Follow the steps below to find this:
- Go to Setup > select Page Wrapper Editor
- Under the Security Category column, look for General with Default written below it
- This is the Page Wrapper that the login page is using
- On the Page Wrapper Editor screen, click Edit Attributes next to the Page Wrapper that you would like to be used for the log in screen
- Go to step 2. Set default for security category
- Mark the checkbox under "Set Category Default Page Wrapper"
- Click Finish