:root{--bg1: #10132b;--bg2: #1a1f44;--panel: rgba(255, 255, 255, .06);--tile: linear-gradient(145deg, #5b8cff, #3b6ef0);--tile-solved: linear-gradient(145deg, #34d399, #10b981);--text: #eef1ff;--muted: #aab0d8;--accent: #ffd166}*{box-sizing:border-box}html,body{margin:0}body{font-family:system-ui,-apple-system,Segoe UI,Roboto,sans-serif;color:var(--text);background:radial-gradient(1200px 800px at 20% -10%,#2a2f6b 0%,transparent 60%),linear-gradient(160deg,var(--bg1),var(--bg2));min-height:100vh;display:flex;justify-content:center;align-items:center}#app{width:min(620px,96vw);padding:24px 12px 48px}h1{margin:0;font-size:2.2rem;letter-spacing:.5px}.tagline{color:var(--muted);margin:6px 0 18px}.controls,.ai-controls,.stats{display:flex;gap:10px;flex-wrap:wrap;align-items:center}.controls{margin-bottom:12px}.stats{justify-content:space-between;background:var(--panel);border-radius:12px;padding:10px 14px;margin:6px 0 14px}.stats strong{color:var(--accent);font-variant-numeric:tabular-nums}label{display:inline-flex;flex-direction:column;font-size:.78rem;color:var(--muted);gap:4px}select,button{font:inherit;color:var(--text);background:#ffffff14;border:1px solid rgba(255,255,255,.14);border-radius:10px;padding:9px 14px;cursor:pointer}button:hover{background:#ffffff29}button:active{transform:translateY(1px)}.ai-controls{margin-top:16px;justify-content:center}.board{position:relative;--n: 4;--board: min(90vw, 62vh, 560px);--cell: calc(var(--board) / var(--n));width:var(--board);height:var(--board);margin:8px auto;background:#00000047;border-radius:16px}.tile{position:absolute;top:0;left:0;width:calc(var(--cell) - 8px);height:calc(var(--cell) - 8px);margin:0;border:none;border-radius:12px;background:var(--tile);color:#fff;font-weight:700;font-size:calc(var(--cell) / 2.6);display:flex;align-items:center;justify-content:center;transition:transform .13s ease,background .2s ease,box-shadow .2s ease;will-change:transform;box-shadow:inset 0 -3px #0000002e}.board.solved .tile{background:var(--tile-solved)}.tile.hint{background:linear-gradient(145deg,#ffd166,#f59e0b);color:#3a2a00;box-shadow:0 0 0 3px #fff,0 0 22px 4px var(--accent);z-index:2}.status{min-height:1.4em;text-align:center;font-size:1.05rem;margin:14px 0 0;color:var(--accent)}.thinking{color:var(--muted);font-style:italic}.footer{margin-top:22px;text-align:center;color:var(--muted);font-size:.82rem}.footer kbd{background:#ffffff1f;border-radius:5px;padding:1px 5px;font-family:inherit;font-size:.9em}.tools{display:flex;gap:10px;flex-wrap:wrap;align-items:center;margin-bottom:12px}button:disabled{opacity:.4;cursor:not-allowed}button:disabled:hover{background:#ffffff14}.filebtn{flex-direction:row;font-size:inherit;color:var(--text);background:#ffffff14;border:1px solid rgba(255,255,255,.14);border-radius:10px;padding:9px 14px;cursor:pointer}.filebtn:hover{background:#ffffff29}.board.image .tile{align-items:flex-start;justify-content:flex-start;padding:5px 7px;font-size:calc(var(--cell) / 4.5);background-repeat:no-repeat;text-shadow:0 1px 2px rgba(0,0,0,.85),0 0 6px rgba(0,0,0,.6)}