How to configure the font for messages in the right gutter?

[pmonks]

I’ve configured Sublime Text 4 (build 4192, macOS) with a custom font (Source Code Pro for Powerline), but for some reason messages in the right gutter (e.g. output from evaluating code in an attached REPL) show up in a Serif font of some sort:

I’ve grepped through all of my custom .sublime-settings files, and I can only find the one font-face property configured, in $USER/Preferences.sublime-settings, and it’s set correctly (confirmed by changing it, and seeing the main editor font change).

Is there some alternative property I also need to configure to get these right gutter messages to use my preferred font? If so, what is it? If not, what might be causing Sublime Text to ignore the configured default font?

I’ve also noticed that hovertips are also using the same Serif font as the right gutter - possibly related?

[bschaaf]

That’s being drawn using the font defined in the theme. You can either customize a theme to use your desired font, or alternatively you can tell the annotations to use a specific font (annotations are html).

[pmonks]

Apologies for asking a LMGTFY type question, but how does one go about customizing a theme? I did search first, but didn’t find much in the way of beginner-friendly, step-by-step instructions.

[deathaxe]

To the best of my knowledge popups, phantoms and annotations use font_face setting set for editor control by default.

Those being rendered with Serif font already indicates a package providing custom CSS rules to attempt to change fonts, but eighter specifying a font not installed or providing incomplete CSS causing ST issues to merge its rules with global defaults. FWIW, ST is not good at merging multiple CSS for minihtml. So even valid adjustments can cause this effect/bug. Once hit by it, the only way to fix it is finding and removing the package causing it. Any other attempt to adjust those fonts in additional CSS rules is of no success.