title: CSS Transition on hover:after
body: <p>I have a code:</p>
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-css lang-css prettyprint-override"><code>ul {
    width: 160px;
  }
  
  ul li a {
    padding-bottom: 40px;
  }
  
  ul li  a {
          position: relative;
          display: block;
          transition: all .3s ease-in;
     }
  
      ul li a:hover:after {
          content: '';
          width: 26px;
          height: 10px;
          background-color: #10c3a2;
          position: absolute;
          top: 30px;
          left: 0;
          display: block;
      }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;ul&gt;
    &lt;li&gt;&lt;a href=""&gt;Item&lt;/a&gt;
    &lt;li&gt;&lt;a href=""&gt;Item&lt;/a&gt;
  &lt;/ul&gt;</code></pre>
  </div>
  </div>
  </p>
  <p>Why the transition is not working on hover:after? I tried to put the transition on hover and in after but it's not working. How I can resolve this issue?</p>