[OT] CSS help?

[Brian Astill]

I'm using CSS on a website - OK (ish).

I want to have the same - editable - menu on every page of the 
site, and have one menu file so one alteration would change the 
menu on every page.

I can't find any reference about "how to" do this.  It probably 
isn't a CSS issue anyway?  Can it be done, by some means or 
another?

Where would I find info like this?

TIA

-- 
Regards,
Brian