updated css3-compat.html file to remove the ':root' test since it is not widely supported by selectors engines and it was hiding important parts of the test, modified some bottom description test to reflect this change
updated css3-compat.html file to remove the ':root' test since it is not widely supported by selectors engines and it was hiding important parts of the test, modified some bottom description test to reflect this change

dperini/nwmatcher,dperini/nwmatcher,dperini/nwmatcher