title: flex doesn't support calc in IE11
body: <p>I am attempting to create a layout using Flexbox. In one of these layouts, I want 3 equal width columns. To accomplish this I am using <a href="https://www.w3schools.com/cssref/func_calc.asp" rel="noreferrer">calc</a> to set the column width. This is working fine in modern browsers, but of course in IE it doesn't want to work. Here is my 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>.container {
    width:50vw;
    margin:0 auto;
    display:flex;
  }
    .container &gt; div {
      flex:1 0 calc(100% / 3);
    }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div class="container"&gt;
    &lt;div&gt;Test&lt;/div&gt;
    &lt;div&gt;Test&lt;/div&gt;
    &lt;div&gt;Test&lt;/div&gt;
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>As I mentioned, this works fine in modern browsers, but in IE the columns just collapse on each other unless I use a specific percentage in place of <code>calc</code>.</p>