<!doctype html>
<html lang=en>
  <meta charset=utf-8>
  <title>CSS-contain test referemce</title>
  <link rel="author" title="Florian Rivoal" href="https://florian.rivoal.net">

<style>
html, body, p, div {
    margin: 0;
    width: 200px;
    height: 200px;
}
</style>

<p>Test passes if there is no red.