F.A.Q.

How about performance?

Generating CSS at runtime has performance costs, especially if your code is in a hot path (and usually with CSS-in-JS that's true for all your styles). However, the hit isn't more than using dynamic values in styled-components or using styled-system. We were also very restrictive about the shipped features to keep the core as primitive as possible. CCSS on its own avoiding a lot of processing other solutions have.

However, to boost performance YouEye has a Babel-plugin supporting static extraction. It replaces all Ui calls with native DOM elements and class names.

Why just not use styled-system?

It's not YouEye's goal to have an amount of features styled-system have. However, the mapping approach used by CCSS is making the compiler capable of supporting custom properties and custom values which helps you to create your own custom design system, ergo: Styled System could be implemented using CCSS.