<!DOCTYPE html> <html> <head> <style type="text/css"> #separator, #first-child { height: 20px; background-color: green; } #parent { margin-top: -10px; } #first-child { margin-top: 20px; } </style> </head> <body> <div id="separator"></div> <div id="parent"> <div id="first-child"></div> </div> </body> </html>
