Migrating CSS from Flex 3 to Flex 4

Is there a guide or document that deals specifically with migrating CSS and style attributes from Flex 3 to Flex 4? I have an application that 开发者_如何学GoI'm keeping on the 2006 namespace, but I'm having trouble with a couple concepts, like the halo only styles, the CSS namespacing conventions, and styling child controls.

Here is a good start, you'll need to scroll down to the CSS part.