This is such a cool plugin for testing out Css changes easily.
I may not provide the completed solution you might desire, but I do try to provide honest suggestions to help you solve your issue.
my vote for best plugin created in 2014! great if you are working on a site with cloudflare, or other caching, that you can't disable easily.
Also for your suggestion - I actually have a HTMLedit plugin for default.master editing coming up.
My themes: pure | minusbaseline - My plugins: CSSedit | HTMLedit | InfiniteScroll | BirthdayModule | [all] - PM me about customizations
VanillaSkins.com - Plugins, Themes and Graphics for Vanillaforums OS