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