We created our own system of elements, but we did lean slightly on iOS Style-guide for iOS app and to Material Design for Android app (date picker, fingerprint or pin conformations, etc.)Design changed and developed trough time. We learned a lot from user testing, which we did for about 1 year before commercial launch, on over 150 alpha and beta testers. We created an iOS and Android app that connects do Klevio device. At fist the app's only feature was unlocking doors remotely. But already during our beta testing, we expanded the features to sharing and revoking keys, and an event log - so users could see who was entering their homes or offices. Now, users can:- unlock doors remotely- share and revoke keys, instantly- view an event log- issue time-limited keys- soon, users will be able to speak trough the app with the person standing outside.