body {
    display: flex;
    flex-direction: column;
    align-items: center;
    font-family: Arial, sans-serif;
}
#board {
    display: grid;
    grid-template-columns: repeat(3, 100px);
    gap: 5px;
}
.cell {
    width: 100px;
    height: 100px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 36px;
    background-color: #f0f0f0;
    cursor: pointer;
}
.cell:hover {
    background-color: #ddd;
}