Feature request: external themes support

[andrej-urvantsev]

It would be nice to have a possibility to use AtlantaFX without any additional css modifications, but it seems that current themes are too opinionated (for example see "Files" header):

Maybe, if possible, it would be nice to not have customization in the docking framework itself, but rather just use defaults, so it can be customized more easily.

[Beowolve]

I see, will check this out as well, thx 4 the input