It means essentially the same thing as the current 'in-vogue' phrase, "It is, what it is." It means the law is not negotiable. It may not seem just in some cases but it is, above all else, the law.
Statutes rule! Regulations are just rules for carrying out the law the legislature made by statute. If the regulation is inconsistent with the statute (and sometimes they are) they can be challenged...
Yes. Civil law is based on any code or laws passed by the legislature or law creating body for the country or political unit in question. The interpretation and any gaps in that law will be based on...