There is nothing to sign into yet
A login form here would be theatre. Identity is not open, so the honest thing is to say so, show you exactly what is being built in its place, and let you decide whether to wait.
When it opens, it opens with the terms published first — never the other way round.
Three things have to be true at the same time before a door is worth walking through. None of them is a login screen.
Portable identity
An identity you can carry out of Rebirth intact, including everything attached to it.
The personal record
Capability, evidence and contribution, held against the person rather than the account.
Recovery without a hostage
Getting back in cannot depend on one company continuing to exist. That is not solved yet, and we will not pretend otherwise.