Opera under Linux is, well, strange! Everything is wrong compared to how it appears under a Windows environment. I wish I could just have the Sans font for everything, because at the moment a lot of text is too small, and yet on some pages the text is huge. It's really getting on my nerves! I downloaded Firefox just to see how that displayed, and that was fine, too. It seems to be a problem confined only to Opera.
There's nothing in /opt/
Thanks for the suggestions thus far.