HTML 테이블 Colgroups에서 텍스트 정렬을 제어할 수 있습니까?

<code class="html"><table id="myTable" cellspacing="5">
    <colgroup id="names"></colgroup>
    <colgroup id="col20" class="datacol"></colgroup>
    <colgroup id="col19" class="datacol"></colgroup>
    <colgroup id="col18" class="datacol"></colgroup>

    <thead>
        <th> </th>
        <th>20</th>
        <th>19</th>
        <th>18</th>
    </thead>
    <tbody>
        <tr>
            <td> </td>
            <td> </td>
            <td> </td>
            <td> </td>
        </tr>
    </tbody>
</table></code>

<code class="css">#names {
    width: 200px;
}

#myTable .datacol {
    text-align: center;
    background-color: red;
}</code>

<code class="css">#myTable tbody td { text-align: center }
#myTable tbody td:first-child { text-align: left }</code>