<!DOCTYPE html> <!-- webkit-test-runner [ LayoutFormattingContextEnabled=true LayoutFormattingContextIntegrationEnabled=false ] -->
<style>
center {
    width: 100px;
    background-color: blue;
}

div {
    width: 50px;
    height: 50px;
    background-color: green;
}
</style>
<center><div></div></center>
<center><div style="margin-left: 50px;"></div></center>
<center><div style="margin-right: 50px;"></div></center>
<center><div style="display: table;"></div></center>