Trouble w/ white background filling through nav menu

Hello,

I found the CSS code to make the post and header background white and display a textured/picture background on the sides, but for some reason, the fill stops at the post, leaves a small space between the post and navigation menu, then fills up towards the header. You can check out what I mean here: lovesixtyone.com. Any ideas on how to fix this?

Thanks so much!

Jena