UPDATE: I discovered that if the browser (Chrome or Edge) recognizes me as the author of the post, then the headers are blue colored links. If I use incognito / in private browsing, the header text is black as I requested. The external links within the post are blue and easy to recognize. That is what I needed most.
You can put this topic to rest as far as I am concerned. I am now happy with the current status.
THANK YOU for a design that gets me many compliments on your work!