suggestion: improvements to battery status detection

Due to power line may be loose coupled or unstable, unplug and replug may happen frequently when device is shifted. In this situation, when "enable dark mode when device is unplugged" is enabled, dark mode would be toggled again and again. So I suggest adding a delay time (like 10 seconds or user defined time) instead of switching to dark mode immediately when device is unplugged (and light mode when back to plugged).