Obesity Prevention in School-aged Children

This cluster-randomized trial will develop and test an intervention technology for school-aged children. The program combines digital health technology and personalized behavior intervention through a WeChat platform. Our main question is: Does this integrated approach improve obesity related outcomes and behaviors in children? Investigator will: * Compare children receiving the program with those receiving usual care. * Track physical measures and health behaviors to measure effectiveness of intervention. * Evaluate the program's safety, implementation process, and cost-effectiveness. Findings will determine if this approach should be expanded to more communities.