I was just trying to help fix the CSS, and I think I've done that.

If we're reconsidering the behavior of the nav sidebar, then I'd like to point out that if you're far down the page, the sidebar is blank to your right. From a usability point of view, it's already broken. It was a neat idea, but a ToC for the page would serve the purpose better.

My monitor is quite large, and rotated 90 degrees, so it's narrow and tall. A web-page can be infinitely long, but its practical width is limited to the user's screen, which is different for every user. That's why HTML was designed the way it is, with auto-word-wrap.

When you have a bunch of stuff that you want to fit within a window, a sidebar makes more sense. For Python docs, I'd vote to drop it altogether, as attractive-looking as it is.

But if you really want it, give it its own vertical scrollbar, so that a relevant portion is always visible. Then people can talk about dynamic controls.

That's just my opinion. I created this bug because, when I zoon, the sidebar consumes most of my screen with no visible text. It's such a huge problem that I was afraid someone had already submitted this.