UPDATE: The new UI style is now available in app version 1.40 released on February 22, 2017.
Currently some of the screens in Dwarf Fortress Remote application use light colour scheme while some use dark DF colours. This is because initially I was going to use the system default UI, however on some screens the data needs to be colour-coded using DF colors which requires dark background, so these screens were made dark. Now I've unified UI throughout the application (except for the screens before you connect to a game for now).