#game-board {
    display: flex;
    flex-direction: column;
    width: 300px;
    margin: 20px auto;
}

.row {
    display: flex;
}

.cell {
    width: 100px;
    height: 100px;
    border: 1px solid #000;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2em;
    cursor: pointer;
}

#message {
    text-align: center;
    font-size: 1.5em;
    margin-top: 20px;
}