: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% 10%,#27205c55,transparent 35%),#080d18}header{height:72px;padding:0 max(20px,4vw);display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid #ffffff18}a{color:#c4b5fd;text-decoration:none}.brand{font-size:20px;font-weight:800;color:#fff}.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{font-size:clamp(34px,6vw,64px);margin:.2em 0}.intro p{color:#aeb7cb;line-height:1.6}.eyebrow{color:#a78bfa!important;font-weight:800;letter-spacing:.18em}.game-shell{display:grid;grid-template-columns:220px minmax(300px,720px) 260px;gap:24px;justify-content:center;align-items:start}.panel,.play{border:1px solid #ffffff1a;background:#111827cc;border-radius:22px;padding:22px;box-shadow:0 20px 60px #0008}.controls{display:grid;gap:14px}.controls label{display:grid;gap:7px;color:#aeb7cb;font-size:13px}.controls select,button{min-height:44px;border:1px solid #ffffff18;border-radius:12px;background:#1f2937;color:#f8fafc;padding:0 14px;font:inherit;cursor:pointer}.primary{background:linear-gradient(135deg,#7c3aed,#4f46e5);font-weight:700}.metric{display:flex;justify-content:space-between;padding:12px 0;border-top:1px solid #ffffff12;color:#aeb7cb}.metric b{color:#fff}.board-wrap{width:min(100%,650px);margin:auto}.board{--size:4;display:grid;grid-template-columns:repeat(var(--size),1fr);aspect-ratio:1;border:4px solid #8b5cf6;border-radius:10px;overflow:hidden;background:#334155;gap:1px}.cell{min-height:0;border:0;border-radius:0;background:#111827;font-size:clamp(24px,6vw,54px);padding:0}.cell.fixed{background:#1f2937;font-weight:800;color:#f8fafc}.cell.selected{background:#4c1d95;color:#fff;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{display:grid;grid-template-columns:repeat(6,1fr);gap:8px;margin:18px auto 10px;max-width:650px}.keypad button{font-size:22px;font-weight:700}.actions{display:grid;grid-template-columns:repeat(5,1fr);gap:8px;max-width:650px;margin:auto}.actions button{padding:0 8px}.message{min-height:24px;text-align:center;color:#c4b5fd}.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{border:1px solid #ffffff22;border-radius:20px;background:#111827;color:#fff;padding:28px;max-width:420px}dialog::backdrop{background:#000b}dialog form{display:flex;gap:10px;justify-content:flex-end}@media(max-width:1050px){.game-shell{grid-template-columns:180px minmax(300px,650px)}.rules{grid-column:1/-1}}@media(max-width:720px){main{padding:20px 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:12px}.actions{grid-template-columns:repeat(5,1fr)}.actions button{font-size:12px;padding:0 3px}.keypad{gap:5px}header{height:58px}.intro h1{font-size:36px}}