Improve how whitespace & line height is handled in the stylesheets

[hugovk]

The vertical alignment of "Editors" inside its box is a bit off, it's too high up: https://docs.python.org/3/whatsnew/3.14.html

This is a <dl><dt>Editors</dt><dd>...</dd> structure.

We should also check other uses of this HTML in the docs.

[StanFromIreland]

I recall seeing this some time ago, yet today I cannot reproduce:

[pradyunsg]

I can reproduce this on Firefox on Android. The misalignment might be OS/browser specific.

[hugovk]

I can repro on Chrome/Safari/Firefox/Opera on macOS and Chrome on Android.

[StanFromIreland]

Yes I can reproduce with Safari on iOS but not with Firefox on Linux.

[pradyunsg]

The reason this is happening is #160 changed the line-height for p tags, but not dt. I'm guessing the classic theme has the same problem.

I've filed #303 with a targeted fix for this.

Separately, I do feel like it would be better to have a consistent line-height across the page, instead of only in specific elements -- by overriding what is being set by classic.css, and tweaking how we're placing whitespace (padding/margin) around various elements.

[hugovk]

I think #303 is good, thanks for that!

A more general fix, here or in Sphinx's classic theme, also welcome later. Can keep this issue open for that? Or a new one?

[pradyunsg]

Let's keep this open.