<!doctype html> <html> <head> <style> button { position:relative; left:0px; top:0px; width: 200px; height:100px; border:none; background:#00ff00; -moz-appearance: none; border-radius: 0 !important; } div { position:absolute; left:0px; top:0px; width:50px; height:50px; background:#ff0000; } </style> </head> <body> <button><div></div></button> </body> </html>