UI improvements

[julianfairfax]

Apart from the whole German-only thing, this app is working pretty well for me. There are however a few UI things that I think should be improved for a better experience:

• The app icon isn't adaptive. You can see this by looking at the app info page, where the icon will be surrounded by a white background
• The green accent colour of the app is a little out of place on my device. I think maybe the blue used in the icon would be a nicer fit? Maybe Material You is possible?
• Dark mode doesn't follow the system theme (#36)

Otherwise, this app is pretty nice. I can now get Alertswiss alerts without GMS, which is a big win for my open source use case!

[nucleus-ffm]

The color theme thing is prepared here, what is still missing is the implementation of how to switch between them. I want to update the app icon soon. But for that I still need a good idea how the icon should look like. With the new icon, I would also figure out how to have an adaptive icon. The last point is already done. Maybe i can implement the color thing next Spring. Is this really something that keeps you from using the app?