UP_WPF/UP_Venediktov/Pages/Avtorization.xaml

<Page x:Class="UP_Venediktov.Pages.Avtorization"
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
      xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
      xmlns:local="clr-namespace:UP_Venediktov.Pages"
      mc:Ignorable="d" 
      d:DesignHeight="450" d:DesignWidth="800"
      Title="Avtorization"
      FontFamily="Comic Sans MS">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="0.2*"/>
            <RowDefinition/>
            <RowDefinition Height="0.2*"/>
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition />
            <ColumnDefinition Width="2*"/>
            <ColumnDefinition/>
        </Grid.ColumnDefinitions>

        <Border BorderBrush="#76E383" BorderThickness="3" CornerRadius="15" Grid.Row="1" Grid.Column="1" Margin="40">
            <StackPanel Orientation="Vertical" VerticalAlignment="Center">
                <TextBlock Text="Авторизация" HorizontalAlignment="Center" FontWeight="Bold" Grid.Column="1" Grid.Row="0"/>
                <GroupBox Header="Логин" Height="42" Style="{StaticResource GBSt}">
                <TextBox Name="Login" DataContext="Логин" Style="{StaticResource TBSt}"/>
                </GroupBox>
                <GroupBox Header="Пароль" Style="{StaticResource GBSt}">
                    <PasswordBox Name="Password" DataContext="Пароль" Style="{StaticResource PSBSt}" />
                </GroupBox>
                <Button Name="Sign" Content="Войти" Style="{StaticResource BtnSt}" Margin="0,20,0,0" />
            </StackPanel>
        </Border>
        <Button Name="Mode" Content="Режим просмотра"  Style="{StaticResource BtnSt}" Grid.Column="1" Grid.Row="2" Click="Check_Click"/>
    </Grid>
</Page>