The colors for the theme is inspired from Debian.
This is WIP, maybe here you will find more information: MarlinFirmware/Marlin#12096
In the resources folder you find Sources.txt, where all resources used are listed.
Please make sure to only use FOSS compatible resources.
The software used to design the UI is DGUS_Setup_v5.1 and can be found here. http://www.ampdisplay.com/download1.php?cat=HMI%20UART(DWIN)&sub_cat=DGUS