About ::-webkit-scrollbar and similar selectors

HTML-CSS
1

Do the styles for the ::-webkit-scrollbar and similar selectors not work in particular browsers like Firefox?

I’m currently following this tutorial: https://www.youtube.com/watch?v=Aj7HLsJenVg&t=29s

and when I got to the scrollbar styles, the styles are not working on my browser.

I then looked at the mozilla web dev doc page and it turns out to be non-standard, which I’m not totally getting yet. I’m guessing this feature is outdated?

2

it means that not all browsers have implemented it, or they could have implemented it in a different way

it means it is not part of the standard specs, you should not use it