title: Text not centered with justify-content: center
body: <p>I've got a div with <code>display: flex</code>. Its content is centered horizontally and vertically.</p>
  
  <p>When content is too long in the div, the content wraps. But the alignment is broken in this case. See the snippet.</p>
  
  <p>If I add <code>text-align: center</code> it displays correctly. But why doesn't it center without <code>text-align: center</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>.box{
    width: 100px;
    height: 100px;
    background-color: lightgreen;
    margin: 10px;
  }
  
  .flex{
    display: flex;
    flex-direction: row;
    flex-wrap: wrap;
    align-items: center;
    justify-content: center;
  }
  
  .with-align{
    text-align: center;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div class="box flex"&gt;
    some long text here
  &lt;/div&gt;
  
  &lt;div class="box flex with-align"&gt;
    some long text here
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>