collaborativePlatform/CollaborativePlatformProject/App.xaml

<Application x:Class="CollaborativePlatformProject.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:local="clr-namespace:CollaborativePlatformProject"
             StartupUri="MainWindow.xaml">
    <Application.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <ResourceDictionary Source="pack://application:,,,/LayUI.Wpf;component/Themes/Default.xaml" />
                <ResourceDictionary Source="pack://application:,,,/HandyControl;component/Themes/SkinDefault.xaml" />
                <ResourceDictionary Source="pack://application:,,,/HandyControl;component/Themes/Theme.xaml" />
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Application.Resources>
</Application>