v3.26.3
Summary of significant accounting policies - Cash and cash equivalents (Details)
Jun. 30, 2026
CNY (¥)
Jun. 30, 2026
USD ($)
Dec. 31, 2025
CNY (¥)
Summary of significant accounting policies      
Cash and cash equivalents ¥ 51,837,277 $ 7,639,869 ¥ 19,773,580
PRC      
Summary of significant accounting policies      
Cash and cash equivalents ¥ 51,837,277 $ 7,639,869 ¥ 19,773,580