title: Angular Material 2: mdStepper Header icon bg color change
body: <p>Is it possible to change the mdStepper step icon background color? I tried this:</p>
  
  <pre><code>.mat-step-header .mat-step-icon {
    background-color: #bb092d;
    color: rgba(255,255,255,.87);
  }
  </code></pre>
  
  <p>But it doesn't work :(</p>