PLEASE stop doing this thing where you hide the scroll bar when it's not being used, or make it invisible, or super thin and difficult to see. this post explains why. as an example of this...
this is a great post that I 100% agree with, and also as someone with Brain Problems I find myself looking at the scroll bar on web pages a lot for reassurance about how far through a particular long read I am, and hidden-by-default scroll bars are infuriating to me
Hiding UI elements that are "assumed to be there because they always are" only works for people with very high tech literacy. To someone who doesn't use computers every single day or hasn't been doing it since before they started hiding the scroll bars, the UI has now become completely opaque with no way for them to figure out that there is more to see on screen or how to see more of it
