What was the level of official script in Tang and Song Dynasties?

Although the official script of Tang Dynasty can't be compared with Han Li, although it didn't become the strongest sound of Tang Dynasty calligraphy like regular script, running script and cursive script, it occupies an important position in the history of calligraphy. In the Tang Dynasty, the stylization of official script was prominent, with regular script being the most, and the words used in writing lacked change. The same strokes were similar, almost overlapping, with more rules and less changes. , Han Zemu, Liang Shengqing, Shi, Cai, Yin Zhongrong, Bai Yiqian, Gui Deng, etc. The four great calligraphers are Han Zemu, Cai, Shi.