Are Declarative and Imperative patterns kind of design patterns?

I read this sentence "C# supports patterns for purity" in the book C# 8.0 in a Nutshell from O'Reilly. It continued that "Core to functional programming is avoiding the use of variables whose values change, in favor of declarative patterns." I tried to understand what is declarative patterns. But I couldn't find the declarative pattern as any subcategories of design patterns. Can anyone explain to me if the declarative pattern is different from design patterns such as Behavioral, Creational, and Structural?