Class Importer is a tiny little utility I pulled together that lets you import a list of CSS class names into the Webflow UI.
It was born from the need to import dozens of colour and spacing token classes where the styling was handled by external CSS, but the classes were needed inside the UI so they could be easily added to elements.
It doesn't handle style rules themselves - although it could be extended to do so.
(I was reminded about this utility that I built by a recent Twitter post by Matt Evans about a tool called Markflow. It looks like Markflow does something similar - but imports the style rules for a single class only)