v3.26.3
Summary of significant accounting policies - disaggregates revenue (Details)
 6 Months Ended
Jun. 30, 2026
CNY (¥)
Jun. 30, 2026
USD ($)
Jun. 30, 2025
CNY (¥)
Summary of significant accounting policies      
Total revenue ¥ 8,274,218 $ 1,219,469 ¥ 9,383,590
Revenue recognized over time      
Summary of significant accounting policies      
Total revenue 8,208,137 1,209,729 9,175,518
Revenue recognized at a point in time      
Summary of significant accounting policies      
Total revenue 66,081 9,740 208,072
Adult education supporting services      
Summary of significant accounting policies      
Total revenue 5,074,720 747,921 5,671,628
Safety technology training services      
Summary of significant accounting policies      
Total revenue 2,290,080 337,516 3,503,890
Online course services      
Summary of significant accounting policies      
Total revenue 66,081 9,740 ¥ 208,072
Customized equipment      
Summary of significant accounting policies      
Total revenue ¥ 843,337 $ 124,292