I was under the impression that using two different styles for a form was not visually attracting and confusing for users.
Yet a big internet player seems to bee using a different style for their login and sign up form, which looks very unpleasant (subjective) and unprofessional.
Facebook has a Billion users at this point, so breaking their usual design in order to emphasise the form seems odd.
What kind of impact does using two forms such as Facebook in this case has? I am sure this is not an arbitrary decision.