Add simple login button?

Is there a way to show a simple “login” button or link when you don’t want to show an whole “login step”?

I want customers to understand registration is optional, whereas a formal step with a big form in front of you communicates something else… so I thought about a discrete login “link” or button would do the trick. 😉

The customer would click it and the login step would “appear”.

Would that be possible?

And keep up with the good job.