You can implement this login system in your website. There is a password reset and a regestration page. Although not super secure, it is a good tool to use on GitHub Pages since it does not support PHP. Use a free password hasher tool to hash your whole JavaScript file.
You can change the password and usernames. Just open the script
folder and then open each JavaScript file and edit the passwords and usernames.
If you are having troubles contact me at info@michaelbateman.ca.