Removing unused styles in normalize

Hi, I've been trying to get a working setup that removes all unused CSS from normalize. All of the tools out there fail to parse the normalize.min.css file. So for I tried:

- **PurgeCSS** - Removes all of normalize
- **DropCSS** - Hangs forever (?)
- **PurifyCSS** - Removes nothing
- **UnCSS** - Removes nothing

I assume it's the ":where" selector that they all struggle to understand but I honestly don't know. Is it a limitation of the tools or am I just dumb? I really like how "postcss-jit-props" plugin is included in the documentation and it would be awesome to get a section about dead code elimination too!

I know the file is small as it is but all that dead code in my production bundles makes me lose sleep at night (yes, I might be a little bit obsessed with performance 😁).

Anyway, love this project and thank you for your work .

Start by reproducing the reported behavior with normalize.min.css using PurgeCSS, DropCSS, PurifyCSS, and UnCSS, paying particular attention to the :where selector and the existing postcss-jit-props documentation. Done should mean explaining the limitation or configuration needed and adding a documentation section describing a supported dead-code-elimination workflow.

Written by the indexing model from the issue text.