There are a few lightly crude moments, which are mostly clustered in the first season and cleared up in the second and third (with a few exceptions - see parent's guides for each individual episode).

Nothing or mild.

'God' and 'Bloody' are used sometimes

Usually nothing stronger than blo-dy or G-. G-d-it is used a few times. Twice there is the use of "anal" as an expression (once in season 1 and once in season three). There are one or two slightly stronger words in season 1 (see parent's guides for each individual episode).