Contract assets - Schedule of Contract Assets (Details) ¥ in Thousands, $ in Thousands	Dec. 31, 2024 CNY (¥)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 CNY (¥)
Contract assets [Abstract]
Arising from performance under construction contracts	¥ 2,194		¥ 88,637
Loss allowance	(2,194)		(10,953)
Total	¥ 0	$ 0	¥ 77,684

The amount of an entity’s right to consideration in exchange for goods or services that the entity has transferred to a customer, when that right is conditioned on something other than the passage of time (for example, the entity’s future performance).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 15
-IssueDate 2025-01-01
-Paragraph 105
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2025-en-r&anchor=para_105&doctype=Standard
-URIDate 2025-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 15
-IssueDate 2025-01-01
-Paragraph 116
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2025-en-r&anchor=para_116_a&doctype=Standard
-URIDate 2025-03-27

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2027-01-01
-Name IFRS
-Number 19
-IssueDate 2025-01-01
-Paragraph 105
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_105_a&doctype=Standard
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2027-01-01
-Name IFRS
-Number 19
-IssueDate 2025-01-01
-Paragraph 105
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_105_a&doctype=Standard
-URIDate 2025-03-27

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant