This tutorial shows you how to make your header span full width of the screen.
It also shows you how to make your nav menu’s span full width.
These solutions haven’t been tested on all 65+ StudioPress child themes however it has been tested on the AgentPress Pro child theme for a member of WP Sites.
Here’s the default header which only displays the width of the structural wrap.
Here’s the result after using one of the solutions in this post: