new/Views/RegistrationView.axaml

<UserControl xmlns="https://github.com/avaloniaui"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
			 xmlns:vm="using:YtYtAvalonia.ViewModels"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
             mc:Ignorable="d" d:DesignWidth="1920" d:DesignHeight="1080"
             x:Class="YtYtAvalonia.Views.RegistrationView"
			 x:DataType="vm:MainWindowViewModel">
	<Grid>
		<StackPanel HorizontalAlignment="Center" VerticalAlignment="Center">

			<StackPanel.Styles>
				<Style Selector="TextBox">
					<Setter Property="Background" Value="#F8FDFF"></Setter>
					<Setter Property="BorderBrush" Value="#008BC7"></Setter>
					<Setter Property="CornerRadius" Value="8"></Setter>
					<Setter Property="BorderThickness" Value="2"></Setter>
					<Setter Property="FontSize" Value="13"></Setter>
					<Setter Property="FontFamily" Value="Roboto"></Setter>
				</Style>
				<Style Selector="ComboBox">
					<Setter Property="Background" Value="#F8FDFF"></Setter>
					<Setter Property="BorderBrush" Value="#008BC7"></Setter>
					<Setter Property="CornerRadius" Value="8"></Setter>
					<Setter Property="BorderThickness" Value="2"></Setter>
					<Setter Property="FontSize" Value="13"></Setter>
					<Setter Property="FontFamily" Value="Roboto"></Setter>
					<Setter Property="Foreground" Value="Gray"></Setter>
				</Style>
				<Style Selector="Button:pointerover /template/ ContentPresenter">
					<Setter Property="Background" Value="#2B95BD"></Setter>
				</Style>
				<Style Selector="Button.Login:pointerover /template/ ContentPresenter">
					<Setter Property="Background" Value="White"></Setter>
					<Setter Property="Foreground" Value="#2B95BD"></Setter>
				</Style>
			</StackPanel.Styles>

			<TextBlock HorizontalAlignment="Center" Margin="0 0 0 30" FontFamily="Roboto" FontSize="25" FontWeight="Bold">Регистрация</TextBlock>
			<TextBox Text="{Binding RegVM.CurrentUser.Login}" Watermark="Логин" Width="360" FontSize="13" Margin="0 0 0 10" ></TextBox>
			<TextBox Text="{Binding RegVM.CurrentUser.Password}" Watermark="Пароль" PasswordChar="•" Width="360" ></TextBox>
			<TextBlock Margin="0 25 0 0"  FontFamily="Roboto" FontSize="14">Личные данные:</TextBlock>
			<TextBox Text="{Binding RegVM.CurrentUser.Surname}" Watermark="Фамилия" Width="360" FontSize="13" Margin="0 10 0 10" ></TextBox>
			<TextBox Text="{Binding RegVM.CurrentUser.Name}" Watermark="Имя" Width="360" FontSize="13" Margin="0 0 0 10" ></TextBox>
			<TextBox Text="{Binding RegVM.CurrentUser.Patronymic}" Watermark="Отчество" Width="360" FontSize="13" Margin="0 0 0 25" ></TextBox>
			<TextBlock Margin="0 0 0 10" FontFamily="Roboto" FontSize="14">Дата рождения:</TextBlock>
			<StackPanel Spacing="10" Orientation="Horizontal" HorizontalAlignment="Center">
				<DatePicker SelectedDate="{Binding RegVM.Birthday}" Width="360" CornerRadius="8" Background="#F8FDFF" BorderBrush="#008BC7" BorderThickness="2" FontFamily="Roboto"></DatePicker>
			</StackPanel>
			<TextBox Text="{Binding RegVM.CurrentUser.Email}" Watermark="Элетронная почта" Width="360" FontSize="13" Margin="0 25 0 10" ></TextBox>
			<TextBox Text="{Binding RegVM.CurrentUser.Phonenumber}" Watermark="Номер телефона" Width="360" FontSize="13" Margin="0 0 0 25" ></TextBox>
			<Button HorizontalAlignment="Center" Margin="0 20 0 10" Width="230" Height="45" CornerRadius="10" Background="#38BFF2" Command="{Binding $parent[Window].((vm:MainWindowViewModel)DataContext).SaveData}">
				<TextBlock HorizontalAlignment="Center" VerticalAlignment="Center" FontFamily="Roboto" FontSize="16" FontWeight="DemiBold" Foreground="White">Зарегистироваться</TextBlock>
			</Button>
			<StackPanel HorizontalAlignment="Center" Orientation="Horizontal">
				<TextBlock Text="Уже есть аккаунт?" FontFamily="Roboto" FontSize="14" VerticalAlignment="Center"></TextBlock>
				<Button Classes="Login" FontFamily="Roboto" FontSize="14" Background="White" Command="{Binding $parent[Window].((vm:MainWindowViewModel)DataContext).LoadLoginView}">Войти</Button>
			</StackPanel>
		</StackPanel>
	</Grid>
</UserControl>