They came back with a counter offer and I didn't realize I could also ask about the signing bonus

Negotiated the base up eight percent, felt good about it, was ready to just say yes. Mentioned it to a friend who does recruiting and she asked if I'd brought up a signing bonus to offset unvested equity I was walking away from. Hadn't even considered it was a separate lever. Asked, got half of what I floated, but half of something I didn't know existed is still a win. Apparently almost everything is separately negotiable and nobody tells you that upfront.