Hiding Menu at different screen size

Hi,

The page http://parracatholic.org/cyp-home has a menu which I'd like to disappear into the hamburger menu once the menu item 'home' is close to hitting the logo on the left hand side. What kind of code do I need to be able to tell the menu to disappear at that point? At the moment it disappears but only when the menu goes underneath the logo.

Thanks!