<!DOCTYPE html> <html> <head> <style type="text/css"> #sibling1 { height: 20px; background-color: green; margin-bottom: 30px; } #sibling2 { height: 20px; background-color: green; } </style> </head> <body> <div id="sibling1"></div> <div id="sibling2"></div> </body> </html>
