title: Change initial color of an Angular 9 mat-input
body: <p>I have a standard matInput field inside a standard mat-form-field, which is in a standard [formGroup] div. The background of the parent area is dark and the default color of the input is dark. That doesn't work well. Here's a sample of the HTML..</p>
  <pre><code>&lt;div [formGroup]=&quot;myInfo&quot;&gt;
    Year: &amp;nbsp;
    &lt;mat-form-field&gt;
      &lt;input class=&quot;myClass&quot; style=&quot;color: white&quot; matInput (keypress)=&quot;numericOnly($event)&quot; placeholder='YYYY' 
             formControlName=&quot;yearControl&quot;&gt;
    &lt;/mat-form-field&gt;
  &lt;/div&gt;
  </code></pre>
  <p>Looking online and based on answers here, I see how to change things in the .scss like:</p>
  <pre><code>.childClass {
    input { color: #fff !important; }
    label.mat-input-placeholder { color: #fff !important; }
    ::ng-deep .mat-form-field-label { color: #fff !important; }
    ::ng-deep .mat-form-field-ripple { color: #fff !important; }
    ::ng-deep .mat-form-field-underline { color: #fff !important; }
  }
  </code></pre>
  <p>This finally changed the placeholder text and entered text to be white, but the underline is still black. Thanks for your ongoing suggestions.</p>