Briefly describe the main content of Li Sao, about 300 words.

Li Sao is a passionate political lyric poem and an artistic masterpiece combining realism and romanticism. Borrowing a large number of mythological materials from Chu and using absurd fantasies, it greatly expanded the realm of poetry and presented magnificent features. This opened up a new path for the creation of China's classical poetry. Poets with strong personality and emotion in later generations, such as Li Bai and Li He, were greatly inspired.

The perfect combination of Li Sao's high artistic achievement and its rich and profound ideological content makes it a masterpiece in the history of China literature and has a far-reaching influence on later generations. Mr. Lu Xun once praised it as "an excellent speech" (an outline of China's literary history) and gave a high evaluation.

Song Qi, a famous historian and poet in Song Dynasty, said: "Li Sao was the ancestor of Ci Fu and was written by later generations. You can't be polite, you can't exceed the moment. " In other words, Li Sao not only opened up a vast literary field, but also was an unattainable model of China's poetry and prose.