v3.26.1
Income taxes - Current and deferred component of income tax expense (Details)
12 Months Ended
Dec. 31, 2025
CNY (¥)
Dec. 31, 2025
USD ($)
Dec. 31, 2024
CNY (¥)
Dec. 31, 2023
CNY (¥)
Income taxes        
Current tax expense ¥ 549,695,672 $ 78,605,435 ¥ 432,950,473 ¥ 278,695,689
Deferred tax expense (benefit) (258,046,348) (36,900,137) (27,248,759) (17,565,186)
Total income tax expense ¥ 291,649,324 $ 41,705,298 ¥ 405,701,714 ¥ 261,130,503