<!DOCTYPE html>
<html>
<head>
<style>
table { background: white }
col { background: green }
td { color: white }
</style>
</head>
<body>
<table>
<col id="x" span="2">
<tr>
<td>One</td>
<td>Two</td>
<td>Three</td>
</tr>
</table>
</body>
</html>