v3.26.1
Share-based compensation - Summary of Restricted Share Units (Details) - Restricted Share Units
¥ / shares in Units, ¥ in Thousands
12 Months Ended
Dec. 31, 2025
CNY (¥)
¥ / shares
shares
Dec. 31, 2025
CNY (¥)
¥ / shares
$ / shares
shares
Dec. 31, 2024
CNY (¥)
¥ / shares
shares
Dec. 31, 2023
¥ / shares
Share-based compensation        
Number of Share Units, Outstanding, Beginning 273,654 273,654    
Number of Share Units, Granted 273,605 273,605    
Number of Share Units, Vested 273,613 273,613    
Number of Share Units, Outstanding, Ending 273,646 273,646 273,654  
Number of Share Units, Vested and expected to vest 273,646 273,646    
Weighted-Average grant-date Fair Value per Restricted Share Unit, Outstanding, Beginning | ¥ / shares ¥ 1.84      
Weighted-Average grant-date Fair Value per Restricted Share Unit, Granted | (per share) 5.33 $ 0.76 ¥ 2.04 ¥ 1.74
Weighted-Average grant-date Fair Value per Restricted Share Unit, Outstanding, Ending | ¥ / shares 7.16   ¥ 1.84  
Weighted-Average grant-date Fair Value per Restricted Share Unit, Vested and expected to vest | ¥ / shares ¥ 7.16 $ 7.16    
Weighted Average Remaining Contractual Term (Years), Outstanding 9 years 7 months 2 days 9 years 7 months 2 days 9 years 7 months 28 days  
Weighted Average Remaining Contractual Term (Years), Vested and expected to vest 9 years 7 months 2 days 9 years 7 months 2 days    
Aggregate Intrinsic Value, Outstanding | ¥ ¥ 904 $ 904 ¥ 1,042  
Aggregate Intrinsic Value, Vested and expected to vest | ¥ ¥ 904 $ 904