Demka_kur/MainWindow.axaml

<Window xmlns="https://github.com/avaloniaui"
        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"
        mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
        x:Class="Demka_Snova_1.MainWindow"
            Title="Вход в систему" 
            Width="800" 
            Height="1200"> 
        <StackPanel Margin="10"> 
            <TextBox x:Name="UsernameTextBox" Watermark="Логин" /> 
            <StackPanel Orientation="Horizontal"> 
                <TextBox x:Name="PasswordTextBox" Watermark="Пароль" PasswordChar="*" /> 
                <Button x:Name="TogglePasswordButton" Content="👁" Margin="0,5, 0,0" Click="TogglePasswordButton_Click" /> 
            </StackPanel> 
            <Button x:Name="LoginButton" Content="Войти" Margin="0,10" Click="LoginButton_Click" /> 
        </StackPanel> 
    </Window>