Bank loans - Outstanding balance of bank loans (Details) |
Jun. 30, 2026
CNY (¥)
|
Jun. 30, 2026
USD ($)
|
Dec. 31, 2025
CNY (¥)
|
|---|---|---|---|
| Short-term bank loans | |||
| Short-term bank loans | ¥ 12,240,000 | $ 1,803,953 | ¥ 15,240,000 |
| Bank of China | |||
| Short-term bank loans | |||
| Short-term bank loans | ¥ 5,000,000 | $ 736,909 | |
| Effective interest rates | 3.35% | 3.35% | |
| Industrial and Commercial Bank of China | |||
| Short-term bank loans | |||
| Short-term bank loans | ¥ 3,740,000 | $ 551,208 | |
| Effective interest rates | 3.00% | 3.00% | |
| Agriculture Bank Of China | |||
| Short-term bank loans | |||
| Short-term bank loans | ¥ 3,500,000 | $ 515,836 | |
| Effective interest rates | 3.25% | 3.25% | |
| China Construction Bank | |||
| Short-term bank loans | |||
| Effective interest rates | 3.05% | 3.05% |