both

Approval and Referendum Phase - in parallel:
Approval - 24 hours: During this single day window, the proposal must receive approval from the designated Approvers.
Referendum - 5 days: Locked CELO holders vote YES or NO on the proposal during this period.

and the https://github.com/celo-org/docs/blob/main/home/protocol/governance/overview.mdx#approval

are wrong

Approval used to be a stage. but now approval can happen any time durring referendum or execution stages. see https://github.com/celo-org/celo-monorepo/blob/master/packages/protocol/contracts/governance/Governance.sol#L471

Once a proposal is upvoted on and proceeds from the queuue aka is dequeued it is then in referendum stage for 7 days (can be approved at this time).

If it passes quorum it then goes to execution stage (can also be approved at this time).

But can only be executed once it is fully approved.