There's a limited selection of tracks as background music that's freely selectable, but it isn't part of the mood setting in the same way it is for YAGS and ZAGS (you can check out the free demo to see what selections are available... it's the same in the full game)
If you like the music, you can download the albums by donating $10 for YAGS (or purchasing the Steam YAGS bonuses bundle) and by purchasing the ZAGS soundtrack directly on Steam
The themes are also available for listening on Spotify
Thanks for your continued support!