title: External CSS: How to implement a class from a external css?
body: <p>I'm having trouble figuring out how to use this class from my external css:</p>
  
  <pre><code>.row.rectanglebox {
      margin-top:30px;
      margin-bottom:30px;
      height: 210px;
      border: solid black;
      padding: 20px;
  }
  </code></pre>
  
  <p>I've tried adding the following (which I normally would use) but to no avail:</p>
  
  <pre><code>&lt;div class="rectanglebox"&gt;
         &lt;p&gt; sample text &lt;/p&gt;
  &lt;div&gt;
  </code></pre>
  
  <p>What I'm trying to achieve is the following image:</p>
  
  <p><a href="https://i.stack.imgur.com/Gq8d5.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Gq8d5.png" alt="enter image description here"></a></p>