It's modified version of https://greasyfork.org/en/scripts/41-userstyles-org-css-highlighter (by trespassersW) for the new userstyles.org layout.
It uses the arrive.js library.

Thanks to trespassersW for a very useful script!

The script works and is tested on Tampermonkey and Violentmonkey.
Greasemonkey -any version- is not supported (the script might work, but is not tested).

If you have any bugs, bug fixes or ideas, please report at my GitHub repo