Server Error in '/' Application.

Using themed css files requires a header control on the page. (e.g. <head runat="server" />).

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.InvalidOperationException: Using themed css files requires a header control on the page. (e.g. <head runat="server" />).

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:


[InvalidOperationException: Using themed css files requires a header control on the page. (e.g. <head runat="server" />).]
   System.Web.UI.PageTheme.SetStyleSheet() +3692104
   System.Web.UI.Page.OnInit(EventArgs e) +11860626
   System.Web.UI.Control.InitRecursive(Control namingContainer) +166
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1598


Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.7.4087.0