iPad does not see external stylesheet

Question

Days of Internet research and worsening frustration lead me here. I cannot figure this out. Perhaps a wiser person can help.

Using web developer tools, every site page displays fine in every tested browser. However, when I check on an actual iPad and iPhone, no page displays correctly. What's wrong is that none of the CSS in style.css is executing on the iPad / iPhone.

I am using bootstrap, which it sees, but it does not see my style sheet (css/style.css). I have tested too many things to list, including absolute versus relative URLs, and rearranging the link tags in the header.

I tested inline and head-embedded styles and both work. But this is unacceptable to me.

I removed all code from the footer, leaving one div with a class from the external stylesheet, and that did not work. The iPad is blind to it.

I cannot debug the iPad from the iPad (I know Safari has instructions for this), but I have other bootstrap sites I coded that work fine and comparing them I cannot see what I am doing differently now.

I re-booted my iPad many times in case it was a cache issue.

I left out code in this question because I do not know what code to show. I can provide code or URLs or anything else if that helps. The pages are published.

I appreciate any assistance. Thank you.