How to select the dark theme for the app?
To change the theme
1. Open the Bigin app on your Mac.
2. Click Bigin in the menu bar that runs along the top of the screen.
3. Select Preferences to open Settings in Bigin.
Under "General", you can find the title Appearance.
4. Click on "Appearance".
5. Select the dark theme from the three options available under "Theme".