settings-table-example.html

<table>
  <thead>
    <tr>
      <th>Setting</th>
      <th>Value</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>Setting A</td>
      <td>Value A</td>
    </tr>
    <tr colspan="2" class="js-hide">
      <td>
        <form>
        <input name="setting_a" />
        <button>Save</button>
      </form>
      </td>
    </tr>
  </tbody>
</table>