I’ve looked at other suggestions for similar problems, e.g. https://www.positioniseverything.net/explorer/floatIndent.html and various alignment and padding ideas in this support forum, but none have made any difference to my own problem.
What makes the problem different is the gradual move of the content to the left as you go down the page. That seems hard to explain in my CSS.
Reloading the page often fixes the basic readability of the content, but will introduce seemingly random indents, as I mentioned before.
Anyone up for the challenge?