HandyControl/src/Shared/HandyControl_Shared/Themes/Styles/Base/SideMenuBaseStyle.xaml

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                    xmlns:controls="clr-namespace:HandyControl.Controls">

    <Style x:Key="SideMenuBaseStyle" TargetType="controls:SideMenu">

    </Style>

</ResourceDictionary>