<!DOCTYPE html>
<title>Flex painting order with z-index</title>
<link rel="author" title="Martin Robinson" href="mailto:mrobinson@igalia.com">
<link rel="help" href="https://drafts.csswg.org/css-flexbox/#painting">
<meta name="assert"
  content="z-index works on flex items even though they do not have `position: relative`" />
<link rel="match" href="../reference/ref-filled-green-100px-square.xht">

<style>
    #flex {
        display: flex;
        width: 100px;
        height: 100px;
    }

    #flex > div