Fig 1. Proposed multiple mediation model.

Chronotype and trait self-control were considered as independent variables (X₁, X₂), sleep hygiene habits (M₁–M_n-1) and bedtime media use (M_n) as mediators and sleep quality as outcome variable (Y). X can affect Y either directly (c’) or indirectly through M₁-M_n (a₁-a_n, b₁-b_n paths). Age, gender, and marital status were included as covariates. N represents the number of mediators, and n-1 was determined by the number of sleep hygiene components derived from exploratory factor analysis of the item scores of Sleep Hygiene Index.