Determinants of health literacy in early childhood care among marginalized ethnic communities: a cross-sectional study in three border provinces of Thailand - Nathamon Wutthipan; Kunnara Maneekunwong; Pimkanabhorn Trakooltorwong; Srisuluk Kietmaneerat; Chuntana Reangsing; Khanittha Pitchalard; Salisa Kodyee; Katemanee Moonpanane (International Journal for Equity in Health, 2026)