:root{--bg:#081019;--surface:#0f1b28;--surface2:#142434;--card:#101e2b;--line:#274054;--text:#edf7ff;--muted:#8fa6b8;--accent:#53e0b4;--accent2:#84b7ff;--danger:#ff7185;--warning:#ffc863;--shadow:0 18px 50px rgba(0,0,0,.28);--radius:22px;--board:#eaf3f7;--boardText:#102331;--given:#0b2838;--cell:#f8fcff;--cellAlt:#eef7fb;--select:#a8e7d7;--related:#d8f2eb}
:root[data-theme=light]{--bg:#f4f7f9;--surface:#fff;--surface2:#f0f5f7;--card:#fff;--line:#dce6eb;--text:#10212c;--muted:#687b88;--accent:#087e66;--accent2:#2866b5;--danger:#bf3349;--warning:#9e6500;--shadow:0 14px 40px rgba(24,48,63,.12);--board:#dce9ee;--boardText:#132833;--given:#183947;--cell:#fff;--cellAlt:#f5fafc;--select:#afe7d8;--related:#e2f4ef}
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var(--line)}.btn:hover{transform:translateY(-1px)}.btn-primary{background:linear-gradient(135deg,var(--accent),#63d7f3);color:#06151c;border-color:transparent}.btn-danger{background:color-mix(in srgb,var(--danger) 18%,var(--surface));color:var(--danger)}.btn-ghost{background:transparent}.stats-card{padding:22px;display:grid;grid-template-columns:1fr 1fr;gap:12px}.stat{padding:18px;background:var(--surface2);border:1px solid var(--line);border-radius:16px}.stat strong{display:block;font-size:28px;line-height:1.1}.stat span{color:var(--muted);font-size:13px}.section{margin-top:34px}.section-head{display:flex;align-items:end;justify-content:space-between;gap:16px;margin-bottom:15px}.section-head h2{margin:0;font-size:25px;letter-spacing:-.03em}.section-head p{margin:2px 0 0;color:var(--muted)}.grid{display:grid;grid-template-columns:repeat(4,1fr);gap:15px}.grid-3{grid-template-columns:repeat(3,1fr)}.grid-2{grid-template-columns:repeat(2,1fr)}.category-card,.challenge-card{padding:20px;text-decoration:none;color:var(--text);transition:.2s}.category-card:hover,.challenge-card:hover{transform:translateY(-3px);border-color:color-mix(in srgb,var(--accent) 45%,var(--line))}.difficulty{display:inline-flex;padding:5px 9px;border-radius:999px;background:color-mix(in srgb,var(--accent2) 12%,var(--surface2));color:var(--accent2);font-size:12px;font-weight:800}.category-card h3,.challenge-card h3{margin:12px 0 7px}.muted{color:var(--muted)}.challenge-meta{display:flex;gap:12px;flex-wrap:wrap;color:var(--muted);font-size:13px;margin-top:12px}.video-thumb{aspect-ratio:16/9;background:var(--surface2);border-radius:14px;overflow:hidden;margin-bottom:14px}.video-thumb img{width:100%;height:100%;object-fit:cover}.game-shell{display:grid;grid-template-columns:minmax(0,1fr) minmax(360px,520px);gap:24px;align-items:start}.video-panel,.game-panel{padding:18px}.video-wrap{position:relative;aspect-ratio:16/9;min-height:200px;overflow:hidden;border-radius:16px;background:#000}.video-wrap iframe{position:absolute;inset:0;width:100%;height:100%;border:0}.mode-tabs{display:flex;gap:8px;flex-wrap:wrap;margin:14px 0}.mode-tabs button{flex:1;min-width:110px}.game-toolbar{display:grid;grid-template-columns:repeat(4,1fr);gap:8px;margin-bottom:12px}.metric{padding:10px 8px;text-align:center;border:1px solid var(--line);background:var(--surface2);border-radius:12px}.metric strong{display:block;font-size:17px}.metric span{font-size:11px;color:var(--muted);text-transform:uppercase;letter-spacing:.07em}.sudoku-board{display:grid;grid-template-columns:repeat(9,1fr);aspect-ratio:1;width:100%;background:var(--board);border:3px solid var(--boardText);border-radius:12px;overflow:hidden;user-select:none}.sudoku-cell{position:relative;display:grid;place-items:center;background:var(--cell);color:var(--boardText);font-size:clamp(18px,3.2vw,32px);font-weight:600;border-right:1px solid #b9cbd2;border-bottom:1px solid #b9cbd2;cursor:pointer}.sudoku-cell:nth-child(3n){border-right:2px solid var(--boardText)}.sudoku-cell:nth-child(9n){border-right:0}.sudoku-cell:nth-child(n+19):nth-child(-n+27),.sudoku-cell:nth-child(n+46):nth-child(-n+54){border-bottom:2px solid var(--boardText)}.sudoku-cell.given{font-weight:900;color:var(--given);background:var(--cellAlt)}.sudoku-cell.related{background:var(--related)}.sudoku-cell.selected{background:var(--select)}.sudoku-cell.error{animation:shake .25s;color:var(--danger)}@keyframes shake{25%{transform:translateX(-3px)}75%{transform:translateX(3px)}}.notes-grid{position:absolute;inset:3px;display:grid;grid-template-columns:repeat(3,1fr);font-size:9px;font-weight:700;color:#54717f;line-height:1}.number-pad{display:grid;grid-template-columns:repeat(9,1fr);gap:6px;margin-top:12px}.num-btn{aspect-ratio:1;border:1px solid var(--line);border-radius:11px;background:var(--surface2);color:var(--text);font-weight:850;font-size:18px;cursor:pointer}.game-actions{display:grid;grid-template-columns:repeat(4,1fr);gap:7px;margin-top:8px}.game-actions button{padding:10px 7px}.result-card{padding:24px;text-align:center}.result-score{font-size:52px;font-weight:900;letter-spacing:-.05em}.result-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:8px;margin:18px 0}.result-grid .stat{padding:12px}.form-card{max-width:540px;margin:30px auto;padding:28px}.form-card h1{margin-top:0}.field{margin:15px 0}.field label{display:block;font-size:13px;color:var(--muted);font-weight:700;margin-bottom:6px}.input,.select,.textarea{width:100%;border:1px solid var(--line);background:var(--surface2);color:var(--text);border-radius:12px;padding:12px 13px;outline:none}.textarea{min-height:120px;resize:vertical}.input:focus,.select:focus,.textarea:focus{border-color:var(--accent)}.alert{padding:11px 13px;border-radius:12px;background:color-mix(in srgb,var(--danger) 12%,var(--surface));color:var(--danger);border:1px solid color-mix(in srgb,var(--danger) 35%,var(--line));margin:12px 0}.success{color:var(--accent);background:color-mix(in srgb,var(--accent) 10%,var(--surface));border-color:color-mix(in srgb,var(--accent) 35%,var(--line))}.table-wrap{overflow:auto;border:1px solid var(--line);border-radius:16px}.table{width:100%;border-collapse:collapse;min-width:680px;background:var(--surface)}.table th,.table td{padding:12px 14px;text-align:left;border-bottom:1px solid var(--line)}.table th{font-size:12px;text-transform:uppercase;letter-spacing:.08em;color:var(--muted);background:var(--surface2)}.table tr:last-child td{border-bottom:0}.profile-head{display:flex;justify-content:space-between;align-items:center;gap:20px;padding:26px}.profile-name{font-size:30px;font-weight:900}.admin-shell{display:grid;grid-template-columns:230px 1fr;gap:20px}.admin-nav{padding:14px;position:sticky;top:90px}.admin-nav a{display:block;color:var(--muted);text-decoration:none;padding:10px 12px;border-radius:10px}.admin-nav a:hover,.admin-nav a.active{background:var(--surface2);color:var(--text)}.admin-content .card{padding:22px}.solver-layout{display:grid;grid-template-columns:minmax(340px,560px) 1fr;gap:22px}.solver-steps{max-height:650px;overflow:auto}.solver-step{padding:11px;border-bottom:1px solid var(--line);cursor:pointer}.solver-step.active{background:color-mix(in srgb,var(--accent) 10%,var(--surface2))}.solver-step b{display:block}.recording .topbar,.recording .footer,.recording .admin-nav,.recording .record-hide{display:none!important}.recording .site-main{width:min(760px,calc(100% - 20px));padding:20px 0}.recording .solver-layout{display:block}.recording .solver-layout>div:last-child{display:none}.toast{position:fixed;right:20px;bottom:20px;background:#07151d;color:#fff;padding:12px 16px;border-radius:12px;box-shadow:var(--shadow);opacity:0;transform:translateY(8px);transition:.2s;z-index:100}.toast.show{opacity:1;transform:none}.footer{width:min(1220px,calc(100% - 32px));margin:0 auto;border-top:1px solid var(--line);padding:22px 0 40px;display:flex;justify-content:space-between;color:var(--muted)}.empty{padding:30px;text-align:center;color:var(--muted)}
@media(max-width:920px){.navlinks{display:none}.topbar{padding:0 16px}.hero{grid-template-columns:1fr}.hero-card{padding:30px}.grid,.grid-3{grid-template-columns:repeat(2,1fr)}.game-shell,.solver-layout,.admin-shell{grid-template-columns:1fr}.admin-nav{position:static;display:flex;overflow:auto;gap:4px}.admin-nav a{white-space:nowrap}.game-panel{order:1}.video-panel{order:2}.site-main{padding-top:20px}.result-grid{grid-template-columns:repeat(2,1fr)}}
@media(max-width:560px){.site-main{width:min(100% - 20px,1220px)}.brand span:last-child{display:none}.grid,.grid-3,.grid-2{grid-template-columns:1fr}.hero-card{padding:24px;min-height:310px}.hero h1{font-size:40px}.hero p{font-size:16px}.stats-card{padding:14px}.game-panel,.video-panel{padding:12px}.game-toolbar{grid-template-columns:repeat(4,1fr);gap:5px}.metric{padding:8px 4px}.metric strong{font-size:15px}.number-pad{gap:4px}.num-btn{font-size:16px}.game-actions{grid-template-columns:repeat(2,1fr)}.sudoku-cell{font-size:clamp(18px,7vw,29px)}.footer{flex-direction:column;gap:5px}.profile-head{align-items:flex-start;flex-direction:column}}

.name-banner{width:min(1220px,calc(100% - 32px));margin:14px auto 0;padding:12px 14px;border:1px solid color-mix(in srgb,var(--accent) 35%,var(--line));background:color-mix(in srgb,var(--accent) 8%,var(--surface));border-radius:16px;display:flex;align-items:center;justify-content:space-between;gap:14px}.name-banner strong{display:block}.name-banner span{display:block;color:var(--muted);font-size:13px}.name-banner-form{display:flex;gap:8px;min-width:min(420px,45vw)}.name-banner-form .input{margin:0}@media(max-width:700px){.name-banner{align-items:stretch;flex-direction:column}.name-banner-form{min-width:0;width:100%}}

.recording .admin-shell{display:block}.challenge-shell .video-panel{align-self:start}@media(max-width:920px){.challenge-shell .video-panel{order:1}.challenge-shell .game-panel{order:2}}