Thanks to all of you who pointed out that I had forgotten to specify the size of my banner in the CSS. I added the width and height…and then had no head at all. And then I rechecked and saw that I’d forgotten to put a semi-colon at the end of each line.
Sometimes it’s as simple as that.
FYI, once I submit a comment, there’s no way back to your main page other than hitting the back button on my browser.
This should take care of that.