Fix tag CSS; missing tag-0, duplicates for tag-2

I noticed there was no CSS style for tag-0. Also, there were two CSS definitions for tag-2.

(My tags still don't seem to be sorted correctly, but maybe I'll address that in another issue. For example, I have 3 tags in one "step size", but they appear out of order. I'm not sure what tags|sort is supposed to produce though.)