css not rendered when using asp.net development server

Hello.

Here's my problem.

I have authentication declared as the following.

<authentication mode="Forms">
   <forms name="ProjectX" loginUrl="/ProjectX.WebForms/login.aspx" protection="All" timeout="240" slidingExpiration="true" path="/"/>
  </authentication>

  <authorization>
   <deny users="?"/>
  </authorization>

 When I deploy my application on IIS 5.1, no problem rendering the login page.

However, when I open the page with asp.net development server, the css style sheet is not rendered at all. css file(ProjectX.css) is placed on the top level along with the login page.

I put the following code to Web.config but the problem still persists.

 <location allowOverride="true" path="ProjectX.css&quo ...