What style of the times did Cao Cao and his son's masterpieces show?

The emergence of Jian 'an literature represented by Cao Cao and his son, including writers such as "Seven Scholars" and Cai Yan, set off the first climax of poetry creation. Their poems inherited the realistic tradition of folk songs in Han Yuefu, reflected the social turmoil and the sufferings of people's livelihood at that time, showed the ideal and ambition of unifying the whole country, and had a sad and generous style of the times.