Can someone explain me how slashing works from a technical point of view?

I know the ETH 2.0 POS algorithm uses slashing to avoid bad behaviour, but in order for it to work, there must be hard rules for when someone will be slashed, right?

I don't really understand it yet and got a lot of questions. What event is considered slashable? Who decides if someone will be slashed? Will things like censoring be slashable? If yes, how do you detect censoring? If no, what can we do to avoid censoring?

Can anyone help me understanding how exactly slashing works from a technical point of view? A Link would do too, but all links i found only say you'll be slashed for bad behaviour, but do not explain how it exactly works