QTextBrowser - Heading H6 does not resize

QTextBrowser does not resize heading H6 when zooming.

This bahavior was observed when using QOwnNotes v23.12.3 which uses QTextBrowser in the preview pane. The author of QOwnNotes confirmed that this must be an issue with QTextBrowser here:

• https://github.com/pbek/QOwnNotes/issues/2764#issuecomment-1868029672

Here's a screen recording showing the behavior:

• https://github.com/pbek/QOwnNotes/assets/6450056/60552ed0-3ba3-4707-830d-7ca450f83813

How to reproduce:

• Get QOwnNotes v23.12.3 for whichever platform you use: https://github.com/pbek/QOwnNotes/releases/tag/v23.12.3
• Start it up, you'll have a markdown cheat sheet / tutorial with up to H6 inside it.
• CTRL + Scroll in the markdown preview pane to resize headings.
• ^ Observe that all headings up to H6 resizes.