.Sudoku{
    display: flex;
    flex-direction: column;
}
.NonaRow,.CellRow{
    display: flex;
}
.Nona{
    border: 2px solid black;
}
.Cell{
    padding: 5px;
    width: 2em;
    height: 2em;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 150%;
    border: 1px solid gray;
}