OK, found that section. It was set at "0"--have no idea how to interpret what that means. Tried changing to various other numbers, but saw no change in font size, even though closing and reopening browser many times.
Then just fiddled around with Ctrl and + sign, and found that the overall size of page contents increases. Neat! Really helps legibility of material and soothes tired eyes!
Is there a downloadable Manual somewhere that describes all these nice functions and features, or is there only the ONLINE manual?
It is exciting to find new functions that make K-M even more useful!