Weird error today I thought worth posting the solution to.
If your style sheet has this line at the top Safari won’t display certain background colors.
When you create an HTML file in Dreamweaver and add CSS directly to the HTML file, it will automatically insert this into the style section. If you then copy the entire style section and create an external stylesheet, it will then remove all of your background colors. Luckily, it’s an easy fix. Just remove the charset. It’s not needed for CSS unless you’re using a foriegn language that has non-ascii characters (in the code, not the text).