[Request] Add ability to set widget background color and opacity

[ghost]

This is an optional function, but for visual satisfaction it would be nice to configure at least the transparency of the widget background. Accordingly when changing the background you should also add the ability to change the color of text (white for dark background and black for light).

[dellasorte]

yep. it would be great to change widget colors

[nvllsvm]

Dupe of #20

[ioogithub]

I really need this as well. This widget gets a coveted place on my home screen however I have a 100% dark theme phone. This is the only piece of critical software that I cannot change the bright white background to a dark shade.

Please include a preset dark mode version of the widget or else allow the user to change the colors.