Creating a Navigation made out of Fullscreen Buttons

Hi,

for a Client i try to Create an Mobile First design made out of Fullscreen Buttons. For the Pages we Build it by hand butwe have to inetegrate this for all Pages and Post with the WordPress Menü Functionality. At this moment i havent an Idea how to make this, i know that i can give every menu Value an CSS Class but i cant figure out how to make it work.

Best regrats

Matthias