how to apply CSS class to MVCcontrib grid

In Razor view:
@Html.Grid(
...
    ).Attributes(@class => "ContribGrid")

In css file:
.ContribGrid th
{
   background: red;
}

ASP.NET MVC 4 Developer Preview: What’s New

http://www.sitepoint.com/asp-net-mvc-4-developer-preview-whats-new/