css/css-contain/contain-layout-001.html

<!doctype html>
<html lang=en>
  <meta charset=utf-8>
  <title>CSS-contain test: layout containment on non-atomic inlines</title>
  <link rel="author" title="Florian Rivoal" href="https://florian.rivoal.net">
  <meta name=flags content="">
  <meta name=assert content="layout containment does not apply to non atomic inlines">
  <link rel="match" href="../reference/pass_if_pass_below.html">
  <link rel=help href="https://drafts.csswg.org/css-contain-1/#containment-layout">

<style>
#pa {
  contain: layout;
  height: 100vh; /*If layout containment applies, the span becomes a BFC, height applies, and knocks SS off the page */
}

#ss {
  vertical-align: bottom;
}
</style>

<p>Test passes if there is the word "PASS" below.</p>
<div><span id="pa">PA</span><span id="ss">SS</span></div>