<!DOCTYPE html>
<style>
#backdrop {
    position: absolute;
    top: 100px;
    left: 100px;
    height: 100px;
    width: 100px;
    background: green;
}
</style>
<body>
Test that ::backdrop does not inherit from anything. The test passes if there is
a green box and no red.
<div id="backdrop"></div>
</body>
