title: HTML/CSS: Flexbox not working
body: <p>Based on <a href="https://stackoverflow.com/a/20669539/7525350">this answer</a>, I wanted to implement sidenotes on a blog using a CSS flex box. I ended up with this HTML code:</p>
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-css lang-css prettyprint-override"><code>article {
    width: 66%;
  }
  
  aside {
    width: 33%;
  }
  
  .lfloat {
    flex: 1;
    float: left;
  }
  
  .rfloat {
    flex: 1;
    float: right;
  }
  
  .pwn {
    display: flex;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;section&gt;
    &lt;h3&gt;Lorem ipsum dolor&lt;/h3&gt;
  
    &lt;p&gt;
      Lorem ipsum dolor sit amet...
    &lt;/p&gt;
  
    &lt;p class="pwn"&gt;
      &lt;article class="lfloat"&gt;
        Lorem ipsum dolor sit amet...
      &lt;/article&gt;
  
      &lt;aside class="rfloat"&gt;
        This is just a small comment
      &lt;/aside&gt;
    &lt;/p&gt;
  
    &lt;p&gt;
      Lorem ipsum dolor sit amet...
    &lt;/p&gt;
  &lt;/section&gt;</code></pre>
  </div>
  </div>
  </p>
  <p>Instead of getting a sidenote with the same height, <a href="https://ibb.co/cyTwrv" rel="nofollow noreferrer">safari</a> begins the next paragraph directly under the sidenote, adjacent to the other paragraph. <a href="https://ibb.co/fdBGrv" rel="nofollow noreferrer">Vivaldi</a> does even quirkier by moving the &quot;L&quot; before sidenote and resuming the next line with &quot;orem ipsum...&quot;.
  (Links are pictures of the rendered output by both browsers)</p>
  <p>Questions:</p>
  <ul>
  <li>Is my code bad or is the feature implementation of the browsers causing me this issue?</li>
  <li>How could I fix the issue, so that it renders robustly at least on FF, Safari and anything built on top of chromium?</li>
  </ul>