It looks to me like they're just obfuscated words. If you look at one of the hierarchies, you see "TUdKmf-xhiy4-haAclf", then "TUdKmf-xhiy4-DKlKme-haAclf", then "TUdKmf-xhiy4". Seems like they're just taking a normal class like "note-body-wrapper" and "note-body" and obfuscating it.
What's the purpose of obfuscating css?
Make it harder to use userscripts for custom styling..?