Right-of-use assets and lease liabilities - Operating lease expenses (Details)	6 Months Ended
Jun. 30, 2026 CNY (¥)	Jun. 30, 2026 USD ($)	Jun. 30, 2025 CNY (¥)
Right-of-use assets and lease liabilities
Amortization of right of use assets and interest of lease liabilities	¥ 298,274	$ 43,960	¥ 548,350
Operating lease expenses with an initial term of 12 months or less	51,574	7,601
Total operating lease expenses	¥ 349,848	$ 51,561	¥ 548,350

Amount of amortization expense attributable to right-of-use asset and interest paid on liabilities arose on operating leases.

No definition available.

+ Details

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Period Type:	duration

- References

No definition available.

+ Details

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- Definition

Amount of single lease cost, calculated by allocation of remaining cost of lease over remaining lease term. Includes, but is not limited to, single lease cost, after impairment of right-of-use asset, calculated by amortization of remaining right-of-use asset and accretion of lease liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 53
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479589/842-20-55-53

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-4

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- Definition

Amount of short-term lease cost, excluding expense for lease with term of one month or less.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 53
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479589/842-20-55-53

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-4

+ Details

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