<!doctype HTML>
<title>A filter on the root element applies to its background</title>
<link rel="author" title="Chris Harrelson" href="mailto:chrishtr@chromium.org">
<link rel="help" href="https://drafts.fxtf.org/compositing/#pagebackdrop">
<html style="background: #FFF">
  <div style="width: 50px; height: 50px; background: #1CC"></div>
  <div id=spacer style="width: 100px; height: 3000px"></div>
</html>