Underlying framework

Hello,

Contracts are the underlying framework for every aspect of business activity. You have contracts with everyone—the HVAC people for your house; the warranty for your car; the service contract for the photocopy machine in your office; the collective bargaining agreement that either governs your relationship with your employees or governs the relationships between those employees and your critical suppliers.

https://www.law.com/newyorklawjournal/2020/03/23/covid-19-and-contracts-under-pressure/?slreturn=20200303021906

How can I interpret "underlying framework"? Does it mean building block?