.app{font-family:Arial,sans-serif;text-align:center;padding:20px}.grid{display:grid;grid-template-columns:repeat(3,80px);grid-template-rows:repeat(3,80px);gap:5px;justify-content:center;margin-top:20px}.tile{background-color:#4caf50;color:#fff;display:flex;align-items:center;justify-content:center;font-size:2em;cursor:pointer;border-radius:8px;-webkit-user-select:none;user-select:none;transition:all .3s ease}.tile.empty{background-color:#eee;cursor:default}button{margin:10px;padding:10px 20px;font-size:1em;cursor:pointer}