Income Taxes - Deferred income tax assets (Details) - USD ($)	Mar. 31, 2026	Dec. 31, 2025
Income Tax Disclosure [Abstract]
Capitalized start-up costs	$ 43,138	$ 16,527
Total deferred tax assets before valuation allowance	43,138	16,527
Valuation allowance	$ (43,138)	$ (16,527)

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482685/740-10-50-2

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482685/740-10-50-2

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	credit
Period Type:	instant

- References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount after allocation of valuation allowances of deferred tax asset attributable to capitalized costs.

+ References

No definition available.

+ Details

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Namespace Prefix:	yswy_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant