how to use default black background with popup?

Hi

Thanks for your replay. Can you help me with another problem which is very related to this.

please check the following link:
http://www.publiseek.com/test-page/

I am using popover with background-black. But it not working well. I have settings for popup at page-footer and I have to. It works with external page.

So can you please help me to sort out this problem.

Thanks