:root{--bg:#050816;--panel:#0b1226;--line:rgba(148,163,184,.18);--text:#f8fafc;--muted:#9eafc9;--accent:#60a5fa}*{box-sizing:border-box}body{margin:0;background:radial-gradient(circle at 10% 0,color-mix(in srgb,var(--accent) 18%,transparent),transparent 28%),var(--bg);color:var(--text);font-family:Inter,system-ui,sans-serif}.container{width:min(1100px,calc(100% - 30px));margin:auto}.page{padding:24px 0 70px}.back{display:inline-flex;gap:8px;align-items:center;color:#b9c7dd;text-decoration:none;border:1px solid var(--line);padding:10px 14px;border-radius:13px;background:rgba(15,23,42,.75)}.hero{margin-top:20px;border:1px solid var(--line);border-radius:28px;padding:34px;background:linear-gradient(145deg,rgba(15,23,42,.97),rgba(10,16,34,.98));display:grid;grid-template-columns:1fr .75fr;gap:25px;align-items:center}.hero img{width:100%;max-height:275px;object-fit:contain}.hero h1{font-size:clamp(38px,5vw,60px);margin:7px 0 12px}.hero p{color:#b7c6da;line-height:1.7}.pill{display:inline-flex;border:1px solid color-mix(in srgb,var(--accent) 40%,transparent);background:color-mix(in srgb,var(--accent) 10%,transparent);color:color-mix(in srgb,var(--accent) 75%,white);padding:7px 11px;border-radius:999px;font-size:12px;font-weight:900;text-transform:uppercase}.topics{display:flex;gap:8px;flex-wrap:wrap;margin:25px 0}.topic-btn{border:1px solid var(--line);background:rgba(255,255,255,.04);color:#b8c7dd;padding:9px 12px;border-radius:11px;font:inherit;font-weight:800;cursor:pointer}.topic-btn.active{background:var(--accent);border-color:var(--accent);color:#07111f}.tasks{display:grid;grid-template-columns:repeat(2,1fr);gap:17px}.task{border:1px solid var(--line);border-radius:22px;padding:22px;background:linear-gradient(160deg,rgba(15,23,42,.95),rgba(7,12,25,.99));display:flex;flex-direction:column}.task h3{font-size:21px;margin:12px 0 8px}.task p{color:#cbd5e1;line-height:1.65}.meta{display:flex;gap:7px;flex-wrap:wrap}.tag{padding:5px 8px;border-radius:999px;border:1px solid var(--line);font-size:10px;text-transform:uppercase;font-weight:900;color:#cbd5e1}.task pre{white-space:pre-wrap;background:#020617;border:1px solid #22304a;border-radius:13px;padding:13px;color:#dbeafe;overflow:auto}.task textarea{width:100%;min-height:190px;background:#020617;color:#e2e8f0;border:1px solid #22304a;border-radius:13px;padding:13px;font:14px/1.55 ui-monospace,monospace;resize:vertical}.actions{display:flex;gap:9px;flex-wrap:wrap;margin-top:auto;padding-top:15px}.btn{border:0;border-radius:12px;padding:10px 13px;font:inherit;font-weight:900;cursor:pointer;color:white;background:linear-gradient(135deg,var(--accent),#7c3aed)}.btn.secondary{background:rgba(255,255,255,.055);border:1px solid var(--line);color:#dbeafe}.solution{display:none;margin-top:12px;padding:13px;border-radius:13px;background:rgba(96,165,250,.07);border:1px solid rgba(96,165,250,.2);color:#c6d5e9;white-space:pre-wrap}.solution.open{display:block}.run-status{font-size:12px;color:#93a4bd;margin-top:8px}.test-results{display:grid;gap:6px;margin-top:8px}.result{font:12px monospace;padding:8px;border-radius:9px}.result.ok{background:rgba(16,185,129,.1);color:#86efac}.result.bad{background:rgba(239,68,68,.1);color:#fca5a5}.hidden{display:none!important}@media(max-width:800px){.hero{grid-template-columns:1fr}.tasks{grid-template-columns:1fr}}