Why not using HTML instead of PDF? I'm the author of an extension that allows to save faithfully a web page into an HTML file [1]. From my point of view, that should be the best solution for archiving web pages in a file. Votes on HN disagree with me though [2], I wished I could understand why.

[1] https://github.com/gildas-lormeau/SingleFile

[2] https://news.ycombinator.com/item?id=18243721