[Theme: Twenty Fourteen] Removing space reserved for main navigation

Hi all, I’ve been modifying the twenty fourteen theme to turn it into pretty minimal website for a gallery, with a left orientated menu.

While I’ve managed to hide the primary navigation menu from view, for the life of me I can’t work out how to remove the horizontal bar of white space which it normally occupies.

An example page on the website is here: link

Ideally, I’d like for all the content to be moved upward to eliminate that white space at the top, so that the blue menu bar is kissing the top of the page.

Any help would be greatly appreciated!