Short term investments (Details) |
Dec. 31, 2025
USD ($)
|
Dec. 31, 2025
CNY (¥)
|
Dec. 31, 2024
CNY (¥)
|
|---|---|---|---|
| Platform Operator, Crypto Asset [Line Items] | |||
| Marketable securities | $ 161,918,194 | ¥ 1,138,090,600 | ¥ 149,583,000 |
| Fair Value, Inputs, Level 1 [Member] | |||
| Platform Operator, Crypto Asset [Line Items] | |||
| Marketable securities | 1,138,090,600 | 149,583,000 | |
| Fair Value, Inputs, Level 2 [Member] | |||
| Platform Operator, Crypto Asset [Line Items] | |||
| Marketable securities | |||
| Fair Value, Inputs, Level 3 [Member] | |||
| Platform Operator, Crypto Asset [Line Items] | |||
| Marketable securities |