Help with native scrollbars plugin

Hello everyone,
I can’t figure how to enable native scrollbars on obsidian.
The standard one look really bad with my theme.
So, I tried to use the “native scrollbar” plugin, but it doesn’t seem to work
Is there anything I am missing ? Is there a css snippet that could do the job ?
I’m sorry if it’s obvious, I’m a beginner.…

I am using obsidian v.1.1.16, with native scrollbars v.1.0.1

Here is a video demonstrating the problem :