Hiding menu on one page

I am trying to hide the main navigation menu on a single page.

I’ve entered the following code on the custome css in the highend options general settings section:

.[pagename] #main-nav {
display: none;
}

It does not work.

It works when I isolate the home page with “.home #main-nav” or for the entire site with “#main-nav”
but I can’t turn off the main navigation menu for any other specific page.

is there different code I could use?

Thank you