It's time to take a closer look at the new fancy CSS Houdini that exposes a low-level API to the CSS engine. It will probably change the way we do styling in the future!
Your task is to take the given starter and use any of the examples shown in https://css-houdini.rocks. How that's done is up to you to find out! Maybe it's simple, maybe it's complicated, who knows?
If you have time left, try using multiple examples or try writing your own :)