css/css-contain/contain-body-bg-002.html

<!doctype html>
<html lang=en>
  <meta charset=utf-8>
  <title>CSS-contain test: paint containment on body prevents background propagation</title>
  <link rel="author" title="Florian Rivoal" href="https://florian.rivoal.net">
  <meta name=flags content="">
  <meta name=assert content="paint containment on body prevents background propagation">
  <link rel="match" href="reference/contain-body-bg-001-ref.html">
  <link rel=help href="https://drafts.csswg.org/css-contain-1/#contain-property">

<style>
html, body, p {
    margin: 0;
    width: 300px;
    height: 200px;
}
p {
    background: white;
}
body {
    background: red;
    contain: paint;
}
</style>

<p>Test passes if there is no red.