Concentrations of risks - Vendor Concentration Risk (Details) - Supplier Concentration Risk - Tangshan Huida Ceramic Group Co., Ltd	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023
Cost of Goods and Service Benchmark
Concentration Risk [Line Items]
Concentration risk (as a percent)	55.50%	54.70%
Accounts Payable
Concentration Risk [Line Items]
Concentration risk (as a percent)	69.60%	71.40%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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