gh-142927: Add scrollbar support to Tachyon HTML dark mode by Wulian233 · Pull Request #148118 · python/cpython

Testing on macOS, with Chrome 143, there's no difference. The scrollbars are already invisible: black on black with no outline. This PR doesn't change this.

Likewise on Safari 263, the scrollbars are black on black, but at least with a dark grey outline, so they're just about visible. This PR doesn't change this either.

On Firefox 149, this PR changes the scrollbars from light grey on black, to a darker grey on black. Both of these are better than Chrome and Safari, but I think it was better before.

If anything, we should be making the scrollbars [more] visible, not less.