v3.25.1
Income tax - Reconciliation (Details)
12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Reconciliation of income tax rates      
Statutory income tax rate 25.00% 25.00% 25.00%
Non-deductible expenses (1.30%) (0.30%) (0.80%)
Additional tax deduction for qualified research and development expenses 5.00% 1.70% 0.90%
Non-taxable income 0.80% 0.40%  
Tax effect of preferential tax rate (11.10%) (0.30%) 0.80%
Effect of changes in tax rates (20.40%)    
Effect on tax rates in different tax jurisdiction 0.10% (0.60%) 0.10%
Change in valuation allowance 0.70% (27.20%) (27.80%)
Others (1.90%) 0.50% 0.10%
Income tax expense (3.10%) (0.80%) (1.70%)