Okay, it looks like we've solved the tech problem here…and by "we," I mean a number of folks who wrote in with suggestions and reports. The most helpful was a gent named Mike Everleth who figured out where in the CSS file I needed to add something. (For those of you WordPressing out there: It was the background-color code for white, added to the label "art-content.")
A few folks with steam-powered browsers are still reporting minor things wrong but if no one reports anything major in the next 24 hours, I'm switching back to the blue background…and hopefully, this text area will remain white for all. I have some other features to install here shortly and I hope they won't cause any woes.