Thanks. That worked. I’m guessing it was the apostrophe that was causing the errors before. I’ll have to do up a child theme later, but for now, I put it at the end of the functions file. I haven’t made any other adjustments to the theme itself, so it won’t be hard to fix (and I have to do it again if there’s an update (at least until I get it in a child theme).
As an aside, I know this is a fixed-width theme, but is there any easy way of modifying that to make it slightly wider?