bib_Talk_Chatprogramm/bibtalk/bib-talk/MainWindow.xaml

<Window x:Class="bib_talk.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"
        mc:Ignorable="d"
        Title="MainWindow" 
        Height="700" 
        Width="1000"
        WindowStyle="None"
        AllowsTransparency="True"
        Background="Transparent"
        WindowStartupLocation="CenterScreen" ResizeMode="NoResize">
    <Window.Resources>
        <Style x:Key="InvisibleButtonStyle" TargetType="Button">
            <Setter Property="Background" Value="Transparent"/>
            <Setter Property="BorderBrush" Value="Transparent"/>
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="Button">
                        <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
            <Setter Property="OverridesDefaultStyle" Value="True"/>
            <Style.Triggers>
                <Trigger Property="IsMouseOver" Value="True">
                    <Setter Property="Background" Value="Transparent"/>
                    <Setter Property="BorderBrush" Value="Transparent"/>
                </Trigger>
                <Trigger Property="IsPressed" Value="True">
                    <Setter Property="Background" Value="Transparent"/>
                    <Setter Property="BorderBrush" Value="Transparent"/>
                </Trigger>
            </Style.Triggers>
        </Style>
        <Style x:Key="NoHoverButtonStyle" TargetType="Button">
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="Button">
                        <Border Background="{TemplateBinding Background}"
                            BorderBrush="{TemplateBinding BorderBrush}"
                            BorderThickness="{TemplateBinding BorderThickness}"
                            Padding="{TemplateBinding Padding}">
                            <ContentPresenter HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
                                          VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
                        </Border>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </Window.Resources>

    <Border CornerRadius="15" BorderThickness="20" BorderBrush="#FF282828">
        <Grid Margin="-10,-10,-10,-10" Background="#FF282828">
            <!-- Draggable Area -->
            <Grid VerticalAlignment="Top" Height="45" Background="Transparent" MouseLeftButtonDown="DraggableArea_MouseLeftButtonDown" Margin="0,-21,0,0">

            </Grid>
            <!-- Close Button -->
            <Button Style="{StaticResource InvisibleButtonStyle}"
                    Width="30" 
                    Height="30" 
                    VerticalAlignment="Top" 
                    HorizontalAlignment="Right" 
                    Margin="0,0,0,0" 
                    Click="CloseButton_Click">
                <TextBlock Text="❌" 
                           FontSize="20"
                           Foreground="White" 
                           FontWeight="Bold" 
                           HorizontalAlignment="Center" 
                           VerticalAlignment="Center"/>
            </Button>
            <TextBlock HorizontalAlignment="Left" x:Name="loggedinuser" Margin="32,11,0,0" TextWrapping="Wrap" Text="xxxx" VerticalAlignment="Top" Height="22" Width="146" Foreground="White"/>
            <ListBox x:Name="onlineUsersListBox" Margin="32,60,760,440" d:ItemsSource="{d:SampleData ItemCount=5}" Background="#FF323134" BorderBrush="{x:Null}">
                <ListBox.ItemTemplate>
                    <DataTemplate>
                        <StackPanel Orientation="Horizontal">
                            <TextBlock Text="{Binding Username}" FontWeight="Bold" Margin="5" Foreground="#FF6332A0"/>
                            <Ellipse Width="10" Height="10" Fill="Green" Margin="5"/>
                        </StackPanel>
                    </DataTemplate>
                </ListBox.ItemTemplate>
            </ListBox>

            <ListBox x:Name="chatlistbox" Margin="244,60,44,105" d:ItemsSource="{d:SampleData ItemCount=5}" Background="#FF323134" BorderBrush="{x:Null}" Foreground="#FF6332A0" ScrollViewer.VerticalScrollBarVisibility="Hidden" ScrollViewer.HorizontalScrollBarVisibility="Hidden">
                <ListBox.ItemTemplate>
                    <DataTemplate>
                        <StackPanel Margin="5">
                            <TextBlock  Text="{Binding Username}" FontWeight="Bold" FontSize="20"/>
                            <TextBlock Text="{Binding Timestamp, StringFormat='{}{0:yyyy-MM-dd HH:mm:ss}'}" Foreground="Gray"/>
                            <TextBlock TextWrapping="Wrap" Text="{Binding Text}" FontSize="16"/>

                        </StackPanel>

                    </DataTemplate>

                </ListBox.ItemTemplate>

            </ListBox>
            
            <TextBox
                         x:Name="messageBOX"
                         Height="30"
                         FontSize="20"
                         BorderBrush="Transparent"
                         Margin="244,601,154,49"
                         Background="#FF323134"
                         Foreground="White"
                         SelectionBrush="#FF6332A0"/>
            <Button x:Name="weiterbutton" Click="send_Click" Content="Weiter" Foreground="White"  Background="#FF6332A0" BorderThickness="0" Margin="831,602,44,50" BorderBrush="{x:Null}" Style="{StaticResource NoHoverButtonStyle}" RenderTransformOrigin="0.279,0.633"/>


        </Grid>
    </Border>
</Window>