Hmm... looks like it's the Html extension methods conflicting: System.Web.Mvc.HtmlHelper
vs ServiceStack.Html.HtmlHelper
They overlap and generally play nice but you may need to specify the fully qualified name... now I'd normally suggest this:
@ServiceStack.Html.HtmlHelper
However, bundler is not located within HtmlHelper. It's in a separate Bundle.cs file that happens to reside within the ServiceStack.Html namespace. So what you really want is this:
@ServiceStack.Html.Bundler.RenderCssBundle()
As a final check, you may want to make sure you reference ServiceStack.Html in your web.config or add a @using ServiceStack.Html
at the top of your view. Here is where the reference goes in your web.config:
<system.web.webPages.razor>
<host stuff="..." />
<pages stuff="...">
<namespaces>
<!-- ... -->
<add namespace="ServiceStack.Html" />
<!-- ... -->
</namespaces>
</pages>
</host>
</system.web.webPages.razor>