What are the characteristics of Yan Zhenqing's calligraphy?

Yan Zhenqing is the most influential calligrapher in the history of calligraphy after Wang Xizhi. Su Dongpo once spoke highly of it. What he said was: "It is exhausting for the world to read the book to Yan Lugong." Yan Zhenqing's words are written in seal script and official script, which are solemn, simple, bold and magnificent. The style he created is called "colourful style".