v3.26.1
Summary of significant accounting policies (Details 4)
12 Months Ended
Dec. 31, 2025
USD ($)
Dec. 31, 2025
CNY (¥)
Dec. 31, 2024
CNY (¥)
Dec. 31, 2023
CNY (¥)
Total revenues $ 60,045,146 ¥ 422,045,319 ¥ 541,487,420 ¥ 580,016,414
Mainland PRC [Member]        
Total revenues 40,504,749 284,699,784 414,763,523 540,294,309
HONG KONG        
Total revenues 19,540,397 137,345,535 126,723,897 29,612,277
International [Member]        
Total revenues ¥ 10,109,828