What calligraphy technique is used for the Mangosteen plaque in Quanzhou?

Quanzhou's "Mountain Bamboo" plaque is a desktop plaque, with a width of 3.75 meters and a height of 3.7 meters. Granite columns on both sides are embedded in diabase squares, and the ink of "Mountain Bamboo" and "Huiwengshu" is engraved on the front. The font is flowing, vigorous, calm and elegant, which is very distinctive.