On Chromium-based browsers, workboard columns such as https://we.phorge.it/project/view/105/ have customized thin scrollbars:

On Firefox, however, they have the default OS scrollbars:

This is because they are defined using non-standard CSS pseudoelements ::-webkit-scrollbar and ::-webkit-scrollbar-thumb.

The default scrollbars can get really unsightly on large workboards, such as https://phabricator.wikimedia.org/project/view/4864/:

Firefox supports the standard scrollbar-width: thin CSS property that can be used to achieve a similar effect: https://caniuse.com/mdn-css_properties_scrollbar-width

It would look like this:

(None of this applies if your OS does not display static scrollbars. macOS and many Linux environments only display overlay scrollbars by default.)

Other examples

Examples in GNU/Linux with KDE, on hover:

Before	After

Examples in GNU/Linux with KDE, on bar selected:

Before	After

[This is a follow-up task for Q63.]