Scrollbars shouldn't be in light mode

[deboer-tim]

Bug description

Since the PatternFly removal scrollbars are almost invisible because they're defaulting to light mode and render as black, and when you hover they go really light:

Screen.Recording.2023-11-20.at.12.22.59.PM.mov

I already proposed a possible fix via #4826, but #4887 is in this area as well.

Operating system

macOS 14.1

Installation Method

None

Version

next (development version)

Steps to reproduce

No response

Relevant log output

No response

Additional context

No response

[benoitf]

sorry @deboer-tim I didn't replied in the PR
yes I think we need to go with the color-scheme but as you proposed in a comment, it needs to be done conditionally (don't hardcode it to dark in the css file)

[deboer-tim]

Yes, the fix proposed in #4826 was purely 'quickest path to fix regression'. Now that we have #4887 we should do something dynamic instead.

Want me to do a PR based on my comment #4887 (review), or do you have a better idea?

[benoitf]

I'll provide a PR, I'll explore different solutions