v3.26.1
Income taxes - Income taxes paid, disaggregated by jurisdiction (Details)
12 Months Ended
Dec. 31, 2025
CNY (¥)
Dec. 31, 2025
USD ($)
Dec. 31, 2024
CNY (¥)
Dec. 31, 2023
CNY (¥)
Income taxes        
Income taxes paid ¥ 5,791,999 $ 828,245 ¥ 144,224,535 ¥ 43,369,793
Hong Kong        
Income taxes        
Income taxes paid 5,631,579 805,305    
Others* (PRC, US)        
Income taxes        
Income taxes paid ¥ 160,420 $ 22,940