SKMC.UI/SKMC.UI.DesignApp/App.xaml

<prism:PrismApplication 
             x:Class="SKMC.UI.DesignApp.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:local="clr-namespace:SKMC.UI.DesignApp"
             xmlns:prism="http://prismlibrary.com/">
    <prism:PrismApplication.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <ResourceDictionary Source="pack://application:,,,/SKMC.UI;component/Themes/Dark.xaml" />
                <ResourceDictionary Source="pack://application:,,,/SKMC.UI;component/FrameWork.xaml" />
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </prism:PrismApplication.Resources>
</prism:PrismApplication>