title: Bootstrap 4, bg-inverse not showing?
body: <p>Trying to follow the navbar example in Bootstraps documentation, I have a problem where the background colour of the navbar doesn't get loaded.</p>
  
  <pre><code>&lt;nav class="navbar navbar-inverse bg-inverse"&gt;
      &lt;a class="navbar-brand" href="#"&gt;Navbar&lt;/a&gt;
  &lt;/nav&gt; 
  </code></pre>
  
  <p>I took a look in bootstrap.css and bg-inverse does not appear there. Am I supposed to create the colours myself, or am I doing something wrong? (I am working in an Angular project)</p>