What kind of books are literature books? Do novels (including online novels) count?

Of course, novels count, but online novels are mostly, no, almost all fast food articles, for relaxation and recreation.

Literature refers to the art of using language to vividly reflect the objective reality, including drama, poetry, novels, essays and so on. It is an important manifestation of culture, which expresses inner feelings in different forms (called genres) and reproduces social life in a certain period and region.

In other words, you can experience things you can't experience elsewhere in the book, similar to Fortress Besieged, One Hundred Years of Solitude and other books.