title: css3 "::after" pseudo-element not working
body: <p>I want to add a triangle after a div tag.Therefore i used css3 after pseudo-element. But it's not working. Following is my css rule.</p>
  
  <pre><code>.header-wrapper .part1 ::after {
      width: 0;
      height: 0;
      border-left: solid 48.35px #f21e1e;
      border-bottom: solid 48.35px transparent;
      border-top: solid 48.35px transparent;
  }
  </code></pre>
  
  <p>Following is my html part</p>
  
  <pre><code>&lt;div class="header-wrapper"&gt;
      &lt;div class="part1"&gt;&lt;/div&gt;
  &lt;/div&gt;
  </code></pre>