setting the width of a html table td
===

I have the following code:

    <table>
     <thead>
        <th class='1'>Date</th>
        <th class='2'>Start Time</th>
        <th class='3'>End Time </th>
        <th class='4'>Location</th>
    </thead>
      <tbody>
        <td class='1'>Date</td>
        <td class='2'>Start Time</td>
        <td class='3'>End Time </td>
        <td class='4'>Location</td>
    </tbody>
    </table>​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​

and the css 

     table {width:550px;}
    ​.1 {width:60px; background-color:green;}
    .2 {width:90px; background-color:blue;}
    .3 {width:90px; background-color:red;}
    .4 {width:100px; background-color:yellow;}​

Why can't I set the width? The background color isn't changing either so I must have a code error.