[grumblestumble]

I really like this approach, but I think the thing that is currently missing is preprocessor/build support. The primary use case for this would be large-scale web applications -- it's probably overkill for anything else. Unfortunately, for large apps, the performance hit of using ~= is unacceptable. However, most large apps use some kind of build system - grunt, gulp, make, etc, and writing a task to convert these into old-fashioned CSS class names as part of the build seems entirely doable.