What's the Name of That Book??? discussion

Does anyone remember a book about "return of magic" type disaster and a kid with a katana and a unicorn traveling companion? I believe the book came out in the 1990s, but I could easily be off by a decade or more. I'm not positive, but may have been YA.

The nature of the disaster was all electrical devices stopped working. Guns worked, but ammunition was hard to get.

Toward the end of the book he hits a town and realizes civilization has already started to reassert itself. People are having elections, reopening schools, etc. But due to the disaster he personally never went to high school so he's not sure he will have a place in society any more.

Ariel?

I don't recognize that cover but I'm pretty sure that's it. Thanks!

Cheers!

(Scroll down a bit on that page and it'll show you other editions - I just picked the first that came up.)