Themes
Restyle the whole editor.
A theme can change the palette, sizes, the toolkit's widgets, the class icons and a few effects. Default, Light and High contrast are built in.
Installing one
Themes live in the config folder, one folder each:
~/.config/rbx-native/themes/<id>/
~/.config/rbx-native/appearance.json {"theme": "<id>"}
Put the folder in themes/ and name it in appearance.json, "default" goes back to Default. The editor picks it up within a second, no restart.
Writing one
A theme only has to name what it changes, everything else comes from Default. The editor re-applies the active theme whenever one of its files is saved, so you can write it with the editor open. THEMES.md has the folder layout, the manifest and every token.