title: CSS3 column-count property is not working
body: <p>I'm trying to split a list into multiple columns once one exceeds the parent's (<code>ul</code>) height and I'm trying to do so with the <code>column-count</code> property but it doesn't seem to be working as the list is still condensed on a single column.</p>
  
  <p>The heights of the <code>li</code>s are dynamic. When they exceed the height of the <code>ul</code> they just get squished on the same column but I want them to move to a second column.</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>ul {
      max-width: 1180px;
      display: flex;
      justify-content: flex-start;
      flex-direction: column;
      -moz-column-count: 3;
      -webkit-column-count: 3;
      column-count: 3;
      margin: auto;
      padding: 0;
      max-height: 300px;
      width: 95%;
  }
  li {
      display: flex;
      flex-direction: column;
      float: left;
      height: auto !important;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;ul&gt;
   &lt;li&gt;1&lt;/li&gt;
   &lt;li&gt;2&lt;/li&gt;
   &lt;li&gt;3&lt;/li&gt;
   &lt;li&gt;4&lt;/li&gt;
   &lt;li&gt;5&lt;/li&gt;
   &lt;li&gt;6&lt;/li&gt;
   &lt;li&gt;7&lt;/li&gt;
  &lt;/ul&gt;</code></pre>
  </div>
  </div>
  </p>