.thead-inverse a should be white, not blue

Created by: hughbe

I'm migrating to bootstrap 4, and have the following html structure:

<table class="table">
  <thead class="thead-inverse">
    <tr>
      <th>#</th>
      <th><a>Created Time</a></th>
    </tr>
  </thead>
</table>

However, the anchor is styled as blue, not white: