title: CSS form:valid selector doesn't work in IE11
body: <p>This css doesn't work in internet explorer 11:</p>
  
  <pre><code>form:invalid {
    background-color: red;
  }
  </code></pre>
  
  <p><a href="https://jsfiddle.net/jsf2rLck/2/" rel="nofollow">Demonstration</a></p>
  
  <p>As you can see the forms are still gray in internet explorer 11 while they should be red and blue. Is there any way to fix this without using javascript?</p>
  
  <p><a href="https://developer.mozilla.org/en-US/docs/Web/CSS/%3Avalid" rel="nofollow">MDN</a> doesn't mention any problems with it in IE11.</p>