Kindly refer following link for
CSS3
http://madskristensen.net/post/Get-latest-CSS-3-support-in-Visual-Studio-2010.aspx .
For
HTML5 suppor t, you have to install VS 2010 SP1.
After installing SP1,Go to Tools -> Options, and then select Text Editor -> HTML -> Validation. You should now be able to select HTML5 or XHTML5 as the target schema.
Rajesh Patel
MCPD,MS
Brainbench (Asp.Net 4.0 and CSS 3.0)