R29/WpfApp29/UserWindow.xaml

<Window x:Class="WpfApp29.UserWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfApp29" xmlns:usercontrols="clr-namespace:WpfApp29.UserControls"
        mc:Ignorable="d"
        Title="UserWindow" Height="450" Width="800">
    <Grid>
        <Grid.Background>
            <ImageBrush ImageSource="/bg.png"/>
        </Grid.Background>
        <Grid.RowDefinitions>
            <RowDefinition Height="80"></RowDefinition>
            <RowDefinition></RowDefinition>
        </Grid.RowDefinitions>
        <Border VerticalAlignment="Top" HorizontalAlignment="Center" Padding="7" BorderThickness="4" CornerRadius="10" BorderBrush="Black" Grid.RowSpan="2">
            <Border.Background>
                <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
                    <GradientStop Color="#FF2D2727"/>
                    <GradientStop Color="#FF7F1F1F" Offset="1"/>
                </LinearGradientBrush>
            </Border.Background>
            <WrapPanel Height="50" HorizontalAlignment="Center">
                <Button Content="Главное меню" Width="150" Height="50" FontSize="18" Command="{Binding CommandGoMainMenu}"></Button>
                <Button Content="Мой аккаунт" Width="150" Height="50" FontSize="18" Command="{Binding CommandGoAccount}"></Button>
                <Button Content="Пользователи" Width="150" Height="50" FontSize="18" Command="{Binding CommandGoUserList}"></Button>
                <Button Content="Выйти" Width="150" Height="50" FontSize="18" Command="{Binding CommandGoLoginWindow}"></Button>
            </WrapPanel>
        </Border>
        <Frame Name="FramePages" Grid.Row="2"></Frame>
    </Grid>
</Window>