how to remove header and nam meny on custom page

Hi,

Anyone that can give me an css code to remove header and nav menu?

the site can be found here https://www.pannekakeoppskrift.no

and the custom page where I want to remove header and nav menu is

https://www.pannekakeoppskrift.no/spill

I have added this code so far

.salesletter #header { padding: 0; border-bottom: 0em; }
.salesletter #footer { padding-bottom: 0; border-top: 0em; }
.salesletter #footer { display: none; }
.salesletter #sidebars { display: none; border: none; }
.salesletter #tabs {display:none;}
.salesletter #content_box { background:none; }
.salesletter .comments_closed { display: none; }
.salesletter #header #logo { display: none; }
.salesletter #header #tagline { display: none; }
.salesletter #content { margin: 0 auto; float: none; }

I have managed to remove sidebars and wigdets, but the nav menu and header is still visible.