User JavaScript and CSS VS Greasy Fork

You can use such scripts on tampermonkey (chrome) or greasemonkey (for firefox) or User Javascript an CSS injector. Source: 10 months ago

Speaking of Kbin, I made a blue theme (before) that anyone can use. Here is the CSS code. To apply it, use the chrome/brave extension called 'User JavaScript and CSS'. There are other extensions in different browsers that do the same thing, just search for custom CSS and apply the css code to kbin.social. Source: 11 months ago

I recommend this to use it: https://chrome.google.com/webstore/detail/user-javascript-and-css/nbhcbdghjpllgmfilhnhkllmkecfmpld. Source: about 1 year ago

Goto https://chrome.google.com/webstore/detail/user-javascript-and-css/nbhcbdghjpllgmfilhnhkllmkecfmpld, click "add to Opera" and click "add extension" to install it. Source: over 1 year ago

You might be able to use this extension to apply CSS that specifies a background image to sites you want. Source: over 1 year ago

Have tampermonkey installed (google), then go to greasyfork (website) I have the link here https://greasyfork.org/en and search up character ai, have fun :)). Source: 11 months ago

If the above mentioned URL rewriter doesn't work for you (I found it hard to use myself, and never could get the rules figured out), then you could try using https://github.com/janekptacijarabaci/greasemonkey and finding a redirect script here: https://greasyfork.org/en. Source: 11 months ago

I was thinking more greasemonkey / userscripts. Source: 12 months ago

Https://greasyfork.org/en is sort of what you're looking for. - Source: Hacker News / about 1 year ago

Then you should rather look for simple userscripts on for example https://greasyfork.org/en then use them or convert to uBO scriptlet syntax (which should be easy). Source: over 1 year ago