I am very new to developing and just started with building a custom theme. I already registered a menu using the wp functions (register_nav_menus etc.) and am now trying to get my sub-menu to work.

What is the best way to build a responsive dropdown menu? I want to hide to whole menu “behind” a hamburger button and then open it if its clicked.

I know this is a pretty vague question but I am wondering if there is some javascript available for it somewhere or if its maybe possible to do with only css!

Thanks!!