Toggling userChrome.css or userContent.css options overwrites/deletes them without a warning

[CheesecakeCG]

If you toggle those options and you had already had a userChrome.css or userContent.css file, you will loose it. The addon should probably only edit these files to add it's CSS rules, and make a backup before doing so. At the very least, there should be a warning that those options could result in data loss.

I'm using Pywalfox v2.0.11 and Firefox 113.0.2

[brosasaki]

Adding on that this is a pretty important issue, I just lost my userChrome to this :( please have it so a backup is made at least. It would also be nice to have the added rules tacked on to the bottom of the file instead of replacing all of them. Or even just put a copy-paste field with a single import command to add the enhancements from their own file if that's possible.