Edit to add: apologies all around, dear steampunk enthusiasts! Fwiw Steampunk really didn't enter anything close to the mainstream in my corner of the U.S. until that movie came out, and afterwards seemed to be everywhere I looked, so I don't think it was a totally unreasonable assumption. (And yes, I knew the movie was based on older material, but didn't know to what extent the visual aesthetic had already been defined.) As penance I will purchase one Steampunk item from my local costume store and wear it to my next all-hands work meeting.