SparklingAir Scirra has already hinted in another thread that we will be able to color code and change pretty much anything we want to in the editor using CSS.
This is one of the few things CSS probably wont be able to fix. CSS is flexible, but it lacks the dynamic nature required to make something like the above request work from a stylesheet alone.
You'd need to be able to assign IDs and classes to HTML within the editor for it to work, which is definitely possible, but stretching C3 a bit.
Tangentially; 
Ashley 
Tom - the icons are SVG, are these styled within SVG object itself or the stylesheet? I hope it's the latter, I cannot wait to dig around C3!
I'm also praying for SVG support for our games.