body {
    font-family: sans-serif;
    display: flex;
    flex-direction: column;
    align-items: center;
}

#game-board {
    display: grid;
    grid-template-columns: repeat(3, 100px);
    grid-template-rows: repeat(3, 100px);
    gap: 5px;
    margin-bottom: 20px;
}

.cell {
    width: 100px;
    height: 100px;
    border: 1px solid black;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 50px;
    cursor: pointer;
}

.cell.x::before {
    content: 'X';
}

.cell.o::before {
    content: 'O';
}