serenity/Base/res/html/misc/margin-collapse-4.html

<style>
#foo {
    background-color: red;
    width: 100px;
}
#bar {
    background-color: green;
    width: 50px;
    height: 50px;
    margin-top: -50px;
}
#baz {
    background-color: blue;
    width: 50px;
    height: 50px;
    margin-bottom: 100px;
}
</style>
<div id=foo><div id=baz></div></div>
<div id=bar></div>