css/css-backgrounds/background-margin-will-change-root.html

<!doctype HTML>
<title>Backgrounds on the root element should extend to cover the entire canvas in the presence of margin and will-change: transform</title>
<link rel="author" title="Philip Rogers" href="mailto:pdr@chromium.org">
<link rel="help" href="https://www.w3.org/TR/css-backgrounds-3/#root-background">
<link rel="match" href="background-margin-will-change-root-ref.html">
<style>
  html {
    background: linear-gradient(lightblue, yellow);
    height: 300px;
    margin: 50px;
    will-change: transform;
  }
</style>