I have just finished upgrading the default-styles / customising architecture; including updates of all 10 customisations we currently maintain.
It should noe be much easier for a site manager to maintain customisations of knotes default styling. I have broken down the default style into typography+main-layout versus a knotesCustom.css file which need only contain a few selectors. That file is included in the main default css dtml file by a dtml var include, so there is no extra header round-trip burden to support this factoring.
I've tested it by updating all 10 of the customisations we currently support in our own sites :o(