title: Fade in border on hover
body: <p>I want to fade in a border on hover. I have the following but it starts off as nothing then goes to a 1px grey line (grey is default color) and then eventually goes to a 2px red line.</p>
  
  <p>What am I going wrong?</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="false" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-css lang-css prettyprint-override"><code>a{ 
      border-bottom: none;
      transition: border-bottom 1s;
  }
  a:hover{
      border-bottom: 2px solid red;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;a href='#'&gt;hover here&lt;/a&gt;</code></pre>
  </div>
  </div>
  </p>