<!DOCTYPE HTML>
<title> absolutely positioned element should be vertically centered even if the height is bigger than that of the containing block (reference) - bug 812899</title>
<style>
body > div {
    font-size: 16px;
    position: relative;
    border: red solid;
    margin-top: 5em;
    width: 5em;
    height: 5em;
}

body > div > div {
    position: absolute;
    border: medium solid blue;
    margin: -23px auto;
    height: 150%;
    width: 150%;
    left: 0px;
    right: 0px;
    top: 0px;
    bottom: 0px;
}
</style>

<body>
    <div>
        <div></div>
    </div>
</body>

</html>