To switch back to light mode, here's a quick guide:
Open View in the main menu of WiFi Guard.
Uncheck Dark Mode there.
Restart WiFi Guard by selecting File - Quit from its main menu. Avoid using the [X] button for closing the app, as this may send it to the notification area instead of exiting.
Once restarted, the application should appear in light mode.
I used the "Quit" drop-down field instead of the "X" button in the corner, and it works fine that way...
I want to use the dark mode because of my eye condition, but I can't do anything on the top bar with black letters on a black background... Let me know when you have fixed it...