v3.26.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revenue recognition (Details)
¥ in Thousands, $ in Thousands
12 Months Ended
Dec. 31, 2025
CNY (¥)
Dec. 31, 2025
USD ($)
Dec. 31, 2024
CNY (¥)
Dec. 31, 2023
CNY (¥)
Goodwill [Line Items]        
Variable consideration ¥ 196,912   ¥ 47,935 ¥ 0
Extended warranty service expense 4,285   8,909 10,413
Accrued warranty liability        
Balance as of the beginning of the year 43,607   28,425 17,694
Warranty provision 48,731   32,078 26,247
Consumption (14,666)   (16,896) (15,516)
Balance as of the end of the year ¥ 77,672 $ 11,107 ¥ 43,607 ¥ 28,425
Minimum        
Goodwill [Line Items]        
Period for extended warranty 1 year 1 year    
Maximum        
Goodwill [Line Items]        
Period for extended warranty 2 years 2 years