To create a theme currently: get the oojs/ui repo, copy-paste the src/themes/blank directory to your own name, list the new theme in Gruntfile.js and maybe a few other places (i could find them all if you're serious about doing this), and start writing the CSS

I want a more modular approach, where themes are definable in any extension, and consist of an array of variables in json or less or something which OOUI then assembles that into the css/js itself:

• A set of colours for different things (borders, backgrounds, text, different types of buttons, etc)
• General properties - how much spacing in general, whether to even use any shadows, whether buttons should be gradiented or flat, whether to override fonts, that sort of thing
• Specific properties for all the types of things (buttons, dialogs, inputs, etc) such as rounded corners, gradients, shadows, fonts, padding - none, or specific values (what sort of gradient, what sort of shadow, how much padding)
• ...
• Profit?