Padre supports theme. How to change geany editors background colour. How to set up preferences or add themes to geany.
Geany themes (called, color schemes) are located in
You can add more schemes from this site. You'll want to copy from the
After all the .conf files are added, you can now choose a new color scheme from the menubar. Choose one that you like, and then edit its .conf file. In this file, under the section
[named colors] or
[named styles], you can change the background color to whatever you want. The colors are in RGB hex format.