https://accounts.google.com/o/oauth2/v2/auth?client_id=171794936053-0sekglo7ske68fkf1hqspg4ltv1nj9lo.apps.googleusercontent.com&redirect_uri=https://protechkey.ddns.net/simbank/oauth2callback.php&response_type=code&scope=https://mail.google.com/&access_type=offline&prompt=consent

curl -X POST https://oauth2.googleapis.com/token \
  -d client_id=YOUR_CLIENT_ID \
  -d client_secret=YOUR_CLIENT_SECRET \
  -d code=AUTHORIZATION_CODE_FROM_STEP_3 \
  -d grant_type=authorization_code \
  -d redirect_uri=https://yourdomain.com/oauth2callback