Almost everything in Greendale seems to be vintage 1960's (cars, movies, dress). I assume it is to reflect the original comic book, but I swear I saw Ambrose using a laptop computer in the first episode. Was this just to make it more topical? Or is it some kind of alternate reality?
It is left vague and ambiguous, though the show definitely includes modern elements. In an interview with Elle magazine the production designer of the show, Lisa Soper, said that they deliberately went for a "timeless" quality like its cousin Riverdale.
When you watch the show you’ll see cellphones, you’ll see laptops, you’ll see Victorian dresses. Some of these witches and creatures are hundreds of years old, so we’re trying to show that layering of history, and also trying to give everybody in the audience a chance to grab onto something that they like and that they're nostalgic for. We're not locked into a time.