shavrinwpf/ComputerShopWpf/Views/LoginWindow.xaml

<Window x:Class="ComputerShopWpf.Views.LoginWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="Вход в систему"
        Height="460"
        Width="560"
        MinHeight="440"
        MinWidth="540"
        WindowStartupLocation="CenterScreen"
        ResizeMode="CanMinimize">
    <Grid Background="{StaticResource BackgroundBrush}">
        <Border Width="430"
                Padding="34"
                Background="{StaticResource PanelBrush}"
                BorderBrush="{StaticResource BorderBrush}"
                BorderThickness="1"
                VerticalAlignment="Center"
                HorizontalAlignment="Center">
            <StackPanel>
                <TextBlock Text="Продажа компьютерной техники"
                           FontSize="24"
                           FontWeight="SemiBold"
                           TextAlignment="Center"
                           TextWrapping="Wrap"
                           Margin="0,0,0,24"/>

                <TextBlock Text="Логин"/>
                <TextBox x:Name="LoginTextBox"/>

                <TextBlock Text="Пароль"/>
                <PasswordBox x:Name="UserPasswordBox"/>

                <TextBlock x:Name="ErrorTextBlock"
                           Foreground="{StaticResource ErrorBrush}"
                           TextWrapping="Wrap"
                           MinHeight="48"
                           Margin="0,6,0,10"/>

                <Button x:Name="LoginButton"
                        Content="Войти"
                        Height="38"
                        HorizontalAlignment="Stretch"
                        Click="LoginButton_Click"/>
            </StackPanel>
        </Border>
    </Grid>
</Window>