STW-Reborn-Launcher/WpfApp6/App.xaml

<Application x:Class="WpfApp6.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:local="clr-namespace:WpfApp6"
             xmlns:ui="http://schemas.modernwpf.com/2019"
              StartupUri="MainWindow.xaml">
    <Application.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <ui:ThemeResources />
                <ui:XamlControlsResources />
                <!-- Other merged dictionaries here -->
            </ResourceDictionary.MergedDictionaries>
            <!-- Other app resources here -->
        </ResourceDictionary>
    </Application.Resources>
</Application>