What kind of development process did Ci in Song Dynasty go through? Who are the representative writers in each stage? (At least three) What are the main features?

Song ci is more original than song ci. "Poetic and picturesque" is a common view of Song people, which makes Song ci more exquisite and emotional than Song ci in art, because it is less solemn and less formal, and its free expression shows the true temperament and true face of the poet. Song Ci has experienced a development process in the expansion and evolution of theme, style and technique. Song ci from Liu Yong to Su Shi. Su Shi is a great poet and an innovator of Ci. He turned Ci into a new poetic style that can express rich life content and complex thoughts and feelings, and is no longer attached to music. Created a variety of artistic styles, and the creation of Su Ci directly opened up Xin Qiji's unrestrained school. Yan Shu, Qin Guan, Zhou Bangyan, Li Qingzhao, Lu You and Jiang Kui. He was an important poet in the Song Dynasty. Many have their own creations and achievements.