.chess-square {
    width: 40px;
    height: 40px;
    font-size: 1.2em;
    text-align: center;
    line-height: 40px;
    cursor: pointer;
}

#chess-board {
    display: grid;
    grid-template-columns: repeat(8, 40px);
    border: 2px solid #888;
    margin: 20px auto;
    width: 320px;
}