I was wondering how can i change the color from white to a black? Not talking about anything dealing with art, just the program itself.
Short answer: you cannot. There are no “themes” for the FireAlpaca interface.
However, MediBang Paint Pro, a sibling program to Firealpaca, has a dark interface. It is based on the same code, with most of the same painting features and using the same file format.
FireAlpaca has onion skin mode for animation, 3D perspective layers, and usually gets new features first. Probably better for screen-based output.
MediBang Paint has cloud-based (online) libraries of brushes and halftone textures, cloud-based multipage projects which can be shared with other users, and cloud-based brush sync between computers. It also has 64-bit versions which makes it better for large resolution print projects.