This is an electron application which lets you theme your Arduino IDE.

Install and run Arduino Theme Maker using following commands

git clone https://github.com/pro-nav/ArduinoThemeMaker.git
cd ArduinoThemeMaker
npm install
npm start

Once launched you can select the preview the availabe themes. To apply a theme press Apply button. This will create a dialog to select Save location. theme folder will be created at the selected location. Now, replace the orignal theme folder at Arduino/lib/theme with this newly created one.

If you get errors after selecting save location it is due to lack of Administrator permissions. Select another location like Documents or Downloads, etc. remaining process is the same.

If your Arduino IDE is not starting after applying the theme delete the theme folder at Arduino/lib/theme and now paste the new theme folder at the location. If still the problem persists, reinstall Arduino IDE and cerate an issue.