how to remove a header of a page (not the homepage)

Replies: 0

I tried several suggestions to remove the header from a certain page without success.
I used:
.page-id-04 .site-header { display: none; }

or
.singular-page-id-40 .site-header {
display: none;
}
both via the plug in “Simple Custom CSS and JS”
but this doesn’t seems to work.
What do I wrong ?
(I’m using the free Pinnacle Kadence theme)