The application got a big update: a few new rules for solitaires had been implemented and the number of solitaires out of the box increased from 7 to 26 solitaires out of the box. Other changes:
- Added detailed info about the selected pile (sort orders, the number of cards in the pile etc, so you do not have to learn how to play by experimenting)
- Added time tracking: now the application knows how much time you spent on each solitaire and displays it in the solitaire selection dialog
- New CLI option
--four-colorto use 4 distinct colors for suits instead two colors (though, maybe the color selection may be better - any idea is welcome) - Fixed a few bugs
Here solkit look with --four-color option passed:

Thank you!
Edit: sorry, I forgot to include the link to the sources
Here it is https://github.com/VladimirMarkelov/solkit