Remove menu for one page

I am attempting to remove a menu on specific pages.

http://salonweb.io/courses/salon-web-free

This code works but it’s removing ot for the entire site. I only want to remove it for one page.

#floating_menu {

display: none;

}

I tried this but it’s not working… page ID 11 is a custom post type.

.page-id-11 #floating_menu{

display: none;

}

Any advise?