v3.25.2
Summary of significant accounting policies (Details Narrative)
6 Months Ended 12 Months Ended
Jun. 30, 2025
USD ($)
shares
Jun. 30, 2025
CNY (¥)
shares
Jun. 30, 2024
CNY (¥)
shares
Dec. 31, 2024
CNY (¥)
Jun. 30, 2025
CNY (¥)
Accounting Policies [Abstract]          
Foreign currency transactions The balance sheet amounts, with the exception of shareholders’ equity at December 31, 2024 and June 30, 2025 were translated at USD 1.00 to RMB 7.1884 and to RMB 7.1586 respectively. The average translation rates applied to statement of income accounts for the six months ended June 30, 2024 and 2025 were USD 1.00 to RMB 6.9252, and RMB 7.1839, respectively. The shareholders’ equity accounts were stated at their historical rate. The balance sheet amounts, with the exception of shareholders’ equity at December 31, 2024 and June 30, 2025 were translated at USD 1.00 to RMB 7.1884 and to RMB 7.1586 respectively. The average translation rates applied to statement of income accounts for the six months ended June 30, 2024 and 2025 were USD 1.00 to RMB 6.9252, and RMB 7.1839, respectively. The shareholders’ equity accounts were stated at their historical rate.      
Allowance for credit losses of accounts receivable   ¥ 0   ¥ 0  
Credit losses for prepaid services fees $ 3,094 22,149   22,149  
Credit losses for other receivables 680,987     4,875,364 ¥ 4,874,917
Equity method investment 154,072       1,102,938
Impairment of long-lived assets   0   0  
Convertible notes payable (0)     ¥ 149,090,866 ¥ 0
Employee benefit $ 106,901 ¥ 765,260 ¥ 730,287    
Diluted | shares 2,776,005 2,776,005 51,465