Summary of significant accounting policies - Liquidity (Details) - USD ($) |
3 Months Ended | 6 Months Ended | |||||
|---|---|---|---|---|---|---|---|
Jun. 30, 2026 |
Mar. 31, 2026 |
Jun. 30, 2025 |
Mar. 31, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
Dec. 31, 2025 |
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| Accounting Policies [Abstract] | |||||||
| Net loss | $ (1,126,662) | $ 1,143,165 | $ 1,364,465 | $ 815,557 | $ 16,503 | $ 2,180,022 | |
| Net cash provided by (used in) operating activities | 1,815,957 | $ 195,667 | |||||
| Cash and cash equivalents | 4,400,000 | 4,400,000 | |||||
| Short-term loans | $ 13,034,989 | $ 13,034,989 | $ 11,868,828 | ||||
| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Amount of cash and cash equivalent. Cash includes, but is not limited to, currency on hand, demand deposit with financial institution, and account with general characteristic of demand deposit. Cash equivalent includes, but is not limited to, short-term, highly liquid investment that is both readily convertible to known amount of cash and so near maturity that it presents insignificant risk of change in value because of change in interest rate. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Amount of cash inflow (outflow) from operating activity, including, but not limited to, discontinued operation. Operating activity includes, but is not limited to, transaction, adjustment, and change in value not defined as investing or financing activity. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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