title: Css–selector for when a html-document is inside an iframe?
body: <p>I'm trying to make a css-selector that assigns diffrent properites based on weather the html is inside an iframe or not. I tried this:</p>
  
  <pre><code>html:not(:root) body {
      background: black !important;
  }
  </code></pre>
  
  <p>I expect this to apply <code>background: black;</code> to the body if it's inside an iframe, but it doesn't, why? And are there any css options? I could always check with javascript if html is root.</p>
  
  <p>IE8 support not requierd.</p>