I'm a Mac newbie and need advice.........I will be viewing a lot of pdf files on the Mac; I've noticed that on some documents the fonts are completely different and/or words are "bold" when they should not be. Have also noticed dashes, quotation marks, etc are missing from some of the documents. What's the deal? Is there something I'm doing wrong or do I need an "app" to correct this? If so, which one would you suggest? I downloaded and installed a PDF Reader app and it didn't help.