title: apply background to element:after dynamically with ngStyle
body: <p>I'm applying a background to a div like so:</p>
  
  <pre><code>&lt;div class="bgimg"&gt;test&lt;/div&gt;
  
  .bgimg {
    padding-top: 10px;
    &amp;::after {
      background: url('/assets/img/test.png') no-repeat center center;
    }
  }
  </code></pre>
  
  <p>The path to the image is dynamic and stored in the component:</p>
  
  <pre><code>export class MyComponent {
  
    myImage: string = "/assets/img/test.png";
  </code></pre>
  
  <p>So to my div element I want to apply an ngStyle but I don't know how to specify :after</p>
  
  <pre><code>&lt;div
    [ngStyle]="background: url('{myImage}') no-repeat center center;"&gt;
    test
  &lt;/div&gt;
  </code></pre>