Graham Keyarn that css is fine but probably does not do what you want or you are putting it somewhere it gets over ridden
Do you mean 'mark active navigation item' ?
it depends on how the navigation is constructed
but if it is basically links in a <div> then xtgem has a built in system
all you have to do is have 'xtgem_template.css' with at least one class (even just a dummy one like .dummy {})
and then add xt_navigation class to the div
and the class 'active' is added to the active item (you set your styles in that class)
I also have a javascript that does the same thing
it all depends on your nav code which one you use
so which site is this on ?