This isn't a hosted login system — GitHub Pages can't run a server. Instead, publishing works by committing directly to this repo using a GitHub Personal Access Token. Create a fine-grained token (Settings → Developer settings → Personal access tokens → Fine-grained tokens) scoped to only this one repository with Contents: Read and write permission, and give it a short expiry. Never share it, and don't paste it into any other site. It's kept only in this browser tab's memory — it's not saved anywhere.