Who says everything works? I just noticed that when I ran my ASP.NET app in the debugger the nth-child applied correctly. When I browsed in IE to the live site on my web server none of the nth-child applied and it all looked dreadful. After 30 minutes of looking in the F12 inspector and looking for other weird IIS and environmental problems I ran a search and finally stumbled across the post below in the noise. Like him, I was tricked into thinking it was my fault. This is a classic example of how brittle things are getting, with subtle and devious interdependencies between components.
Greg For some reason I cannot fathom, IE9 defaults to compatibility mode for looking at intranet sites, or an HTML page stored as a file on a PC. Compatibility mode means 'render stuff like a dumb old browser'. This means that when you're designing stuff for a website and you try to preview from your favourite IDE in IE9, none of the CSS3 stuff works. You have to click on Tools ->' compatibility view settings' in the IE9 menu and then unclick the pesky checkbox that says 'display interanet sites in compatibility view'. From then on the wretched browser works like any sane browser such as Safari. Why did they do it? Heaven only knows, but it has taken me ages to discover this simple fix due to the fact that I kept blaming my code.
