Negotiated a sign-on bonus instead of base salary when the range was capped, worked better than I thought

Offer came in at the top of the posted band and the recruiter made it clear the base wasn't moving. Almost didn't push at all since the number already looked decent. Asked about a sign-on bonus instead since that apparently comes from a different budget line, got an extra chunk added with basically no pushback. Small thing but nobody had told me base and sign-on are often negotiated completely separately.