My host does do backups, but it takes days to have them refer back. I’ll ask them about the staging environment!
I think I’ve only done custom css, that doesn’t count as core theme code, right?
I’m thinking that it might be better to wait so that I can launch at the time I have told everyone I will, and then deal with any problems later on… Is that ok to do, or will it cause trouble (forced updates or incompatibility issues)?