css/css-contain/contain-size-button-001.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>CSS Containment Test: Size containment on button</title>
<link rel="author" title="Manuel Rego Casasnovas" href="mailto:rego@igalia.com">
<link rel="help" href="https://drafts.csswg.org/css-contain-1/#containment-size">
<link rel="match" href="reference/contain-size-button-001-ref.html">
<meta name=assert content="Size containment does apply to buttons, thus their size is the same than if they don't have contents.">
<style>
button {
  border: 5px solid green;
  padding: 0;
  margin: 0;
  contain: size;
  color: transparent;
  font-size: 2em;
}
</style>

<p>This test passes if it has the same output as the reference. You see the word "before", a 10px green square at the top, and then the word "after".</p>
before<button>flex</button>after