index.html.in: refactor resize_ticket() to use CSS transforms

index.html.in: refactor resize_ticket() to use CSS transforms

While it would have been nice being able to revert to the initial
ticket size by erasing the CSS "transform", doing so makes the
transitions wonky: with Commuter Bus and MARC Train tickets, it first
transitions down to the BaltimoreLink ticket size, and then back up to
the initial attribute-based size.