I am trying to reduce the font size for speaker notes in Quarto's revealjs format. I posted this question on stackoverflow and received an answer, but I'm looking for a way to set the relative size globally. The problem with a css file is evidently that speaker notes don't use the document's css.
Yes as @technocrat is showing, speaker note are inserted in a template provided by RevealJS directly. There is no way to insert CSS file to this template as revealjs does not allow it.
See How can I change the speaker notes font-size permanently? · Issue #2824 · hakimel/reveal.js · GitHub
This would a feature request for Quarto to allow passing custom a css file to the speaker-view.html file. If possible... You can open one at GitHub - quarto-dev/quarto-cli: Open-source scientific and technical publishing system built on Pandoc.