In Chapter 3, page 79 you include code (link tags) in the index page to link to the separate files for the header and footer CSS files. For the footer, you use a simple relative link to the footer file, but for the header you appear to use an absolute reference to an external file (i.e. "https://maccdn.....bootstrap.min.css").
I have created the local header file as instructed. When I alter it locally, the changes are reflected in the active page, so I know that the header content is indeed being driven by the local file.
So my question is: Why is the link tag to the header file not coded simply as a relative link (like the footer is)? And why, if the code refers to an external file as written, is the header formatting driven off the content of that external file (instead of my local one)?
Thanks