Unused CSS is an online tool to remove unused CSS rules. It will check your pages, find unused CSS and let you download a clean CSS file.
Simple to use website. Good if you're not a developer.Cons:
Too expensive. Does not work with React.
If you're a developer or know a developer there are better options such as: https://www.purgecss.comLouis Galipeau has used this product for one day.