Sorry none of our themes are in active development right now. And are not tested on distributions above 16.04 LTS. They May not work on distributions newer then 2016.
GTK Themes (16.04 LTS, Mint 18 And Bellow Only):
Any theme listed as legacy is NOT Supported anymore.
Legacy themes can still be downloaded and used on supported systems. (Ubuntu 16.04 LTS, Mint 18 and older.)
Please do not contact us reporting issues or things not working for the legacy themes listed.
It's been a hard break up and we are simply done with them now. Thats it. Unless you wish to sponsor or take over further development.