This is posted simply to be helpful to anyone like me at my low level of CSS understanding (I can change color codes and add new/different fonts in basic css), not to complain or ask for more help.
The concept of "specificity" and overriding hard-coded Flarum css by adding to the Custom CSS box in Flarum Admin requires understanding first the basics and priorities of css elements (ID - CLASS - TYPE).
Without a mastery of these basic structural concepts, you are unlikely to be able to address the complex issues of "specificity" which are detailed here:
My advice is if simply adding to Custom CSS doesn't work for your situation, just edit forum.css manually, and whenever the workings of Flarum overwrite forum.css and eliminate your modifications, just re-upload your modified forum.css (it helps to save a backup somewhere) periodically as needed. (I guess I could figure out a cron job to just reload it automatically every hour or day). Of course, if you use Cloudflare, dont forget to turn on Developer Mode so the old cached reverted forum.css version doesn't keep appearing. Also don't forget to clear your browser cache entirely and restart the browser for the same reason.
Life's too short for me to learn most of CSS to prevent some letter tops from being cut off. But based on my experiments, the above instructions from Clark are accurate, and I was able to get part of the modifications added to Custom CSS to work, but not completely. I needed more understanding of "specificity" and I cannot afford to master CSS basics first in order to tackle it. If I understood the hierarchy of CSS elements and the relative weighting of duplicative elements, I probably wouldn't have had any questions in the first place.
This is a vivid example for me of how the last 5% of something eats up 95% of the time and why seemingly simple individual customizations can add enormous complexity to a "simple" piece of software.
Thanks again to all who helped. Go Flarum.
