Fair value measurements - Roll forward of Level 3 investments (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024
Roll forward of Level 3 available-for-sale debt investments
Fair value of Level 3 investments, Beginning balance	¥ 283,054	¥ 428,512
Recognised in net loss	¥ (76,458)	¥ (66,339)
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Impairment Loss Of Investments	Impairment Loss Of Investments
Recognised in other comprehensive income (loss)	¥ (43,569)	¥ (79,119)
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Asset, Gain (Loss), Statement of Other Comprehensive Income or Comprehensive Income [Extensible Enumeration]	OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment and Tax	OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment and Tax
Fair value of Level 3 investments, Ending balance	¥ 163,027	¥ 283,054

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

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- Definition

Amount of gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3).

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- Definition

Amount of gain (loss) recognized in other comprehensive income (OCI) from asset measured at fair value on recurring basis using unobservable input (level 3).

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- Definition

Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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- Definition

Indicates line item in statement of income or comprehensive income that includes gain (loss) from asset measured at fair value using unobservable input (level 3).

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Indicates line item in statement in which other comprehensive income (OCI) is reported that includes gain (loss) from asset measured at fair value using unobservable input (level 3).

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