What products do you offer that only allow for CSS qualified values?
When designing for the web, there should be an option that will only allow the designer to use CSS qualified values.
Sketch is a product that is taking off in the world of UX because of this great idea, and convenient implementation of saving design elements.
But Sketch is a product that doesn't work well with the Adobe suite, and is only available for Mac. So developers are left having to increase collaboration, requesting more work from UX to define specs, etc.
Please, please, please provide a product that solves this problem. Parfait is a good start, but lacks due to its web integration.
If I understand you correctly, what you're asking for would require a design tool (Photoshop, etc) to restrict feature usage and only permit creating designs that are expressible in CSS.
I understand the desire behind your question, and we've wondered about this too. In our experience, this idea has tested poorly among designers in the past. I think a more useful approach may be to provide information to the designer as they work, which alerts them when the choices they're making will create problems for implementation in CSS (or whatever their target is). This is something we're considering for the future.
Parfait is not attempting to solve this problem. Parfait is meant to aid in the translation from design to code.