.container {
    text-align: center;
}

.board {
    display: inline-grid;
    grid-template-columns: repeat(3, 100px);
    grid-gap: 5px;
}

.cell {
    width: 100px;
    height: 100px;
    background-color: lightgray;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2em;
    cursor: pointer;
}

button {
    margin-top: 20px;
    font-size: 1.2em;
    padding: 10px 20px;
}