The logic of this package is based on taking :root or html in the absence of :root. And if there is no substitution of the standard value of 16 pixels. Taking the font-size value from root.
After that, the logic of finding all the values in pixels in the css document is used and replacing using the calculation.
If you have a suggestion or a better implementation of find and replace values. You can submit a PR for review. Or write to me personally about your idea.