title: How do you add custom styling to a tab when it's active in Bootstrap 4?
body: <p>I have these list items. When the active tab changes to <code>Page_1</code>, I'd like the <code>&lt;li&gt;</code> to have <code>border-bottom: solid 1px #000;</code> as opposed to Bootstrap's own styling/</p>
  
  <pre><code>&lt;ul class="nav nav-tabs"&gt;
  
      &lt;li&gt;&lt;a data-toggle="tab" href="#Home" role="tabpanel" class="nav- 
      link active"&gt;Home&lt;/a&gt;
      &lt;/li&gt;
  
      &lt;li&gt;&lt;a data-toggle="tab" href="#Page_1" role="tabpanel" class="nav- 
      link"&gt;Page 1&lt;/a&gt;
      &lt;/li&gt;
  
  &lt;/ul&gt;
  </code></pre>