Short Story - Underground Dystopian possibly Steampunk

I remember reading a story about possibly a boy and girl living in an underground city because of some event that sent the population underground - it was a short story, I believe, possibly in SF/F, or Asimov's, or Weird Tales, and it had the same overtones as "This Time of Darkness" by Helen Hoover and "Dark Universe" by Daniel Galouye, but I'm certain it was a short story, not a novel. I don't believe it was associated with a war or nuclear accident, but I could have forgotten that part. I remember it really had a steampunk flavor. Any help would be appreciated:)