STUPIDLY I left dd(2) alone in the sitting room with the MacBook.
When I came back, she had managed to turn all the windows black. When I open an email, the window is black, with writing reversed out in white and yellow.
When I open a word document, the same.
It's like going back to DOS. Worse. It's giving me a migraine just looking at it.
I've gone into Preferences and investigated the 'Appearance' button, but it only gives me two options - black or graphite - and clicking on either doesn't seem to work.
Can anyone help?