title: How to change text color in mat-button using custom theme
body: <p>In using this <a href="https://medium.com/@tomastrajan/the-complete-guide-to-angular-material-themes-4d165a9d24d1" rel="nofollow noreferrer">document</a>.  In attempting to change the text color in a mat-button I added a theme.scss to 
  the css project.  Here is the theme.scss code:</p>
  
  <pre><code>@import '~@angular/material/theming';
  @include mat-core();
  
  $candy-app-primary: mat-palette($mat-indigo, 700, 300, 900);
  $candy-app-accent:  mat-palette($mat-light-blue, A400);
  $candy-app-warn:    mat-palette($mat-deep-orange, A200);
  
  $candy-app-theme: mat-light-theme($candy-app-primary, $candy-app-accent, 
  $candy-app-warn);
  
  @include angular-material-theme($candy-app-theme);
  </code></pre>
  
  <p>This is the html file:</p>
  
  <pre><code> &lt;button  mat-raised-button color="accent" routerLink="/"&gt;Home&lt;/button&gt;
  </code></pre>
  
  <p>The accent color shows the expected accent, mat-light-blue, color.  The text inside the button is still gray.  The A400 is not displaying white as expected.</p>