:root{color-scheme:dark;font-family:ui-sans-serif,system-ui,-apple-system,Segoe UI,Roboto,sans-serif;line-height:1.5}*{box-sizing:border-box}html,body,#root{margin:0;min-height:100vh;background:#0a0a0a;color:#fafafa}.shell{min-height:100vh;display:grid;place-items:center;padding:2rem}.puzzle-container{display:flex;flex-direction:column;align-items:center;gap:1.25rem}h1{margin:0;font-size:1.75rem;font-weight:700;letter-spacing:-.02em}.puzzle-info{display:flex;gap:1.5rem;align-items:center;font-size:.95rem}.moves{color:#ffffffa6}.win-msg{color:#4ade80;font-weight:600}.puzzle-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:6px;width:min(380px,90vw);aspect-ratio:1}.tile{display:grid;place-items:center;font-size:1.5rem;font-weight:700;border:none;border-radius:8px;cursor:pointer;background:#1e1e2e;color:#fafafa;transition:background .15s,transform .1s;-webkit-user-select:none;user-select:none}.tile:hover:not(.empty):not(:disabled){background:#313147;transform:scale(1.04)}.tile:active:not(.empty){transform:scale(.96)}.tile.correct{color:#4ade80}.tile.empty{background:#ffffff08;cursor:default}.shuffle-btn{margin-top:.5rem;padding:.6rem 2rem;font-size:.95rem;font-weight:600;border:1px solid rgba(255,255,255,.15);border-radius:8px;background:#ffffff0f;color:#fafafa;cursor:pointer;transition:background .15s}.shuffle-btn:hover{background:#ffffff1f}