<!DOCTYPE html>
<meta charset="utf-8">
<title>CSS Containment Test: Layout 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-layout">
<link rel="help" href="https://drafts.csswg.org/css2/visudet.html#propdef-vertical-align">
<link rel="match" href="reference/contain-layout-button-001-ref.html">
<meta name=assert content="Layout containment does apply to buttons, thus their baseline is their margin-bottom edge.">
<style>
button {
  border: 5px solid green;
  padding: 0;
  /* We use a nonzero margin-bottom to be sure we're synthesizing a baseline
     from the margin-box rather than from the border-box: */
  margin-bottom: 2px;
  contain: layout;
  color: transparent;
  width: 0;
  height: 0;
}
</style>

<p>This test passes if it has the same output as the reference. You see the word "before", a 10px green square aligned 2px above the text's baseline, and then the word "after".</p>
before<button>b</button>after