There are two methods to login to the Ghost Admin area of a publication hosted on Ghost(Pro):
Login from Ghost.org
Go to https://account.ghost.org/signin/, or click Sign in from https://ghost.org, and enter your site address.
Login from your site
You can also log in directly from your publication, by appending /ghost to the end of your site URL.
For example, you can login by going to yourdomain.com/ghost, OR, you can also use your ghost.io site address, subdomain.ghost.io/ghost. Either method will take you directly to your site's login page so that login credentials can be entered for access.
Having trouble logging in?
If you're having trouble signing into your site as a staff user, and no longer remember your password, you can perform a password reset directly from the Ghost Admin login area.
To reset your password, enter in the staff user email address, then click Forgot? This will trigger a password reset email to your inbox. Once the password is reset, you can login once more using your new credentials.
If you're still unable to login, or can't recall the email address that was used with your Ghost(Pro) site, contact support@ghost.org for help!