What is the problem?

From T322337#8406969:

In T322337#8406969, @Zdzislaw wrote:

After the change introduced here, the preview (in the vector-2022 skin) reverted to the standard font size in the main space,
but on Wikisource in the "Page" NS it made that (in the preview) unfortunately the font size is too small(!) (
(left view; right: preview):

https://pl.wikisource.org/w/index.php?title=Page:Wac%C5%82aw_Niezabitowski_-_Ostatni_na_ziemi.djvu/66&action=submit

much smaller than before the font enlargement that this change was supposed to eliminate :(

This makes it very difficult to work on WS

I think the problem is it has two nested <div class="mw-parser-output">, which means font-size: 0.875em is applied twice.

I wonder if this bug affects other extensions or features?

Steps to reproduce problem

1. Go to https://pl.wikisource.org/w/index.php?title=Page:Wac%C5%82aw_Niezabitowski_-_Ostatni_na_ziemi.djvu/66&action=edit
2. Click "Pokaż podgląd"
3. Look at the font size of the preview text

Expected behavior: It should be 14px (if your browser is at 100% zoom and 16px default font size)
Observed behavior: It is 12.25px

You can also reproduce this on beta, e.g. https://en.wikisource.beta.wmflabs.org/w/index.php?title=Page:War_and_Peace.djvu/30&action=edit

Environment

Wiki(s): https://pl.wikisource.org Wektor 1.0.0 (8c48541) 02:19, 15 lis 2022. ProofreadPage – (ff8fc3b) 08:11, 14 lis 2022.