App.xaml

<Application x:Class="Page_Navigation_App.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:local="clr-namespace:Page_Navigation_App"
             StartupUri="MainWindow.xaml">
    
    <Application.Resources>

        <ResourceDictionary>

            <ResourceDictionary.MergedDictionaries>

                <ResourceDictionary Source="Styles/Page.xaml" />
                <ResourceDictionary Source="Styles/Image.xaml" />
                <ResourceDictionary Source="Styles/Text.xaml" />
                <ResourceDictionary Source="Styles/Button.xaml" />
                <ResourceDictionary Source="Utilities/DataTemplate.xaml" />

            </ResourceDictionary.MergedDictionaries>
            
        </ResourceDictionary>

    </Application.Resources>
    
</Application>