title: Flex align-items: center not centering items
body: <p>Flexbox <code>align-items: center;</code> is not working.</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;
    justify-content: center;
    align-self: center;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div class="container"&gt;
    &lt;p&gt;Lorem ipsum&lt;/p&gt;
  &lt;/div&gt;
  
  
      </code></pre>
  </div>
  </div>
  </p>