css/css-scroll-snap/scroll-snap-root-003.html

<!DOCTYPE html>
<html>
<title>scroll-snap-type does not propagate body to viewport</title>
<link rel='author' title='Elika J. Etemad' href='http://fantasai.inkedblade.net/contact'>
<link rel='help' href='https://drafts.csswg.org/css-scroll-snap-1/#scroll-snap-type'>
<link rel='help' href='https://drafts.csswg.org/css-scroll-snap-1/#scroll-padding'>
<link rel='match' href='no-red-ref.html'>
<meta name='assert'
      content="Test passes if scroll-snap-type on body is not applied to viewport.">

<style type='text/css'>
:root {
  overflow: hidden; /* hide scrollbars for reftest analysis */
}

body {
  scroll-snap-type: block mandatory;
}

#pass {
  height: 120vh;
}

#target {
  scroll-snap-align: start;
  height: 100vh;
  background: red;
}
</style>

<p id="pass">Test passes if there is no red.

<div id="target">
  <div>FAIL</div>
</div>