The card version looks nice and usable, but the test flip has some issues. Works nice in IE10, but in Crome, the font gets ugly and has drawing artifacts (see http://imgur.com/aXwvVr8 ), but that's chrome and not your fault :)

Also, in IE10, the input of the card is a bit off, where you can't read it properly ( http://imgur.com/NF7lXbQ ) and the update button doesn't work...