Summary of significant accounting policies - Property and equipment, net (Details) |
Jun. 30, 2026 |
|---|---|
| Motor vehicle | |
| Property and equipment, net | |
| Estimated useful lives | 4 years |
| Office equipment | |
| Property and equipment, net | |
| Estimated useful lives | 3 years |
| Leasehold improvement | |
| Property and equipment, net | |
| Property, Plant, and Equipment, Useful Life, Term, Description [Extensible Enumeration] | us-gaap:UsefulLifeShorterOfTermOfLeaseOrAssetUtilityMember |