[Pharo-project] Pharo Theming: does anyone have some doc?

I am digging inside the UITheme and friends and wondered if there was any documentation about it. Googled already but not much turned up. I've got some success in the PharoTheme (fill-style) category and now have a decent grasp of how it works (it is strange to find a ton of glamorous-xxx methods in the private category of PharoTheme but well). I want to do a high contrast/dark theme for my own work as it would be better for accessibility. I find the Darcula theme pretty neat (http://www.jetbrains.com/idea/) and use it for work. Would be lovely to have some close thing for Pharo. TIA Phil