title: How to set color of toggle buttons
body: <p>I have group of toggle buttons. They are very light and disappear in the background on poor monitors with a high brightness level.</p>
  
  <p><a href="https://i.stack.imgur.com/M6dKR.png" rel="noreferrer"><img src="https://i.stack.imgur.com/M6dKR.png" alt="enter image description here"></a></p>
  
  <p>How can I properly style them? I would prefer to assign them the <em>accent</em> or <em>primary</em> colors, the way you can do it for regular buttons.</p>
  
  <p>In may case, the primary and accent colors are dark. So they text should become white (with some transparency). For regular buttons, it automatically works.</p>
  
  <pre><code>&lt;div class="output-size"&gt;
    &lt;mat-button-toggle-group&gt;
      &lt;mat-button-toggle value="letter"&gt;Letter&lt;/mat-button-toggle&gt;
      &lt;mat-button-toggle value="legal"&gt;Legal&lt;/mat-button-toggle&gt;
      &lt;mat-button-toggle value="a4"&gt;A4&lt;/mat-button-toggle&gt;
      &lt;mat-button-toggle value="a5"&gt;A5&lt;/mat-button-toggle&gt;
    &lt;/mat-button-toggle-group&gt;
  &lt;/div&gt;
  </code></pre>