[KevinH]

Getting the sample epub that shows the issue is key here. I have continually tried using normal find and replace in All CSS Files and with all of my test epubs and I am not seeing any crashes. I have tested with macOS and Linux extensively.

So if you need help with the Borkify plugin, please let us know.

Also, have you tried taking a copy of the epub and deleting all but the first cover xhtml file and the css and saving it under a new name. Then try recreating the crash with that shrunken epub. If so, you could probably safely post that greatly shrunk version in this thread under fair use rules as it would only be valuable for debugging and not hurt the book's sales.