Apply CSS to Iframe Content

[MUHJZOR]

I have used below code This is my Iframe:\[code\]<iframe scrolling='no' frameborder='1' id='fblike' src='http://www.facebook.com/plugins/like.php?href=http%3A%2F%2Fwww.XYZ.com%2F&send=false&layout=standard&width=450&show_faces=true&font&colorscheme=light&action=like&height=50'></iframe>$('#fblike').contents().find('.pluginButton').css({'background','#FF8000'});\[/code\]I have also applied Css directly \[code\].pluginButton { background: none repeat scroll 0 0 #FF8000 !important;}\[/code\]Still it is not working.I want to change pluginButton's background.I want to apply image to its background.How to apply?