My problem with CSS-in-JS is that I have big part of my app which is not react based. So I have to style slim/erb templates and react components in a coherent

My problem with CSS-in-JS is that I have big part of my app which is not react based. So I have to style slim/erb templates and react components in a coherent and manageable way. The current thing I use is reasonable css from rscss.io but I still have a feeling of "disconnection" between templates/components and css.