Measures
All the participants in the intervention or control group were assessed at three timepoints: baseline (T0; prior to intervention), post-intervention (T1; 11 weeks after the baseline), and follow-up (T2; 19 weeks after the baseline). The measures included demographic variables and study outcomes. Demographic variables were collected at baseline. We collected gender, year of birth, class, grade, name of the school, residence (rural or urban), and guardians for demographic information. Study outcomes were introduced in below sections. Data were collected via online questionnaires in the app and in the classrooms.