background shading on GridMarket theme

Hi,

How do I remove background shading on the two-column GridMarket theme?

The shading is distracting and provides a poor user experience. Check it out on my site:

http://neatgear.com/store/products/asus-dual-band-wireless-router-rt-ac66u/

Also, I need to narrow the left-sidebar to 170px

David Michaels