Set table first column width in CSS

HTML & CSS
1

Dear all, for my table below, how can i set the width of the first column please?

<table>
    <thead>
        <tr>
            <th></th>
            <th>Standard</th>
            <th>Performance</th>
            <th>Ultimate</th>
        </tr>
    </thead>
    <tbody>
        <tr>
            <th scope="row">desc</th>
            <td>a</td>
            <td>b</td>
            <td>c</td>
        </tr>
    </tbody>
</table>

Please note I have tried a selector on the below but it doesn’t affect the column width:


tbody tr th
{
text-align:right;
column-width: 250px;
}
2

Try this…


tbody th{
text-align:right;
}
th:nth-child(1){
     width:250px;
}