I swear I didn't do it on purpose!
I did mention in a comment that perhaps it was time for a change. But what happened is this...
I went to the template section of the blog and clicked on "Save Template" because I thought that would save the template I had. I would save what I had and fool around with new possibilities. But no!!! Save Template means "use" the template whose box has been checked. The spot I was looking for to save my (formerly) current template was somewhere else. I only found it later.
But anyway. So now Mental Blog has a new look. I like it fine, after a little bit of tweaking, and rebuilding the label cloud. But maybe some more tweaking. This particular template doesn't seem to offer all the colour options of the previous one, but perhaps for obvious reasons. I expect it's possible to change colours in the HTML, but I still don't know enough about code to do that.
So. Enjoy the new template. Or not. If not, let me know.