title: Centering content horizontally using flexbox
body: <p>I'm struggling to center horizontally some content in my container:</p>
  
  <p><a href="https://jsfiddle.net/y56t31q9/6/" rel="noreferrer">https://jsfiddle.net/y56t31q9/6/</a></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>.container {
    display: flex;
    flex-direction: column;
    width: 600px;
    background-color: blue;
    justify-content: center;
    /* Not centering content horizontally? */
  }
  .item {
    max-width: 500px;
    height: 100px;
    background-color: yellow;
    border: 2px solid red;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div class="container"&gt;
    &lt;div class="item"&gt;&lt;/div&gt;
    &lt;section class="item"&gt;&lt;/section&gt;
    &lt;section class="item"&gt;&lt;/section&gt;
    &lt;footer class="item"&gt;&lt;/footer&gt;
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>I would have thought <em>justify-content</em> would have done the trick, but to no avail.</p>
  
  <p>Any help would be greatly appreciated
  Thanks!</p>