Can Safari do this?

I noticed that in Firefox you could change the color of text or backgrounds, which I find really useful because there's some sites that I'm frequenting, but their layout is way too dark. I like a bright theme!

Is this possible with Safari too in any way? I looked around the settings but couldn't find anything. I'd like to apply it only to a few sites. Maybe there's a piece of code somewhere in the Safari files, that I could edit? I have some programming skills, so who knows 🙂