:root{color-scheme:dark;font-family:Inter,system-ui,sans-serif;background:#080d18;color:#f8fafc}*{box-sizing:border-box}body{margin:0;min-height:100vh;background:radial-gradient(circle at 50% 8%,#4c1d9550,transparent 35%),#080d18}header{height:68px;padding:0 max(18px,4vw);display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid #ffffff18}a{color:#c4b5fd;text-decoration:none}.brand{color:#fff;font-size:20px;font-weight:850}.brand:first-letter{color:#facc15}main{width:min(1420px,96vw);margin:auto;padding:30px 0}.intro{text-align:center;max-width:780px;margin:0 auto 24px}.eyebrow{color:#a78bfa!important;font-weight:850;letter-spacing:.16em}.intro h1{font-size:clamp(32px,5vw,58px);margin:.15em 0}.intro p,.rules p,.rules li{color:#aeb7cb;line-height:1.55}.game-shell{display:grid;grid-template-columns:210px minmax(340px,690px) 270px;gap:22px;justify-content:center;align-items:start}.panel,.play{border:1px solid #ffffff1a;background:#111827dd;border-radius:22px;padding:20px;box-shadow:0 18px 55px #0008}.controls{display:grid;gap:13px}.controls label{display:grid;gap:6px;color:#aeb7cb;font-size:13px}.controls select,button{min-height:44px;border:1px solid #ffffff18;border-radius:11px;background:#1f2937;color:#f8fafc;padding:0 12px;font:inherit;cursor:pointer}.primary{background:linear-gradient(135deg,#7c3aed,#4f46e5);font-weight:750}.metric{display:flex;justify-content:space-between;padding:11px 0;border-top:1px solid #ffffff12;color:#aeb7cb}.metric b{color:#fff}.board{display:grid;grid-template-columns:repeat(9,1fr);aspect-ratio:1;border:4px solid #8b5cf6;border-radius:9px;overflow:hidden;background:#334155;gap:1px}.cell{position:relative;min-height:0;border:0;border-radius:0;background:#101827;font-size:clamp(17px,4.2vw,39px);padding:0}.cell.fixed{background:#202b3d;font-weight:850}.cell.hyper{background:#312e5a}.cell.hyper.fixed{background:#403b70}.cell.selected{background:#5b21b6;color:#fff;box-shadow:inset 0 0 0 3px #ddd6fe}.cell[data-box-right="1"]{border-right:3px solid #8b5cf6}.cell[data-box-bottom="1"]{border-bottom:3px solid #8b5cf6}.cell[data-cage-top="1"]{box-shadow:inset 0 2px #fbbf24}.cell[data-cage-bottom="1"]{border-bottom:2px solid #fbbf24}.cell[data-cage-left="1"]{border-left:2px solid #fbbf24}.cell[data-cage-right="1"]{border-right:2px solid #fbbf24}.cell.selected[data-cage-top="1"]{box-shadow:inset 0 2px #fbbf24,inset 0 0 0 3px #ddd6fe}.cage-sum{position:absolute;left:3px;top:1px;font-size:clamp(7px,1.4vw,11px);color:#fde68a;font-weight:800}.keypad{display:grid;grid-template-columns:repeat(9,1fr);gap:6px;margin:16px 0 9px}.keypad button{padding:0;font-size:20px;font-weight:750}.actions{display:grid;grid-template-columns:repeat(5,1fr);gap:7px}.actions button{padding:0 5px}.message{min-height:22px;text-align:center;color:#c4b5fd}.rules h2{margin-top:0}.rules ul{padding-left:20px}.proof{border-top:1px solid #ffffff16;padding-top:14px;color:#86efac!important}dialog{border:1px solid #ffffff22;border-radius:20px;background:#111827;color:#fff;padding:26px;max-width:430px}dialog::backdrop{background:#000c}dialog form{display:flex;gap:10px;justify-content:flex-end}@media(max-width:1080px){.game-shell{grid-template-columns:190px minmax(330px,650px)}.rules{grid-column:1/-1}}@media(max-width:720px){header{height:58px}.intro h1{font-size:34px}main{padding:18px 0}.game-shell{display:flex;flex-direction:column}.controls,.play,.rules{width:100%}.controls{grid-template-columns:1fr 1fr}.controls .metric{display:none}.play{padding:10px}.actions button{font-size:12px}.keypad{gap:3px}.keypad button{min-height:40px;font-size:17px}.cell{font-size:clamp(16px,8vw,30px)}}