How to give alternative row background color in PivotGrid

<Style x:Key="valStyle" TargetType="{x:Type syncfusion:PivotGridTemplateCell}">
                <Setter Property="MinHeight" Value="25"/>
                <Setter Property="Template">
                    <Setter.Value>
                        <ControlTemplate TargetType="{x:Type syncfusion:PivotGridTemplateCell}">
                            <StackPanel  Grid.Column="1" Orientation="Horizontal" Background="{Binding ElementName=pivotGrid1, Converter={StaticResource backcolor}, NotifyOnTargetUpdated=True}">
                                 <!--Image block-->
                                <Image Margin="2,4,1,0" Grid.Column="1" Source="{Binding ElementName=pivotGrid1, Converter={StaticResource imgConverter}, NotifyOnTargetUpdated=True}" TargetUpdated="Image_TargetUpdated" VerticalAlignment="Top" HorizontalAlignment="Center">
                                    <Image.Style>
                                        <Style TargetType="{x:Type Image}">
                                        </Style>
                                    </Image.Style>
                                </Image>
 
                                <TextBlock Grid.Column="1" Margin="3,4,2,0"  
                                           Text="{Binding Path=Text, RelativeSource={RelativeSource TemplatedParent}}"  
                                           TextWrapping="Wrap"
                                           VerticalAlignment="Top" FontFamily="Segoe UI"  FontSize="12"  TargetUpdated="Image_TargetUpdated"
                                           />
                            </StackPanel>
                        </ControlTemplate>
                    </Setter.Value>
                </Setter>
            </Style>

class BackColorConverter : IValueConverter
    {
 
        Brush brush = Brushes.White;
        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
 
            Syncfusion.Windows.Controls.PivotGrid.PivotGridControl pivotGrid = value as Syncfusion.Windows.Controls.PivotGrid.PivotGridControl;
            int rowIndex = MainWindow.rowIdex;
            int colIndex = MainWindow.colIndex;
                
                if (rowIndex % 2 == 0)
                {
                    brush = Brushes.Pink;
                    return brush;
                }
                else
                {
                    if (MainWindow.colIndex == -1 && MainWindow.rowIdex == -1)
                    {
                        brush = Brushes.Pink;
                    }
                    else
                    brush = Brushes.Red;
                }
            
            return brush;
 
 
        }
 
        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            throw new NotImplementedException();
        }
 
    }