Smartphone Usage Student Behavior Cellphone Use Smartphone Restrictions Smartphone Use Student Well-being Smartphone Use in Schools Mobile Device Management Device Usage Policies Screen Time Management Mobile Phone Use Social Media Use Artificial Intelligence Mobile Device Restrictions Handyverbot an Grundschulen Mobile Phones Mobile Phone Regulations Social Media in Schools Phone Usage Rules Digital Device Management Cellphone Bans Smartphone Bans Biometric Identification Student Wellbeing Cellphone Usage Cell Phone Bans Cell Phone Use