Your Firefox start page ( http://www.google.com.au/firefox?client=firefox-a&rls=org.mozilla:en-US:official ) may or may not have a CSS error.
And my poor little heart skips a beat.
Until I realise that its not me. Its you. I think.
Maybe its a Firefox Bug?
I’m sure you can get to the bottom of it, you are so big, strong and clever.