How to remove menu from all pages

Hi there,

I read through the forums, tried what I found and I didn’t get a result.

It says in several threads to add this to the custom CSS:

#header_main_alternate { display: none; }
#advanced_menu_toggle { display: none !important; }

However I’ve added it and nothing changes.

Can you help out, please.

I want to completely remove the menu from both desktop and mobile version of the website.