title: How can I show three columns per row?
body: <p>I have been trying to show three columns per row. Is it possible using flexbox?</p>
  
  <p>My current CSS is something like this:</p>
  
  <pre><code>.mainDiv {
      display: flex;
      margin-left: 221px;
      margin-top: 43px;
  }
  </code></pre>
  
  <p>This code puts all content in a single row.
  I want to add a constraint to just shows three records per row.</p>