My page throws errors in Firefox Nightly such as Expected color but found ‘undefined’. Error in parsing value for ‘background-color’. Declaration dropped. preview.htm:1:1 and Expected color but found ‘undefined’. Error in parsing value for ‘color’. Declaration dropped. preview.htm:1:1 The page references ten CSS files besides having dozens of its own CSS declarations. The issue is tha the reference provided to the error (:1:1) does not indicate where I can find the error. That is, I don't know which declaration is at fault. Is there some straighforward way to find the declaration in question?