CSS for widget of Recent global posts

Hi i have create page that i will use as advert of my site on other sites (widget)
http://ads.bettingtip.info/widget/

its made from recent global post widget, i use this code to place it anywhere i want
<iframe src="http://ads.bettingtip.info/widget/" border=0 frameborder=0 width=300 height=250 scrolling=yes></iframe>

Just tell me how to via CSS remove top space, i mean to remove on colour gray background of page,
see use of widget here http://default.bettingtip.info/ (right sidebar top widget)
its gray above and when scroll its also gray down, i want to remove top space and paint gray space down.

Thanks,