:root{color-scheme:dark;--bg:#061426;--surface:#0d2038;--surface2:#081a2c;--line:#24486e;--text:#e8f1ff;--muted:#9bb0c9;--accent:#43d9ff;--ok:#4ade80}*{box-sizing:border-box}html{min-height:100%;scroll-behavior:smooth}body{margin:0;min-height:100vh;background:radial-gradient(circle at top,#0d2037 0,var(--bg) 42rem);color:var(--text);font:16px/1.6 system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif}main{max-width:1180px;margin:auto;padding:24px 18px 70px}a{color:var(--accent);margin-right:14px}nav{display:flex;gap:10px;flex-wrap:wrap;padding:8px 0 28px}.hero{text-align:center;padding:28px 0 22px}.eyebrow{color:#72ddff;font-size:.78rem;font-weight:850;letter-spacing:.12em}.hero h1{font-size:clamp(2.3rem,6vw,4.4rem);line-height:1;margin:12px 0}.hero p{max-width:760px;margin:auto;color:var(--muted)}.stats{display:inline-flex;gap:12px;align-items:center;margin-top:20px;padding:10px 14px;border:1px solid var(--line);border-radius:999px;background:var(--surface2)}.stats span{color:var(--muted);font-size:.9rem}.card{background:var(--surface);border:1px solid var(--line);border-radius:18px;padding:20px}.toolbar{display:grid;grid-template-columns:auto minmax(180px,1fr) auto minmax(180px,220px) auto;gap:10px;align-items:center;margin:10px 0 20px}.toolbar label{font-weight:800}.toolbar input,.toolbar select{width:100%;min-height:42px;border:1px solid #315b7e;border-radius:10px;background:#061426;color:var(--text);padding:9px 11px;font:inherit}.challenge-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px}.challenge{background:var(--surface);border:1px solid var(--line);border-radius:18px;padding:20px;min-width:0;transition:transform .15s,border-color .15s}.challenge:hover{transform:translateY(-2px);border-color:#43d9ff}.tag{display:inline-block;padding:3px 8px;border-radius:999px;background:#102d4b;color:#9fdcff;font-size:12px}.challenge h2{margin:9px 0 6px;font-size:1.2rem}.challenge p{color:var(--muted);min-height:50px}.challenge code{background:#020914;border-radius:6px;padding:2px 5px}.btn{border:1px solid #28627a;border-radius:10px;background:#1677ff;color:#fff;padding:9px 13px;font-weight:800;cursor:pointer}.btn:hover{filter:brightness(1.08)}.btn.done{background:#123d2a;border-color:#2b7d50;color:var(--ok)}.btn.secondary{background:#102d4b}.challenge.is-complete{border-color:#2b7d50}.challenge.is-hidden{display:none}@media(max-width:850px){.toolbar{grid-template-columns:1fr 1fr}.toolbar input,.toolbar select{grid-column:2}.toolbar label:nth-of-type(2){grid-column:1}.toolbar .btn{grid-column:1/3}.challenge-grid{grid-template-columns:1fr}}@media(max-width:600px){main{padding:18px 12px 48px}.stats{border-radius:14px;display:flex;flex-direction:column;gap:2px}.toolbar{grid-template-columns:1fr}.toolbar input,.toolbar select,.toolbar label,.toolbar .btn{grid-column:auto}.challenge{padding:17px}}@media(prefers-reduced-motion:reduce){*,*:before,*:after{transition:none!important;scroll-behavior:auto}}.challenge-celebration{position:fixed;inset:0;z-index:2000;display:grid;place-items:center;padding:20px;background:#020914aa;backdrop-filter:blur(5px);animation:celebrate-in .25s ease both}.celebration-card{width:min(420px,100%);padding:28px;border:1px solid #3d678b;border-radius:20px;background:#0d2038;box-shadow:0 25px 80px #0008;text-align:center;animation:celebrate-pop .45s ease both}.celebration-stars{font-size:2.4rem;letter-spacing:10px;animation:stars-pop .8s ease both}.celebration-card strong{display:block;font-size:1.35rem;margin-top:10px}.celebration-card p{color:#9bb0c9}.celebration-card button{border:1px solid #28627a;border-radius:10px;background:#1677ff;color:#fff;padding:10px 15px;font-weight:800;cursor:pointer}@keyframes celebrate-in{0%{opacity:0}to{opacity:1}}@keyframes celebrate-pop{0%{opacity:0;transform:translateY(15px) scale(.97)}to{opacity:1;transform:none}}@keyframes stars-pop{0%{opacity:0;transform:scale(.7)}to{opacity:1;transform:scale(1)}}@media(prefers-reduced-motion:reduce){.challenge-celebration,.celebration-card,.celebration-stars{animation:none}}