v3.26.3
SHARE-BASED COMPENSATION - Share options (Details)
$ / shares in Units, ¥ in Millions, $ in Millions
6 Months Ended 12 Months Ended
Jun. 30, 2026
USD ($)
$ / shares
shares
Jun. 30, 2026
CNY (¥)
tranche
shares
Jun. 30, 2025
CNY (¥)
Dec. 31, 2025
tranche
$ / shares
shares
Dec. 31, 2023
tranche
shares
Jun. 30, 2026
CNY (¥)
shares
Number of Options            
Share options outstanding at the beginning of the period (in shares) | shares   24,406,030        
Granted (in shares) | shares   128,720        
Exercised (in shares) | shares   (98,140)        
Share options outstanding at the end of the period (in shares) | shares   24,436,610   24,406,030    
Share options vested or expected to vest (in shares) | shares 22,460,850         22,460,850
Share options exercisable (in shares) | shares 4,498,510         4,498,510
Weighted Average Exercise Price            
Share options outstanding at the beginning of the period (in dollars per shares) | $ / shares $ 2.8          
Granted (in dollars per shares) | $ / shares 2.8          
Exercised (in dollars per shares) | $ / shares 2.8          
Share options outstanding at the end of the period (in dollars per shares) | $ / shares 2.8     $ 2.8    
Share options vested or expected to vest (in dollars per shares) | $ / shares 2.8          
Share options exercisable (in dollars per shares) | $ / shares $ 2.8          
Weighted Average Remaining Contractual Life and Aggregate Intrinsic Value            
Share options outstanding, Weighted Average Remaining Contractual Life (in years)   6 years 10 months 24 days        
Share options vested or expected to vest, Weighted Average Remaining Contractual Life (in years)   6 years 10 months 24 days        
Share options exercisable, Weighted Average Remaining Contractual Life (in years)   6 years 11 months 1 day        
Aggregate Intrinsic Value            
Share options outstanding, Aggregate intrinsic value | $ $ 34          
Share options vested or expected to vest, Aggregate intrinsic value | $ 31          
Share options exercisable, Aggregate intrinsic value | $ $ 6          
Recognized share-based compensation expenses | ¥   ¥ 265.0 ¥ 247.0      
Aggregate intrinsic value of options exercised | ¥   ¥ 1.0        
Share options            
Aggregate Intrinsic Value            
Weighted-average grant date fair value | $ / shares $ 1.33     $ 1.34    
Total unrecognized compensation expense | ¥           ¥ 131.0
Weighted-average recognition period of compensation expense (in years)   2 years 9 months 7 days        
Share options            
Aggregate Intrinsic Value            
Recognized share-based compensation expenses | ¥   ¥ 84.0        
Senior officers | Share options            
Number of Options            
Granted (in shares) | shares   128,720   888,210 28,625,350  
Aggregate Intrinsic Value            
Number of tranches | tranche   2   3 5  
Period for remaining percentage vested   2 years   2 years 2 years  
Second anniversary of the stated vesting commencement date | Senior officers | Share options            
Aggregate Intrinsic Value            
Share-based payment award, vesting percentage   50.00%   50.00% 50.00%  
Vesting ratably over the following two years | Senior officers | Share options            
Aggregate Intrinsic Value            
Share-based payment award, vesting percentage   50.00%   50.00% 50.00%