:root{--bg:#070915;--panel:#11162a;--panel2:#151b33;--text:#e9eefc;--muted:#9aa6c7;--primary:#8b5cf6;--accent:#ec4899;--good:#22c55e;--bad:#ef4444;--warn:#f59e0b;--border:#27304f}*{box-sizing:border-box}body{margin:0;background:radial-gradient(circle at 20% 0%,rgba(139,92,246,.22),transparent 35%),radial-gradient(circle at 80% 10%,rgba(236,72,153,.16),transparent 35%),var(--bg);color:var(--text);font-family:Inter,system-ui,-apple-system,Segoe UI,Roboto,Arial,sans-serif;line-height:1.5}.nav{position:sticky;top:0;z-index:20;display:flex;align-items:center;justify-content:space-between;gap:1rem;padding:1rem 6vw;background:rgba(7,9,21,.86);backdrop-filter:blur(10px);border-bottom:1px solid var(--border)}.brand{font-weight:800;letter-spacing:.2px;color:#fff;text-decoration:none}.nav-links{display:flex;flex-wrap:wrap;align-items:center;gap:.5rem}.nav a{color:var(--muted);text-decoration:none;padding:.5rem .75rem;border-radius:12px}.nav a:hover,.nav a.active,.btn-nav{color:#fff;background:linear-gradient(135deg,rgba(139,92,246,.35),rgba(236,72,153,.25))}.container{max-width:1180px;margin:0 auto;padding:2rem 1rem;min-height:72vh}.hero{display:grid;grid-template-columns:1.4fr .8fr;gap:1.5rem;align-items:stretch}.card,.panel{background:linear-gradient(180deg,rgba(21,27,51,.96),rgba(17,22,42,.96));border:1px solid var(--border);border-radius:22px;padding:1.35rem;box-shadow:0 18px 50px rgba(0,0,0,.22)}.hero h1{font-size:clamp(2rem,5vw,4rem);line-height:1;margin:.3rem 0 1rem}.muted{color:var(--muted)}.grid{display:grid;gap:1rem}.grid-2{grid-template-columns:repeat(2,minmax(0,1fr))}.grid-3{grid-template-columns:repeat(3,minmax(0,1fr))}.stats{display:grid;grid-template-columns:repeat(3,1fr);gap:1rem}.stat{padding:1rem;border:1px solid var(--border);border-radius:18px;background:rgba(255,255,255,.03)}.stat strong{display:block;font-size:2rem}.btn,button,input[type=submit]{display:inline-block;border:0;border-radius:14px;background:linear-gradient(135deg,var(--primary),var(--accent));color:#fff;padding:.75rem 1rem;font-weight:700;text-decoration:none;cursor:pointer}.btn.secondary{background:#202846;color:#dbe4ff}.btn.danger{background:linear-gradient(135deg,#dc2626,#f97316)}.btn.small{padding:.45rem .7rem;font-size:.9rem}form{margin:0}.form-row{margin-bottom:1rem}label{display:block;margin-bottom:.35rem;color:#cbd5f5;font-weight:700}input,select,textarea{width:100%;padding:.8rem .9rem;border-radius:14px;border:1px solid var(--border);background:#0c1020;color:var(--text);outline:none}textarea{min-height:140px;resize:vertical}input:focus,select:focus,textarea:focus{border-color:var(--primary);box-shadow:0 0 0 3px rgba(139,92,246,.2)}.alert{padding:1rem;border-radius:14px;margin-bottom:1rem;border:1px solid var(--border)}.alert.success{background:rgba(34,197,94,.12);border-color:rgba(34,197,94,.35)}.alert.danger{background:rgba(239,68,68,.12);border-color:rgba(239,68,68,.35)}.alert.warning{background:rgba(245,158,11,.12);border-color:rgba(245,158,11,.35)}.alert.info{background:rgba(59,130,246,.12);border-color:rgba(59,130,246,.35)}.table{width:100%;border-collapse:collapse;overflow:hidden}.table th,.table td{text-align:left;padding:.8rem;border-bottom:1px solid var(--border);vertical-align:top}.table th{color:#c9d4ff;background:rgba(255,255,255,.04)}.badge{display:inline-block;padding:.25rem .6rem;border-radius:999px;background:#202846;color:#dbe4ff;font-size:.82rem}.badge.good{background:rgba(34,197,94,.15);color:#86efac}.badge.bad{background:rgba(239,68,68,.15);color:#fca5a5}.challenge-card{display:flex;flex-direction:column;gap:.75rem}.challenge-card.solved{border-color:rgba(34,197,94,.45)}.challenge-meta{display:flex;gap:.5rem;flex-wrap:wrap}.footer{display:flex;justify-content:space-between;gap:1rem;padding:1.5rem 6vw;color:var(--muted);border-top:1px solid var(--border)}.admin-nav{border-bottom-color:rgba(236,72,153,.35)}.actions{display:flex;gap:.5rem;flex-wrap:wrap}.code{font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;background:#060914;padding:.8rem;border-radius:14px;border:1px solid var(--border);overflow:auto}.rank{font-size:1.4rem;font-weight:800;color:#fff}.kpi{font-size:2rem;font-weight:900}.empty{padding:2rem;text-align:center;color:var(--muted);border:1px dashed var(--border);border-radius:18px}@media(max-width:760px){.hero,.grid-2,.grid-3,.stats{grid-template-columns:1fr}.nav{align-items:flex-start;flex-direction:column}.table{display:block;overflow-x:auto}.footer{flex-direction:column}}