How To Remove Space Between Nav Bar & Content Box

Hi,

I’m hoping someone out there can help me remove the space that I have between the bottom of my navigation bar, and the top of my content box.

After looking @ my page in Firebug, the area is :

DIV#post-93.post_box.top

My preview page is : https://www.thereadersden.com/wordpress/?page_id=93

Any help is appreciated !