Add dark theme

[aha999]

• The dark theme/UI option is missing

[ligi]

this is a bit more complicated - the pictures must look good against a dark background - otherwise goot suggestion

[aha999]

The pictures could still be normal... or the edges of teas could be marked brighter to differenciate between dark UI and darker teas

[ligi]

would look really bad with the current images as they have white backgrounds.I have some images with transparency - wanted to do this anyway - just time constraints ;-)

[aha999]

Or replace the teas pictures with different colored cups/kettles (optionally from settings).

Or maybe a white picture could have rounded edges so it would look better in dark mode