<!-- webkit-test-runner [ LayoutFormattingContextEnabled=true InlineFormattingContextIntegrationEnabled=false ] -->
<style>
div {
    position: relative;
    width: 50px;
    height: 50px;
}
</style>
<div style="background-color: green;"></div>
<div style="left: 50px; top: -50px; background-color: blue;"></div>