Close hamburger menu when a link inside of it is clicked

Following problem:
When you click on the sandwich/hamburger menu icon,a menu is opened. That works already.
What I am trying to achieve now is when you click on a menu item, the whole menu should close and reveal the site in the background.
The links load into a div via a script, so you won’t be leaving the actual site.

Important: this whole sandwich menu is done with a checkbox .. I tried copying some premade scripts that uncheck it but it just won’t work. Help would be appreciated.

komic.biz/new1.html <- Site