code not working in wpf

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WPF

i want to set border in xaml and want to use only style inwindows..
this is my code in app.XAML
but it is not working in window style property
also i use for grid..

<Style x:Key="SetBorder">
         <Setter Property="C>
             <Setter.Value>
                 <C>
                     <Border  BorderBrush="#FF101010" BorderThickness="5" CornerRadius="60,0,60,0" Width="1002" Height="643">
                         <Border.Background>
                             <LinearGradientBrush EndPoint="1,1" StartPoint="0,0">
                                 <GradientStop Color="#FFFDE6FF" Offset="0" />
                                 <GradientStop Color="cyan" Offset="0.4" />
                                 <GradientStop Color="Gray" Offset="1" />
                             </LinearGradientBrush>
                         </Border.Background>
                     </Border>
                 </C>
             </Setter.Value>
         </Setter>
     </Style>