Inclusion Criteria:  Participants with elevated depressive symptoms as defined by PHQ-9 score 10 or above Hong Kong residents Aged 18 or above Able to read Chinese and type in Chinese or English Have an Internet-enabled mobile device (iOS or Android operating system)  Exclusion Criteria:  Pregnancy; Using medication or psychotherapy for depression; Currently participating in other psychological intervention studies; Cognitive impairment; Having unsafe conditions and are not recommended for physical activity or a change in diet by physicians; Self-disclosure of any major psychiatric, medical, or neurocognitive disorders that make participation unsuitable or may interfere with the adherence of the lifestyle modification; Any suicidal ideation (scoring above 2 in item 9 in BDI-II) Participants with any urgent health necessity were excluded and referred.