shifting a website out of google sites and into github pages

Google sites recently announced a shift to "New Sites" with a mandatory upgrade for "Old Sites". Since New Sites had some disadvantages like inability to choose our own font size for particular lines of text (as we would like to do for important announcements, making them large), I looked around for options - whether to move to Blogger or New Sites or do something else. New Sites also had the disadvantage of breaking our photo gallery page when using the migration tool. Blogger would break existing page urls. So, since there was only static content, thought about hosting it on github pages. 

The move was relatively straightforward, though I took a long time since I did a drag-and-drop commit after each change instead of using the commandline. The changes I needed to make were:

1. removed all scripts
2. jpg and css links made relative, uploaded to suitable directories
3. created a template with the above, to which the changes needed for each page were:
   
   1. the title and other header info (at 4 places near each other)
      
   2. the div with id sites-chrome-sidebar-left
   3. the div with id  sites-canvas-main-content
   4. the h3 tags with page heading 

After setting the CNAME records on the domains DNS servers, even 4 days later, the "Enforce HTTPS" was not available, with the message "Not yet available for your site because the certificate has not finished being issued." One of the suggested workarounds was to remove and re-add the custom domain. I did that, and immediately Enforce HTTPS was enabled.