Microsoft released “Web Standards Update for Microsoft Visual Studio 2010 SP1”. which will add HTML5 and CSS3 support to Visual studio 2010. This update will support Visual Web Developer Express 2010 SP1 also.
This update will add
HTML5 support up-to-date
CSS 3 support
Read more about Web Standards Update for Microsoft Visual Studio 2010 SP1, and download it from here
If you have not installed Service Pack 1 of Visual Studio 2010 you can get it from here.