:root{color-scheme:dark;color:#f8fafc;background:#080d18;font-family:Inter,system-ui,sans-serif}*{box-sizing:border-box}body{background:radial-gradient(circle at 50% 10%,#27205c55,#0000 35%),#080d18;min-height:100vh;margin:0}header{border-bottom:1px solid #ffffff18;justify-content:space-between;align-items:center;height:72px;padding:0 max(20px,4vw);display:flex}a{color:#c4b5fd;text-decoration:none}.brand{color:#fff;font-size:20px;font-weight:800}.brand:first-letter{color:#facc15}main{width:min(1420px,96vw);margin:auto;padding:38px 0}.intro{text-align:center;max-width:760px;margin:0 auto 28px}.intro h1{margin:.2em 0;font-size:clamp(34px,6vw,64px)}.intro p{color:#aeb7cb;line-height:1.6}.eyebrow{letter-spacing:.18em;font-weight:800;color:#a78bfa!important}.game-shell{grid-template-columns:220px minmax(300px,720px) 260px;justify-content:center;align-items:start;gap:24px;display:grid}.panel,.play{background:#111827cc;border:1px solid #ffffff1a;border-radius:22px;padding:22px;box-shadow:0 20px 60px #0008}.controls{gap:14px;display:grid}.controls label{color:#aeb7cb;gap:7px;font-size:13px;display:grid}.controls select,button{color:#f8fafc;min-height:44px;font:inherit;cursor:pointer;background:#1f2937;border:1px solid #ffffff18;border-radius:12px;padding:0 14px}.primary{background:linear-gradient(135deg,#7c3aed,#4f46e5);font-weight:700}.metric{color:#aeb7cb;border-top:1px solid #ffffff12;justify-content:space-between;padding:12px 0;display:flex}.metric b{color:#fff}.board-wrap{width:min(100%,650px);margin:auto}.board{--size:4;grid-template-columns:repeat(var(--size),1fr);aspect-ratio:1;background:#334155;border:4px solid #8b5cf6;border-radius:10px;gap:1px;display:grid;overflow:hidden}.cell{background:#111827;border:0;border-radius:0;min-height:0;padding:0;font-size:clamp(24px,6vw,54px)}.cell.fixed{color:#f8fafc;background:#1f2937;font-weight:800}.cell.selected{color:#fff;background:#4c1d95;box-shadow:inset 0 0 0 3px #c4b5fd}.cell[data-box-right="1"]{border-right:4px solid #8b5cf6}.cell[data-box-bottom="1"]{border-bottom:4px solid #8b5cf6}.keypad{grid-template-columns:repeat(6,1fr);gap:8px;max-width:650px;margin:18px auto 10px;display:grid}.keypad button{font-size:22px;font-weight:700}.actions{grid-template-columns:repeat(5,1fr);gap:8px;max-width:650px;margin:auto;display:grid}.actions button{padding:0 8px}.message{text-align:center;color:#c4b5fd;min-height:24px}.rules h2{margin-top:0}.rules p,.rules li{color:#aeb7cb;line-height:1.6}.rules ul{padding-left:20px}.proof{border-top:1px solid #ffffff14;padding-top:14px;color:#86efac!important}dialog{color:#fff;background:#111827;border:1px solid #fff2;border-radius:20px;max-width:420px;padding:28px}dialog::backdrop{background:#000b}dialog form{justify-content:flex-end;gap:10px;display:flex}@media (width<=1050px){.game-shell{grid-template-columns:180px minmax(300px,650px)}.rules{grid-column:1/-1}}@media (width<=720px){main{padding:20px 0}.game-shell{flex-direction:column;display:flex}.controls,.play,.rules{width:100%}.controls{grid-template-columns:1fr 1fr}.controls .metric{display:none}.play{padding:12px}.actions{grid-template-columns:repeat(5,1fr)}.actions button{padding:0 3px;font-size:12px}.keypad{gap:5px}header{height:58px}.intro h1{font-size:36px}}