Which css versions are supported in chm files?

Question

I am writing a stylesheet to use with my Compiled Help files. It looks like CSS2 generally works, but I\'m not sure about CSS selectors like > and +

Answer 1

The HTML Help Viewer uses the layout engine components of Microsoft Internet Explorer (Shdocvw.dll hosting Mshtml.dll) to display Help topics.

http://msdn.microsoft.com/en-us/library/aa189109%28v=office.10%29.aspx

Which means: CSS version support is determined by which IE version is installed.