[custom scrollbar]

…So im sorry if this is in the wrong place.

Hello;
I was wondering if any of you knew how to create a scroll bar that isnt the default one…
I have been told that it can be done through CSS (WTF?) but they didnt explain it very well…
I would like it so that the scroll bar is just a rectangle filled white. With a one pixel stroke of the colour gray.
Can anyone help?