Full Width Posts Page/ Shop Page

Hello! I’d like to make my posts page into a full-width page. Currently the posts page is scrunching the header/navigation bar and it doesn’t look as aesthetically pleasing as I’d like. The rest of the pages are fine in which the header is extended fully so that all the pages are still side by side. It’s only the posts page and the shop page where they get scrunched and the cart page ends up under the rest of the pages on it’s own.

Any help is greatly appreciated!

The page I need help with: [log in to see the link]