How to style custom menu items using CSS?

[feathertail]

Okay ... I can style all the navmenu items using .module-navlinks ul li a, but I'm trying to only style one of them. Like, say, the last one on the right on becomeyourfursona, with the custom1 class, that was added using a custom layer.

I've tried .module-navlinks .custom1 ul li a and various other permutations, including just straight .custom1 a, but none of it works. (It doesn't work on the other, non-custom menu items, either.) Firebug doesn't even show the rules as having been overridden; they just aren't there.

Is this is something I need S2 for -- and if so, where I can find out how to do CSS using S2? Because I remember earlier I tried changing the names of the menu items, and it only worked for "Recent Entries" and didn't work for "Reading." I suspect that menu items that have been modded in some way using a custom layer can't be customized further using the front-end.