wp seo by yoast, when active,breaks up my design estructure

Hi!

My site with wordpress is http://www.ofertia.net
I activated the plugin WP Seo by Yoast, it’s quite good and so far I think it works well, yet I have noticed that my store’s design breaks up a bit becauee I get all of the sudden a space at the top I didn’t have before. Please, could you have a look and tell me how I can fix this?

I’d appreciate it very much!!!