I want to custom-style a scrollbar with CSS.
I use this WebKit CSS code, which works well for Safari and Chrome:
There's no Firefox (Gecko) equivalent to
::-webkit-scrollbar and friends.
You'll have to stick with jQuery.
Plenty of people would like this feature, see: https://bugzilla.mozilla.org/show_bug.cgi?id=77790
This report is asking for the exact same thing you're asking for: https://bugzilla.mozilla.org/show_bug.cgi?id=547260
It was closed as a duplicate of the first report I linked to.