Colours are configurable, see [the manual](https://www.geany.org/manual/current/index.html#customizing-geany-s-appearan...)
No info on that issue, except section "Customizing Geany's appearance using GTK+ CSS" [1] in which there are 8 IDs (geany-compiler-context, geany-compiler-error, geany-compiler-message, and etc.). So the question which IDs and classes should I use to change colors of the message window (comprising status, compiler, messages, scribble and terminal) and tree view for the files, If threre are some ?
For example, I can with ID #geany-compiler-message { color: #MyCustomColor; } change color of the text, but I can't the same way change background-color #geany-compiler-message { backround-color: #MyCustomColor; }. Is any way to change these colors, except by changing theme on OS ?
1. https://www.geany.org/manual/current/index.html#toc-entry-190