Bootstrap 4, bg-inverse not showing? : <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>
