v3.26.1
Income taxes - Pre-tax income (Details)
12 Months Ended
Dec. 31, 2025
CNY (¥)
Dec. 31, 2025
USD ($)
Dec. 31, 2024
CNY (¥)
Dec. 31, 2023
CNY (¥)
Income taxes        
Pre-tax income ¥ 1,749,990,796 $ 250,245,356 ¥ 1,894,330,096 ¥ 1,468,577,989
Cayman Islands entity        
Income taxes        
Pre-tax income (7,544,222) (1,078,809) (7,595,959) (3,703,756)
Hong Kong entities        
Income taxes        
Pre-tax income (10,827,886) (1,548,367) 11,787,138 1,137,814
Chinese Mainland entities        
Income taxes        
Pre-tax income ¥ 1,768,362,904 $ 252,872,532 ¥ 1,890,138,917 ¥ 1,471,143,931