chromium/third_party/blink/web_tests/external/wpt/css/css-flexbox/flexbox_quirks_body.html

<!doctype quirks><!-- Intentional quirks mode -->
<title>CSS Test: Flex body in quirks mode</title>
<link rel="author" title="Aleks Totic" href="[email protected]">
<link rel="help" href="https://www.w3.org/TR/css-flexbox-1/#main-sizing" title="9.3 Main Size Determination">
<link rel="help" href="https://quirks.spec.whatwg.org/#the-body-element-fills-the-html-element-quirk" title="The body element fills the html element quirk">
<link rel="match" href="./reference/flexbox_quirks_body-ref.html">
<style>
html {
  margin:3px 6px 9px 12px;
  padding: 0px;
  background-color: green;
}
body {
  display: flex;
  margin: 7px 11px 14px 23px;
  padding: 0px;
  background-color: yellow;
}
</style>
Flex body in quirks mode should fill viewport except for margins.