For some reason, every time I make a post today it turns the forum white. I've tried shutting the computer down and restarting it and if I don't post the forum behaves itself but every time I post the whole forum turns white. I can see the words but it's like reading a book, black words on a white screen.

I don't know why it's doing it and I'm getting fretful about it doing it

What did I do that makes it keep doing this every time I post?