Background not behind the product grid ?

Hi.
I just made my own theme and i need the productgrid to be on a page and i pasted the shortcode in to the content area but when i look at the page my background color is not behind all the content.

it is like the grid is only a

and not inside a <div> so it dosent fill the area.

it could be my theme that is the problem but i cant seem to solve it on my own?

any suggestions to what the problem might be?

link to the page so you can see it fore your self: LINK