Ready program written in C #.
The idea of the program is an inventory system, it is a form screen, and each screen has a design.
The required: Modification of the form and design of the form, for example, the background of the form is black (Dark) when trying to change it from the properties or code. No results.

Also, when adding an image in the background, it does not appear when running the program and the program's interface remains in black, knowing that it is a metroform user.