:900px){.body{flex-direction:column}.rail{border-left:none;border-top:1px solid var(--edge);width:100%;max-height:45%}.editor{min-height:50vh}}