title: How to change the toolbar color in Ionic 4
body: <p>I am working in my Ionic 4 app and I want to change the background color of the toolbar but it is not working.</p>
  
  <p><strong>This I have tried:</strong></p>
  
  <pre><code>ion-toolbar {
      --background: #f2f2f2;
  }
  
  ion-toolbar {
      background: #f2f2f2 !important;
  }
  </code></pre>
  
  <p>Like:</p>
  
  <blockquote>
    <p>color: var(--ion-color-contrast);</p>
  </blockquote>
  
  <p>where to define the <code>--ion-color-contrast</code>. In <code>variables.scss</code> file or some where else for changing the color.</p>
  
  <p>Can anyone help me how the define the variables in the <code>variables.scss</code> for changing the colors in <strong>Ionic 4</strong>.</p>