v3.26.1
Financial risk management and fair values - Exposure to currency risk (Details) - Currency risk - CNY (¥)
¥ in Thousands
Dec. 31, 2025
Dec. 31, 2024
United States Dollars    
Disclosure of nature and extent of risks arising from financial instruments    
Net exposure arising from recognized assets and liabilities ¥ 255,405 ¥ 277,941
United States Dollars | Trade and other receivables    
Disclosure of nature and extent of risks arising from financial instruments    
Net exposure arising from recognized assets and liabilities 307,284 189,003
United States Dollars | Cash and cash equivalents member    
Disclosure of nature and extent of risks arising from financial instruments    
Net exposure arising from recognized assets and liabilities 51,247 173,001
United States Dollars | Term deposits    
Disclosure of nature and extent of risks arising from financial instruments    
Net exposure arising from recognized assets and liabilities 7,480 359
United States Dollars | Trade and other payables member    
Disclosure of nature and extent of risks arising from financial instruments    
Net exposure arising from recognized assets and liabilities (110,606) (84,422)
Euros    
Disclosure of nature and extent of risks arising from financial instruments    
Net exposure arising from recognized assets and liabilities 63,696 130,449
Euros | Trade and other receivables    
Disclosure of nature and extent of risks arising from financial instruments    
Net exposure arising from recognized assets and liabilities 22,704 43,965
Euros | Cash and cash equivalents member    
Disclosure of nature and extent of risks arising from financial instruments    
Net exposure arising from recognized assets and liabilities 61,137 93,281
Euros | Trade and other payables member    
Disclosure of nature and extent of risks arising from financial instruments    
Net exposure arising from recognized assets and liabilities (20,145) (6,797)
Great British Pound    
Disclosure of nature and extent of risks arising from financial instruments    
Net exposure arising from recognized assets and liabilities 27,027  
Great British Pound | Trade and other receivables    
Disclosure of nature and extent of risks arising from financial instruments    
Net exposure arising from recognized assets and liabilities 27,194  
Great British Pound | Cash and cash equivalents member    
Disclosure of nature and extent of risks arising from financial instruments    
Net exposure arising from recognized assets and liabilities 5  
Great British Pound | Trade and other payables member    
Disclosure of nature and extent of risks arising from financial instruments    
Net exposure arising from recognized assets and liabilities (172)  
Hong Kong Dollars    
Disclosure of nature and extent of risks arising from financial instruments    
Net exposure arising from recognized assets and liabilities 17,991 54,278
Hong Kong Dollars | Trade and other receivables    
Disclosure of nature and extent of risks arising from financial instruments    
Net exposure arising from recognized assets and liabilities 25,326 66,782
Hong Kong Dollars | Cash and cash equivalents member    
Disclosure of nature and extent of risks arising from financial instruments    
Net exposure arising from recognized assets and liabilities 4,804 2,112
Hong Kong Dollars | Trade and other payables member    
Disclosure of nature and extent of risks arising from financial instruments    
Net exposure arising from recognized assets and liabilities (12,139) (14,616)
Singapore Dollars    
Disclosure of nature and extent of risks arising from financial instruments    
Net exposure arising from recognized assets and liabilities 7,087  
Singapore Dollars | Cash and cash equivalents member    
Disclosure of nature and extent of risks arising from financial instruments    
Net exposure arising from recognized assets and liabilities 7,087  
Renminbi    
Disclosure of nature and extent of risks arising from financial instruments    
Net exposure arising from recognized assets and liabilities 4,052 3,312
Renminbi | Trade and other receivables    
Disclosure of nature and extent of risks arising from financial instruments    
Net exposure arising from recognized assets and liabilities 574  
Renminbi | Cash and cash equivalents member    
Disclosure of nature and extent of risks arising from financial instruments    
Net exposure arising from recognized assets and liabilities 4,084 8,928
Renminbi | Trade and other payables member    
Disclosure of nature and extent of risks arising from financial instruments    
Net exposure arising from recognized assets and liabilities (606) (5,616)
Other currencies    
Disclosure of nature and extent of risks arising from financial instruments    
Net exposure arising from recognized assets and liabilities 7,829 1,190
Other currencies | Trade and other receivables    
Disclosure of nature and extent of risks arising from financial instruments    
Net exposure arising from recognized assets and liabilities 2,849 18
Other currencies | Cash and cash equivalents member    
Disclosure of nature and extent of risks arising from financial instruments    
Net exposure arising from recognized assets and liabilities 5,461 1,687
Other currencies | Trade and other payables member    
Disclosure of nature and extent of risks arising from financial instruments    
Net exposure arising from recognized assets and liabilities ¥ (481) ¥ (515)