Assessment of eligibility and randomization

After registering with a self-chosen email address on the study website, applicants received detailed information about the study procedure. They were further informed about the possibility to withdraw from the intervention and/or study at any time without any negative consequences. Applicants were asked to complete an online screening questionnaire and to sign the informed consent form. As soon as participants had completed the baseline assessment and met the inclusion criteria, they were randomized in 1:1 ratio to the IG or WCG. A research assistant not otherwise involved in the study performed block randomization with varying block sizes using an automated computer-based random integer generator (RandList, DatInf GmbH, Tübingen). Once randomization had been completed, participants in the IG received immediate access to the intervention while participants in the WCG received access 12 months later.