google sign-in3 authentication1 css1 css buttons1 dark mode1 facebook sign in1 firebase1 firestore1 flutter1 flutter firebase1 friend requests1 google button1 group chats1 html form buttons1 html5 buttons1 language support1 light mode1 login buttons1 modern design1 multimedia messaging1 otp verification1 profile editing1 push notifications1 real-time messaging1 rtl support1 sharing options1 sign-in with google button1 social login buttons1 social sign in1 social sign-in1