JSFiddle - React, Tailwind, and code Playground

HTML

<div>
  <table>
    <thead>
      <tr>
        <th>&nbsp;</th>
        <th>aaa</th>
        <th>aaa</th>
        <th>aaa</th>
        <th>aaa</th>
        <th>aaa</th>
        <th>aaa</th>
        <th>aaa</th>
        <th>aaa</th>
        <th>aaa</th>
      </tr>
    </thead>
    <tbody>
      <tr>
        <td>Cell</td>
        <td>Cell</td>
        <td>Cell</td>
        <td>Cell</td>
        <td>Cell</td>
        <td>Cell</td>
        <td>Cell</td>
        <td>Cell</td>
        <td>Cell</td>
        <td>Cell</td>
      </tr>
      <tr>
        <td>Cell</td>
        <td>Cell</td>
        <td>Cell</td>
        <td>Cell</td>
        <td>Cell</td>
        <td>Cell</td>
        <td>Cell</td>
        <td>Cell</td>
        <td>Cell</td>
        <td>Cell</td>
      </tr>
    </tbody>

  </table>
</div>

CSS

table {
  table-layout:fixed;
  border-collapse: collapse;
  background-color: white;
}

td,
th {
  border: 1px solid #999;
  padding: 0.25em;
  text-align: left;
  width: 400px; // If uncommented, rule is ignored
}