setting table width

HTML

<table id="main">
    <colgroup>
        <col style="width:75px">
        <col class="one">
        <col class="two">
        <col class="three">
        <col style="width:75px">
   </colgroup>
                <tbody>
                    <tr>
                        <td class="restricted-cell">restricted cell</td>
                        <td class="one">one</td>
                        <td class="two">two</td>
                        <td class="three">three</td>
                        <td class="restricted-cell">restricted cell</td>
                    </tr>
                </tbody>
</table>

CSS

#main {
    table-layout: fixed;
    width: 500px;
}

table, th, td {
    border: 1px solid black;
}

.restricted-cell {
    width: 75px;
}

.three {
    display: none;
}