Override the style of the tl_popupSC5 popup

I am trying to override the styles of the popup so that it shows up in the correct place. Please let me know what is the correct way to override the styles

I tried adding a css for div id tl_popupSC5 like below but that does not work.

			<style type="text/css">
			#tl_popupSC5 {
				position: fixed;
			}
			</style>