Well, there were two countries in the era when the story took place, Nanli and Beili. The South favors girls over boys, while the North favors boys over girls. The heroine and the hero were born in Nanli, but their thinking transcended the established "women are superior to men" of that era.
Regarding the classification of the article as BL... There will be a BL part in the article, but it is not the main line.