Boxed mode not working

So ive selected box mode and it always worked. ive been working on the site a lot so im not to sure at which point it stopped. ??

I just suddenly realised that its spreading the white on the left and right side all the way.

https://controltrading.co.za/

I need the left and right sides of the bottom part of the site to be the same as the black background image.

Thanks in advance. ??