Citing github page limits:
"Published GitHub Pages sites may be no larger than 1 GB"
Does this means 1GB overall my pages or 1GB for each github page?
The limit means the site as a whole; that is, all of the pages taken together.
Since a GitHub Pages site is designed to be used as a website for your open source project or as a personal site, and as a practical matter 1 GB for a single web page is too large to render in a modern web browser efficiently, it wouldn't be logical for GitHub to state that a single web page may be at most 1 GB.