astroturf lets you write CSS in your JavaScript files without adding any runtime layer, and with your existing CSS processing pipeline.

• Zero runtime CSS-in-JS. Get many of the same benefits as CSS-in-JS, but without the loss of flexibility in requiring framework-specific CSS processing, and while keeping your CSS fully static with no runtime style parsing.
• Use your existing tools – Sass, PostCSS, Less – but still write your style definitions in your JavaScript files
• Whole component in the single file. Write CSS in a template literal, then use it as if it were in a separate file

Checkout the docs for examples and API details: https://4catalyzer.github.io/astroturf/