Yes, I have had this problem as an on-going problem, often the solutions are out there but they solutions assume we Webflow designers no how to insert the code, which quite often we don’t, hence why we use Webflow!
I am slowly getting the hang of things via a painful learning curve.
In this instance, you can add this to your site head code area (in the setting panel under custom code), you need to add all code that is targeting a class style by inserting it inside opening and closing style tags, see here…