PP/PPPISI52/App.xaml

<Application x:Class="PPPISI52.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:local="clr-namespace:PPPISI52"
             
                   StartupUri="Windows/AutorisationWindow.xaml">
    <Application.Resources>
        <!--Текст-->
        <Style TargetType="TextBlock">
            <Setter Property="FontFamily" Value="Comic Sans MS"/>
            <Setter Property="FontSize" Value="14"/>
        </Style>

        <!--Кнопка-->
        <Style TargetType="Button">
            <Style.Setters>
                <Setter Property="Background" Value="HotPink"/>
                <Setter Property="FontSize" Value="14"/>
                <Setter Property="Foreground" Value="White"/>
            </Style.Setters>
            <Style.Triggers>
                <Trigger Property="IsMouseOver" Value="True">
                    <Setter Property="Foreground" Value="White"/>
                    <Setter Property="Background" Value="HotPink"/>
                </Trigger>
            </Style.Triggers>
        </Style>
    </Application.Resources>
</Application>