<table border="1" style="width: 100%; height: 100px;">
  <colgroup>
    <col>
    <col span="2" style="background-color:blue;">
    <col style="background-color:red;">
  </colgroup>
  <tr>
    <td></td>
    <td></td>
    <td></td>
    <td></td>
    <td></td>
  </tr>
  <tr>
    <td></td>
    <td></td>
    <td></td>
    <td></td>
    <td></td>
  </tr>
</table>

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