How to dynamically generate CSS file from database in ASP.NET MVC - asp.net-mvc-3

Question

i was going through a post in stackoverflow and the link is Dynamically generate CSS file from database in ASP.NET MVC
here i am giving the full code and i like to know few thinks from the code.
I think the simplest way would be to add something like the following action method to a controller:
public class CssController : Controller
{
public ContentResult GetTheme()
{
var builder = new StringBuilder();
IDictionary<string, IDictionary<string, string>> css = new Dictionary<string, IDictionary<string, string>>();
/* Populate css object from the database */
foreach (var selector in css)
{
builder.Append(selector.Key);
builder.Append(" { ");
foreach (var entry in selector.Value)
{
builder.Append(string.Format("{0}: {1}; ", entry.Key, entry.Value));
}
builder.AppendLine("}");
}
return Content(builder.ToString(), "text/css");
}
}
Now in your page you can reference it like so:
<link href="<%: Url.RouteUrl(new { controller= "CssController", action = "GetCss" }) %>" rel="stylesheet" type="text/css" />
my question is what file name will show in href ?
the controller CssController & action method GetCss is writing string to out going stream so no file name should show in href....how this code will work?? please guide me to understand this catch......thanks