@garydavenport73 (and everybody else) don't edit system files!!!
It will be overwritten by a new release of Geany and you will lose your changes.
Create a `geany.css` in your user config directory (~/.config/geany by default on Linux, not sure where on Windows or Macos) and only put the things you want to override in it, its _Cascading_ Style sheets :-)
Or use `Tools->Configuration files->geany.css` and a version of the system file will be put in your user config wherever it is even on Windows or Macos. Just remember that if you do that the existing entries in the system files are overridden by the entries in this copy so changes with new versions won't be seen, so best to comment them out unless you specifically want to change them.