Sidebar menu dropdown

[waynner]

Hello everyone, i created a website with prestashop, and i had some issue to apply a change to my theme. I have a drop down menu which the sub menu go over the other selection when my page is in phone view. I wish that menu, instead of flying over the menu, it push the other option down and take place inside the menu.

Here is the website's adress:

https://elis-green.com/fr/

 

And a refereces of what i would like:

https://www.w3schools.com/howto/howto_js_dropdown_sidenav.asp