CSS to eliminate content inset - York

Site URL: http://www.701architecture.ca/contact

I'm hoping for some help with custom CSS to make the "contact" layout page in the Jasper template match the full width of the rest of the site (i.e. eliminate the inset). Squarespace customer care has directed me here as they simply note that regular pages on this template max out at 1280px with no style tweaks.

Any help would be hugely appreciated.