>>24105
It's defined in https://boards.guro.cx/static/css/kokoimg/base.css
Unless you use an ancient browser, styling should appear without the need of JS.
If you use an ancient browser, then JS is effectively "required" for some CSS: https://jhildenbiddle.github.io/css-vars-ponyfill/#/ - in short, we are using a backwards-compability script and there is simply no other good way of doing this.

If you want to keep to use an ancient browser, have JS disabled on GUROchan, and want to see the right CSS, you have two choices:
- executing ponyfill via some browser extension
- giving them var-less styling via some browser extension

Besides this, all JS are merely QOL improvements (though most wouldn't work on old browser anyways) and you can simply inspect the source code before individually allowing them if you have doubts about privacy.