Whether a state appellate court violates the Fourteenth Amendment's Due Process Clause by sua sponte imposing an unargued, heightened evidentiary burden on a litigant

1. Whether a state appellate court violates the Fourteenth Amendment ’s Due Process Clause by sua sponte imposing an unargued, heightened evidentiary burden on a litigant —requiring “clear and convincing ” proof to overcome a community-property presumption despite an unchallenged postmarital agreement designating the property as separate — thus denying that litigant notice and any opportunity to meet the new burden and resulting in the deprivation of substantial property rights. ii STATEMENT OF