Complete grammar as if Arka were a natural language - Arka: One of the Most Developed Conlangs

Arka has complete grammar as if it were a natural language, so its grammar is not easy.
It is easy to make an easy grammar.
It is easy to make a difficult grammar if it is an a posteriori language. The author can borrow the grammar from some languages.
It is not easy to make difficult and a priori grammar because the author must be skilled in linguistics.