Basically sleep well and soundly. A cute goodnight message

A cultural and aesthetic mind-state that prioritizes making money, even as an “underground” or “radical” creator. The work isn’t made for money, but it’s the money that matters the most.

Meaning Sleep well.
Very well used phrase in the English - speaking world. It's been common at bedtime for many years in the form of "good night, sleep tight, don't let the bedbugs bite", or something like that.