PR13AndMore/MainWindow.xaml

<Window x:Class="PR13_Kazak.MainWindow"
        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:PR13_Kazak"
        mc:Ignorable="d"
        Title="MainWindow" Height="376" Width="901">
    <Grid>
        <Grid HorizontalAlignment="Left" Height="335" Margin="10,10,0,0" VerticalAlignment="Top" Width="883">
            <Grid.RowDefinitions>
                <RowDefinition Height="40*"/>
                <RowDefinition Height="235*"/>
                <RowDefinition Height="40*"/>
            </Grid.RowDefinitions>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="880*"/>
                <ColumnDefinition Width="3*"/>
                <ColumnDefinition Width="0*"/>
                <ColumnDefinition Width="0*"/>
            </Grid.ColumnDefinitions>
            <Rectangle Fill="#FFF4F4F5" Grid.Row="2" Stroke="Black" StrokeThickness="0" RenderTransformOrigin="0.499,-0.146" Margin="0,0,1,0"/>
            <Button Content="Назад" HorizontalAlignment="Left" Margin="10,10,0,0" VerticalAlignment="Top" Width="75" Height="20" Name="ButtonBack"/>
            <Frame x:Name="MainFrame" Source="Pages/AuthPage.xaml" Grid.Row="1" Navigated="MainFrame_OnNavigated"/>
        </Grid>

    </Grid>
</Window>