I think this is caused by the display bug I described in T341944#9129037. Marking as a subtask.

Ideally the fix should be applied in Vector (and also separately in Minerva and any other skins you need to support) – the styles should be added to skinStyles/mediawiki.page.ready.less as skinStyle overrides.

See https://gerrit.wikimedia.org/r/c/mediawiki/skins/Vector/+/952950 for an example of how to do this. I just don't know the full set of body styles that are expected. I'd recommend coordinating with Web to ensure that the correct body text styles from the skins can be inherited in this new location.

In T345308#9134218, @egardner wrote:

Ideally the fix should be applied in Vector (and also separately in Minerva and any other skins you need to support) – the styles should be added to skinStyles/mediawiki.page.ready.less as skinStyle overrides.

See https://gerrit.wikimedia.org/r/c/mediawiki/skins/Vector/+/952950 for an example of how to do this. I just don't know the full set of body styles that are expected. I'd recommend coordinating with Web to ensure that the correct body text styles from the skins can be inherited in this new location.

Filed T347199. One minor issue to workaround is the default body padding in Codex's dialog will probably create an undesired extra vertical gutter above headings inside the dialog body. It would be nice to be able to configure the dialog body gutter somehow. Ideas welcome.

Change 961750 had a related patch set uploaded (by Sergio Gimeno; author: Sergio Gimeno):

[mediawiki/extensions/GrowthExperiments@master] Personalized praise: avoid extra top gutter in settings form

https://gerrit.wikimedia.org/r/961750

Change 961750 merged by jenkins-bot:

[mediawiki/extensions/GrowthExperiments@master] Personalized praise: avoid extra top gutter in settings form

https://gerrit.wikimedia.org/r/961750