title: Flexbox leave one element above and two below without changing HTML
body: <p>I have simple divs like these:</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 {
    width: 20rem;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
  }
  
  .child {
    width: 50%;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div class="container"&gt;
    &lt;div class="child"&gt;1&lt;/div&gt;
    &lt;div class="child"&gt;2&lt;/div&gt;
    &lt;div class="child"&gt;3&lt;/div&gt;
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>
  <p>This makes it so that child 1 and child 2 are above, and child 3 is below centered. My question is, without changing the HTML structure, is there any way to make it so that the child 1 is above centered, and child 2 and child 3 are below?</p>