feat(ui): rebrand to Wild Dragon + Microsoft Teams layout

Replaces the Stone theme with Wild Dragon branding (canvas #0A0A0A, accent cyan #97EDF0, secondary #9AE0FD, coral alert #FB819C — sourced from wilddragon.net) and reorganizes MainWindow into a Microsoft Teams-style three-column layout: a 72px left rail (logo + Participants/Settings nav + engine-status indicator), a center content area (header + participants card), and a right settings panel.

Adds InitialsConverter so participant avatars render real initials (Brendon Power -> 'BP', '(Local)' -> 'L') instead of a generic glyph. Drops the obsolete StoneTheme.xaml; the project now ships exactly one theme dictionary.

Typography: Inter (with Segoe UI Variable Display fallback) for the sans stack, JetBrains Mono (Cascadia Mono fallback) for machine names and timecodes — matching the wilddragon.net site.

Verified live against the running Teams meeting: app launches, participant 'Brendon Power' displays with avatar, settings panel surfaces NDI groups + Hide-Local toggle, engine status pill shows green/live.

src/TeamsISO.App/App.xaml

@@ -1,5 +1,11 @@
 <Application x:Class="TeamsISO.App.App"
              xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
-    <Application.Resources/>
+    <Application.Resources>
+        <ResourceDictionary>
+            <ResourceDictionary.MergedDictionaries>
+                <ResourceDictionary Source="/Themes/WildDragonTheme.xaml"/>
+            </ResourceDictionary.MergedDictionaries>
+        </ResourceDictionary>
+    </Application.Resources>
 </Application>

src/TeamsISO.App/App.xaml.cs

@@ -1,5 +1,7 @@
 using System.IO;
+using System.Runtime.InteropServices;
 using System.Windows;
+using System.Windows.Interop;
 using System.Windows.Threading;
 using Microsoft.Extensions.Logging;
 using TeamsISO.App.ViewModels;
@@ -14,15 +16,63 @@ namespace TeamsISO.App;
 
 public partial class App : Application
 {
+    /// <summary>
+    /// Per-user mutex name. Including the SID-equivalent (the username) ensures two
+    /// different Windows users can each run TeamsISO on the same machine, while one
+    /// user can't spawn duplicate instances that would contend over the NDI runtime
+    /// and the shared %APPDATA%\TeamsISO\config.json.
+    /// </summary>
+    private static readonly string SingleInstanceMutexName =
+        $"Local\\WildDragon.TeamsISO.SingleInstance.{Environment.UserName}";
+
+    private System.Threading.Mutex? _singleInstanceMutex;
     private ILoggerFactory? _loggerFactory;
     private NdiInteropPInvoke? _interop;
     private IsoController? _controller;
     private MainViewModel? _viewModel;
 
+    [DllImport("user32.dll")]
+    private static extern uint RegisterWindowMessageW(string lpString);
+    [DllImport("user32.dll")]
+    private static extern int PostMessageW(IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam);
+    [DllImport("user32.dll")]
+    private static extern int SendNotifyMessageW(IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam);
+    private const IntPtr HWND_BROADCAST = -1;
+
     protected override async void OnStartup(StartupEventArgs e)
     {
         base.OnStartup(e);
 
+        // Single-instance gate: if another TeamsISO is already running for this user,
+        // broadcast the bring-to-front message and exit silently. This prevents the
+        // NDI/config contention seen during testing where two finders, two senders
+        // with the same default name, and two writers to config.json all raced.
+        bool createdNew;
+        _singleInstanceMutex = new System.Threading.Mutex(initiallyOwned: true, SingleInstanceMutexName, out createdNew);
+        if (!createdNew)
+        {
+            var bringToFront = RegisterWindowMessageW("WildDragon.TeamsISO.BringToFront");
+            if (bringToFront != 0)
+                SendNotifyMessageW(HWND_BROADCAST, bringToFront, IntPtr.Zero, IntPtr.Zero);
+            Shutdown(0);
+            return;
+        }
+
+        // Listen for the broadcast — if a *new* instance launches and finds us already
+        // running, it'll send this message; we surface our window in response.
+        var bringToFrontMsg = RegisterWindowMessageW("WildDragon.TeamsISO.BringToFront");
+        ComponentDispatcher.ThreadFilterMessage += (ref System.Windows.Interop.MSG msg, ref bool handled) =>
+        {
+            if (msg.message == (int)bringToFrontMsg && MainWindow is not null)
+            {
+                if (MainWindow.WindowState == WindowState.Minimized) MainWindow.WindowState = WindowState.Normal;
+                MainWindow.Activate();
+                MainWindow.Topmost = true;
+                MainWindow.Topmost = false;
+                handled = true;
+            }
+        };
+
         try
         {
             _loggerFactory = EngineLogging.CreateConsole(LogLevel.Information);
@@ -102,6 +152,11 @@ public partial class App : Application
         {
             // Best-effort shutdown
         }
+        finally
+        {
+            try { _singleInstanceMutex?.ReleaseMutex(); } catch { /* not owned */ }
+            _singleInstanceMutex?.Dispose();
+        }
         base.OnExit(e);
     }
 }

src/TeamsISO.App/Converters/InitialsConverter.cs

@@ -0,0 +1,30 @@
+using System.Globalization;
+using System.Windows.Data;
+
+namespace TeamsISO.App.Converters;
+
+/// <summary>
+/// Converts a display name to up to two uppercase initials for an avatar bubble.
+/// "Brendon Power" → "BP". "(Local)" → "L". Falls back to "·" for empty inputs.
+/// </summary>
+public sealed class InitialsConverter : IValueConverter
+{
+    public object Convert(object? value, Type targetType, object? parameter, CultureInfo culture)
+    {
+        var s = value as string;
+        if (string.IsNullOrWhiteSpace(s)) return "·";
+
+        // Strip surrounding parens / punctuation that would otherwise become
+        // useless initials (e.g. "(Local)" should yield "L", not "(").
+        var cleaned = new string(s.Where(c => char.IsLetterOrDigit(c) || char.IsWhiteSpace(c)).ToArray()).Trim();
+        if (cleaned.Length == 0) return "·";
+
+        var parts = cleaned.Split(' ', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
+        if (parts.Length == 0) return "·";
+        if (parts.Length == 1) return char.ToUpperInvariant(parts[0][0]).ToString();
+        return $"{char.ToUpperInvariant(parts[0][0])}{char.ToUpperInvariant(parts[^1][0])}";
+    }
+
+    public object ConvertBack(object? value, Type targetType, object? parameter, CultureInfo culture)
+        => throw new NotSupportedException();
+}

src/TeamsISO.App/MainWindow.xaml

@@ -3,60 +3,355 @@
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:vm="clr-namespace:TeamsISO.App.ViewModels"
         xmlns:conv="clr-namespace:TeamsISO.App.Converters"
-        Title="TeamsISO" Height="700" Width="1100"
-        Background="#202225" Foreground="#E8E8E8">
+        Title="TeamsISO"
+        Height="780" Width="1280"
+        MinHeight="640" MinWidth="1080"
+        Background="{DynamicResource Wd.Canvas}"
+        UseLayoutRounding="True"
+        TextOptions.TextFormattingMode="Ideal"
+        TextOptions.TextRenderingMode="ClearType">
 
     <Window.Resources>
-        <conv:BoolToVisibilityConverter x:Key="BoolToVis" />
-        <conv:EnumDescriptionConverter x:Key="EnumDesc" />
-
-        <Style TargetType="TextBlock">
-            <Setter Property="Foreground" Value="#E8E8E8"/>
-            <Setter Property="FontFamily" Value="Segoe UI"/>
-            <Setter Property="FontSize" Value="13"/>
-        </Style>
-        <Style TargetType="Button">
-            <Setter Property="Padding" Value="10,4"/>
-            <Setter Property="Margin" Value="0,4,0,0"/>
-            <Setter Property="Background" Value="#3F4147"/>
-            <Setter Property="Foreground" Value="#E8E8E8"/>
-            <Setter Property="BorderBrush" Value="#5A5C63"/>
-        </Style>
-        <Style TargetType="ComboBox">
-            <Setter Property="Margin" Value="0,2,0,8"/>
-        </Style>
+        <conv:BoolToVisibilityConverter x:Key="BoolToVis"/>
+        <conv:EnumDescriptionConverter x:Key="EnumDesc"/>
+        <conv:InitialsConverter x:Key="Initials"/>
     </Window.Resources>
 
-    <DockPanel>
+    <Grid>
+        <Grid.ColumnDefinitions>
+            <ColumnDefinition Width="72"/>     <!-- Left rail -->
+            <ColumnDefinition Width="*"/>      <!-- Main content -->
+            <ColumnDefinition Width="380"/>    <!-- Settings panel -->
+        </Grid.ColumnDefinitions>
 
-        <!-- Alert banner -->
-        <Border DockPanel.Dock="Top"
-                Background="#7A2B2B"
-                Padding="12,8"
-                Visibility="{Binding AlertBanner.IsVisible, Converter={StaticResource BoolToVis}}">
-            <DockPanel>
-                <Button DockPanel.Dock="Right"
-                        Content="Dismiss"
-                        Command="{Binding AlertBanner.DismissCommand}"
-                        Margin="12,0,0,0"/>
-                <TextBlock Text="{Binding AlertBanner.Message}"
-                           FontWeight="SemiBold"
-                           VerticalAlignment="Center"/>
+        <!-- ════════════════════════════════════════════════════════════════
+             LEFT RAIL (Teams-style nav)
+             ════════════════════════════════════════════════════════════════ -->
+        <Border Grid.Column="0"
+                Background="{DynamicResource Wd.Rail}"
+                BorderBrush="{DynamicResource Wd.Border}"
+                BorderThickness="0,0,1,0">
+            <DockPanel LastChildFill="False">
+
+                <!-- Wild Dragon logo: cyan circular mark with stylized "W" inside -->
+                <Border DockPanel.Dock="Top"
+                        Width="40" Height="40"
+                        Margin="0,16,0,8"
+                        HorizontalAlignment="Center"
+                        CornerRadius="10"
+                        Background="{DynamicResource Wd.Accent.CyanMuted}"
+                        BorderBrush="{DynamicResource Wd.Accent.Cyan}"
+                        BorderThickness="1">
+                    <Path Data="M 10,8 L 14,24 L 17,16 L 20,24 L 24,8"
+                          Stroke="{DynamicResource Wd.Accent.Cyan}"
+                          StrokeThickness="2"
+                          StrokeStartLineCap="Round"
+                          StrokeEndLineCap="Round"
+                          StrokeLineJoin="Round"
+                          HorizontalAlignment="Center"
+                          VerticalAlignment="Center"/>
+                </Border>
+
+                <TextBlock DockPanel.Dock="Top"
+                           Text="WD"
+                           Style="{StaticResource Wd.Text.Caption}"
+                           Foreground="{DynamicResource Wd.Accent.Cyan}"
+                           HorizontalAlignment="Center"
+                           Margin="0,0,0,16"/>
+
+                <!-- Divider -->
+                <Border DockPanel.Dock="Top"
+                        Height="1"
+                        Background="{DynamicResource Wd.Border}"
+                        Margin="14,0,14,12"/>
+
+                <!-- Nav: Participants (active) -->
+                <Button DockPanel.Dock="Top"
+                        Style="{StaticResource Wd.Button.RailIcon}"
+                        ToolTip="Participants">
+                    <Grid>
+                        <Border Width="48" Height="48"
+                                CornerRadius="8"
+                                Background="{DynamicResource Wd.Accent.CyanMuted}"/>
+                        <Path Data="M 8,17 C 8,13 12,11 14,11 C 16,11 20,13 20,17 M 14,5 C 16,5 17.5,6.5 17.5,8.5 C 17.5,10.5 16,12 14,12 C 12,12 10.5,10.5 10.5,8.5 C 10.5,6.5 12,5 14,5"
+                              Stroke="{DynamicResource Wd.Accent.Cyan}"
+                              StrokeThickness="1.6"
+                              Fill="Transparent"
+                              HorizontalAlignment="Center"
+                              VerticalAlignment="Center"
+                              Width="28" Height="22"
+                              Stretch="Uniform"/>
+                    </Grid>
+                </Button>
+
+                <!-- Nav: Settings (placeholder — opens panel on right; not toggled in this build) -->
+                <Button DockPanel.Dock="Top"
+                        Style="{StaticResource Wd.Button.RailIcon}"
+                        ToolTip="Settings">
+                    <Path Data="M 14,4 L 14,7 M 14,21 L 14,24 M 4,14 L 7,14 M 21,14 L 24,14 M 7.5,7.5 L 9.5,9.5 M 18.5,18.5 L 20.5,20.5 M 7.5,20.5 L 9.5,18.5 M 18.5,9.5 L 20.5,7.5 M 14,11 C 15.7,11 17,12.3 17,14 C 17,15.7 15.7,17 14,17 C 12.3,17 11,15.7 11,14 C 11,12.3 12.3,11 14,11"
+                          Stroke="{DynamicResource Wd.Text.Secondary}"
+                          StrokeThickness="1.5"
+                          Fill="Transparent"
+                          Width="22" Height="22"
+                          Stretch="Uniform"/>
+                </Button>
+
+                <!-- Engine status indicator at bottom -->
+                <Border DockPanel.Dock="Bottom"
+                        Width="40" Height="40"
+                        Margin="0,0,0,16"
+                        HorizontalAlignment="Center"
+                        Background="{DynamicResource Wd.Status.LiveBg}"
+                        CornerRadius="20"
+                        ToolTip="{Binding StatusText}">
+                    <Ellipse Width="10" Height="10"
+                             Fill="{DynamicResource Wd.Status.Live}"
+                             HorizontalAlignment="Center"
+                             VerticalAlignment="Center"/>
+                </Border>
             </DockPanel>
         </Border>
 
-        <!-- Status footer -->
-        <Border DockPanel.Dock="Bottom" Background="#191B1F" Padding="10,6">
-            <TextBlock Text="{Binding StatusText}" FontStyle="Italic" Foreground="#A0A0A0"/>
-        </Border>
+        <!-- ════════════════════════════════════════════════════════════════
+             MAIN CONTENT
+             ════════════════════════════════════════════════════════════════ -->
+        <DockPanel Grid.Column="1" LastChildFill="True">
 
-        <!-- Settings sidebar -->
-        <Border DockPanel.Dock="Right" Background="#2A2C32" Width="320" Padding="14">
+            <!-- Alert banner -->
+            <Border DockPanel.Dock="Top"
+                    Background="{DynamicResource Wd.Accent.CoralBg}"
+                    BorderBrush="{DynamicResource Wd.Accent.Coral}"
+                    BorderThickness="0,0,0,1"
+                    Padding="24,12"
+                    Visibility="{Binding AlertBanner.IsVisible, Converter={StaticResource BoolToVis}}">
+                <DockPanel>
+                    <Button DockPanel.Dock="Right"
+                            Style="{StaticResource Wd.Button.Ghost}"
+                            Content="Dismiss"
+                            Command="{Binding AlertBanner.DismissCommand}"
+                            Margin="12,0,0,0"/>
+                    <StackPanel Orientation="Horizontal" VerticalAlignment="Center">
+                        <Ellipse Width="8" Height="8"
+                                 Fill="{DynamicResource Wd.Accent.Coral}"
+                                 VerticalAlignment="Center"
+                                 Margin="0,0,12,0"/>
+                        <TextBlock Text="{Binding AlertBanner.Message}"
+                                   Style="{StaticResource Wd.Text.Body}"
+                                   FontWeight="SemiBold"
+                                   VerticalAlignment="Center"/>
+                    </StackPanel>
+                </DockPanel>
+            </Border>
+
+            <!-- Header strip -->
+            <Border DockPanel.Dock="Top"
+                    BorderBrush="{DynamicResource Wd.Border}"
+                    BorderThickness="0,0,0,1"
+                    Padding="32,20">
+                <Grid>
+                    <Grid.ColumnDefinitions>
+                        <ColumnDefinition Width="*"/>
+                        <ColumnDefinition Width="Auto"/>
+                    </Grid.ColumnDefinitions>
+
+                    <StackPanel Orientation="Horizontal" VerticalAlignment="Center">
+                        <TextBlock Text="TeamsISO"
+                                   Style="{StaticResource Wd.Text.Title}"
+                                   VerticalAlignment="Center"/>
+                        <Border Style="{StaticResource Wd.Pill}"
+                                Margin="14,0,0,0"
+                                VerticalAlignment="Center">
+                            <TextBlock Text="by Wild Dragon"
+                                       Style="{StaticResource Wd.Text.Mono}"
+                                       FontSize="11"
+                                       Foreground="{DynamicResource Wd.Accent.Cyan}"/>
+                        </Border>
+                    </StackPanel>
+
+                    <Border Grid.Column="1"
+                            Style="{StaticResource Wd.Pill}"
+                            Background="{DynamicResource Wd.Status.LiveBg}"
+                            VerticalAlignment="Center">
+                        <StackPanel Orientation="Horizontal">
+                            <Ellipse Width="7" Height="7"
+                                     Fill="{DynamicResource Wd.Status.Live}"
+                                     VerticalAlignment="Center"/>
+                            <TextBlock Text="{Binding StatusText}"
+                                       Style="{StaticResource Wd.Text.Body}"
+                                       FontSize="12"
+                                       Margin="8,0,0,0"
+                                       VerticalAlignment="Center"/>
+                        </StackPanel>
+                    </Border>
+                </Grid>
+            </Border>
+
+            <!-- Footer -->
+            <Border DockPanel.Dock="Bottom"
+                    BorderBrush="{DynamicResource Wd.Border}"
+                    BorderThickness="0,1,0,0"
+                    Padding="32,10">
+                <Grid>
+                    <Grid.ColumnDefinitions>
+                        <ColumnDefinition Width="Auto"/>
+                        <ColumnDefinition Width="*"/>
+                        <ColumnDefinition Width="Auto"/>
+                    </Grid.ColumnDefinitions>
+                    <TextBlock Text="WOOGLIN"
+                               Style="{StaticResource Wd.Text.Mono}"
+                               Foreground="{DynamicResource Wd.Text.Tertiary}"
+                               VerticalAlignment="Center"/>
+                    <TextBlock Grid.Column="1"
+                               Text="{Binding StatusText}"
+                               Style="{StaticResource Wd.Text.Mono}"
+                               Foreground="{DynamicResource Wd.Text.Tertiary}"
+                               HorizontalAlignment="Center"
+                               VerticalAlignment="Center"/>
+                    <TextBlock Grid.Column="2"
+                               Text="wilddragon.net · 1.0.0-alpha"
+                               Style="{StaticResource Wd.Text.Mono}"
+                               Foreground="{DynamicResource Wd.Text.Tertiary}"
+                               VerticalAlignment="Center"/>
+                </Grid>
+            </Border>
+
+            <!-- Body -->
+            <Grid Margin="32,28,32,28">
+                <Grid.RowDefinitions>
+                    <RowDefinition Height="Auto"/>
+                    <RowDefinition Height="Auto"/>
+                    <RowDefinition Height="*"/>
+                </Grid.RowDefinitions>
+
+                <!-- Section header -->
+                <StackPanel Grid.Row="0" Orientation="Horizontal" VerticalAlignment="Center">
+                    <TextBlock Text="Participants"
+                               Style="{StaticResource Wd.Text.Heading}"
+                               FontSize="18"/>
+                    <Border Style="{StaticResource Wd.Pill}"
+                            Margin="12,0,0,0"
+                            VerticalAlignment="Center">
+                        <TextBlock Text="{Binding Participants.Count}"
+                                   Style="{StaticResource Wd.Text.Mono}"
+                                   FontSize="11"/>
+                    </Border>
+                </StackPanel>
+
+                <TextBlock Grid.Row="1"
+                           Text="Toggle a participant's ISO to spin up an isolated, normalized NDI output."
+                           Style="{StaticResource Wd.Text.Subtle}"
+                           Foreground="{DynamicResource Wd.Text.Tertiary}"
+                           Margin="0,6,0,18"/>
+
+                <!-- Participants card -->
+                <Border Grid.Row="2"
+                        Style="{StaticResource Wd.Card}"
+                        Padding="0">
+                    <DataGrid ItemsSource="{Binding Participants}"
+                              Margin="6,4,6,4">
+                        <DataGrid.Columns>
+                            <DataGridTemplateColumn Header="Display Name" Width="2*">
+                                <DataGridTemplateColumn.CellTemplate>
+                                    <DataTemplate>
+                                        <StackPanel Orientation="Horizontal" VerticalAlignment="Center">
+                                            <Border Style="{StaticResource Wd.Avatar}">
+                                                <TextBlock Text="{Binding DisplayName, Converter={StaticResource Initials}}"
+                                                           Foreground="{DynamicResource Wd.Accent.Cyan}"
+                                                           FontFamily="{StaticResource Wd.Font.Sans}"
+                                                           FontWeight="SemiBold"
+                                                           FontSize="11"
+                                                           HorizontalAlignment="Center"
+                                                           VerticalAlignment="Center"/>
+                                            </Border>
+                                            <TextBlock Text="{Binding DisplayName}"
+                                                       Style="{StaticResource Wd.Text.Body}"
+                                                       FontWeight="Medium"
+                                                       Margin="14,0,0,0"
+                                                       VerticalAlignment="Center"/>
+                                        </StackPanel>
+                                    </DataTemplate>
+                                </DataGridTemplateColumn.CellTemplate>
+                            </DataGridTemplateColumn>
+
+                            <DataGridTemplateColumn Header="Source" Width="*">
+                                <DataGridTemplateColumn.CellTemplate>
+                                    <DataTemplate>
+                                        <TextBlock Text="{Binding SourceMachine}"
+                                                   Style="{StaticResource Wd.Text.Mono}"
+                                                   VerticalAlignment="Center"/>
+                                    </DataTemplate>
+                                </DataGridTemplateColumn.CellTemplate>
+                            </DataGridTemplateColumn>
+
+                            <DataGridTemplateColumn Header="Output Name" Width="2*">
+                                <DataGridTemplateColumn.CellTemplate>
+                                    <DataTemplate>
+                                        <TextBox Text="{Binding CustomName, UpdateSourceTrigger=PropertyChanged}"
+                                                 Padding="10,7"
+                                                 Margin="0,0,12,0"
+                                                 VerticalAlignment="Center"/>
+                                    </DataTemplate>
+                                </DataGridTemplateColumn.CellTemplate>
+                            </DataGridTemplateColumn>
+
+                            <DataGridTemplateColumn Header="ISO" Width="130">
+                                <DataGridTemplateColumn.CellTemplate>
+                                    <DataTemplate>
+                                        <Button Command="{Binding ToggleIsoCommand}"
+                                                Margin="0,0,12,0">
+                                            <Button.Style>
+                                                <Style TargetType="Button" BasedOn="{StaticResource Wd.Button.IsoToggle}">
+                                                    <Setter Property="Content" Value="Enable"/>
+                                                    <Setter Property="Foreground" Value="{DynamicResource Wd.Text.Secondary}"/>
+                                                    <Style.Triggers>
+                                                        <DataTrigger Binding="{Binding IsEnabled}" Value="True">
+                                                            <Setter Property="Content" Value="● LIVE"/>
+                                                            <Setter Property="Background" Value="{DynamicResource Wd.Accent.CyanMuted}"/>
+                                                            <Setter Property="BorderBrush" Value="{DynamicResource Wd.Accent.Cyan}"/>
+                                                            <Setter Property="Foreground" Value="{DynamicResource Wd.Accent.Cyan}"/>
+                                                        </DataTrigger>
+                                                        <DataTrigger Binding="{Binding IsProcessing}" Value="True">
+                                                            <Setter Property="Content" Value="…"/>
+                                                            <Setter Property="IsEnabled" Value="False"/>
+                                                        </DataTrigger>
+                                                    </Style.Triggers>
+                                                </Style>
+                                            </Button.Style>
+                                        </Button>
+                                    </DataTemplate>
+                                </DataGridTemplateColumn.CellTemplate>
+                            </DataGridTemplateColumn>
+                        </DataGrid.Columns>
+                    </DataGrid>
+                </Border>
+            </Grid>
+        </DockPanel>
+
+        <!-- ════════════════════════════════════════════════════════════════
+             SETTINGS PANEL (right)
+             ════════════════════════════════════════════════════════════════ -->
+        <Border Grid.Column="2"
+                Background="{DynamicResource Wd.Surface}"
+                BorderBrush="{DynamicResource Wd.Border}"
+                BorderThickness="1,0,0,0">
             <ScrollViewer VerticalScrollBarVisibility="Auto">
-                <StackPanel>
-                    <TextBlock Text="Global Settings" FontSize="16" FontWeight="Bold" Margin="0,0,0,12"/>
+                <StackPanel Margin="24,28,24,32">
 
-                    <TextBlock Text="Target Framerate"/>
+                    <TextBlock Text="Settings"
+                               Style="{StaticResource Wd.Text.Heading}"
+                               FontSize="16"
+                               Margin="0,0,0,4"/>
+                    <TextBlock Text="Per-meeting global processing"
+                               Style="{StaticResource Wd.Text.Subtle}"
+                               Foreground="{DynamicResource Wd.Text.Tertiary}"
+                               Margin="0,0,0,22"/>
+
+                    <!-- Output Format -->
+                    <TextBlock Text="OUTPUT FORMAT" Style="{StaticResource Wd.Text.Caption}"/>
+
+                    <TextBlock Text="Target Framerate"
+                               Style="{StaticResource Wd.Text.Subtle}"
+                               Margin="0,10,0,4"/>
                     <ComboBox ItemsSource="{Binding Settings.AvailableFramerates}"
                               SelectedItem="{Binding Settings.Framerate}">
                         <ComboBox.ItemTemplate>
@@ -66,7 +361,9 @@
                         </ComboBox.ItemTemplate>
                     </ComboBox>
 
-                    <TextBlock Text="Target Resolution"/>
+                    <TextBlock Text="Target Resolution"
+                               Style="{StaticResource Wd.Text.Subtle}"
+                               Margin="0,12,0,4"/>
                     <ComboBox ItemsSource="{Binding Settings.AvailableResolutions}"
                               SelectedItem="{Binding Settings.Resolution}">
                         <ComboBox.ItemTemplate>
@@ -76,7 +373,9 @@
                         </ComboBox.ItemTemplate>
                     </ComboBox>
 
-                    <TextBlock Text="Aspect Mode"/>
+                    <TextBlock Text="Aspect Mode"
+                               Style="{StaticResource Wd.Text.Subtle}"
+                               Margin="0,12,0,4"/>
                     <ComboBox ItemsSource="{Binding Settings.AvailableAspectModes}"
                               SelectedItem="{Binding Settings.Aspect}">
                         <ComboBox.ItemTemplate>
@@ -86,7 +385,9 @@
                         </ComboBox.ItemTemplate>
                     </ComboBox>
 
-                    <TextBlock Text="Audio Mode"/>
+                    <TextBlock Text="Audio Mode"
+                               Style="{StaticResource Wd.Text.Subtle}"
+                               Margin="0,12,0,4"/>
                     <ComboBox ItemsSource="{Binding Settings.AvailableAudioModes}"
                               SelectedItem="{Binding Settings.Audio}">
                         <ComboBox.ItemTemplate>
@@ -96,64 +397,62 @@
                         </ComboBox.ItemTemplate>
                     </ComboBox>
 
-                    <Button Content="Apply" Command="{Binding Settings.ApplyCommand}" Margin="0,16,0,0"/>
+                    <!-- NDI Network -->
+                    <TextBlock Text="NDI NETWORK"
+                               Style="{StaticResource Wd.Text.Caption}"
+                               Margin="0,28,0,0"/>
+
+                    <TextBlock Text="Discovery group"
+                               Style="{StaticResource Wd.Text.Subtle}"
+                               Margin="0,10,0,4"/>
+                    <TextBox Text="{Binding Settings.DiscoveryGroups, UpdateSourceTrigger=PropertyChanged}"/>
+                    <TextBlock Text="Receive sources from this group. Empty = Public."
+                               Style="{StaticResource Wd.Text.Body}"
+                               FontSize="11"
+                               Foreground="{DynamicResource Wd.Text.Tertiary}"
+                               Margin="0,4,0,0"/>
+
+                    <TextBlock Text="Output group"
+                               Style="{StaticResource Wd.Text.Subtle}"
+                               Margin="0,12,0,4"/>
+                    <TextBox Text="{Binding Settings.OutputGroups, UpdateSourceTrigger=PropertyChanged}"/>
+                    <TextBlock Text="Broadcast TeamsISO outputs on this group. Empty = Public."
+                               Style="{StaticResource Wd.Text.Body}"
+                               FontSize="11"
+                               Foreground="{DynamicResource Wd.Text.Tertiary}"
+                               Margin="0,4,0,0"/>
+
+                    <Border Background="{DynamicResource Wd.SurfaceElevated}"
+                            BorderBrush="{DynamicResource Wd.Border}"
+                            BorderThickness="1"
+                            CornerRadius="{StaticResource Radius.M}"
+                            Padding="12,10"
+                            Margin="0,12,0,0">
+                        <TextBlock Style="{StaticResource Wd.Text.Body}"
+                                   FontSize="11"
+                                   Foreground="{DynamicResource Wd.Text.Secondary}"
+                                   TextWrapping="Wrap"
+                                   Text="Group changes apply on next launch — running pipelines aren't restarted to avoid orphaning live ISOs."/>
+                    </Border>
+
+                    <!-- Display -->
+                    <TextBlock Text="DISPLAY"
+                               Style="{StaticResource Wd.Text.Caption}"
+                               Margin="0,28,0,0"/>
+
+                    <CheckBox Content="Hide my self-preview from participants"
+                              IsChecked="{Binding Settings.HideLocalSelf}"
+                              Margin="0,10,0,0"/>
+
+                    <Button Style="{StaticResource Wd.Button.Primary}"
+                            Content="Apply Changes"
+                            Command="{Binding Settings.ApplyCommand}"
+                            HorizontalAlignment="Stretch"
+                            Margin="0,28,0,0"
+                            Padding="0,11"/>
                 </StackPanel>
             </ScrollViewer>
         </Border>
 
-        <!-- Main content: participants list -->
-        <Grid Margin="14">
-            <Grid.RowDefinitions>
-                <RowDefinition Height="Auto"/>
-                <RowDefinition Height="*"/>
-            </Grid.RowDefinitions>
-
-            <TextBlock Grid.Row="0"
-                       Text="Participants"
-                       FontSize="16" FontWeight="Bold"
-                       Margin="0,0,0,8"/>
-
-            <DataGrid Grid.Row="1"
-                      ItemsSource="{Binding Participants}"
-                      AutoGenerateColumns="False"
-                      Background="#2A2C32"
-                      Foreground="#E8E8E8"
-                      RowBackground="#2A2C32"
-                      AlternatingRowBackground="#2E3037"
-                      BorderBrush="#5A5C63"
-                      GridLinesVisibility="Horizontal"
-                      HeadersVisibility="Column"
-                      CanUserAddRows="False" CanUserDeleteRows="False"
-                      RowHeight="34">
-                <DataGrid.Columns>
-                    <DataGridTextColumn Header="Display Name" Binding="{Binding DisplayName}" Width="2*" IsReadOnly="True"/>
-                    <DataGridTextColumn Header="Source" Binding="{Binding SourceMachine}" Width="*" IsReadOnly="True"/>
-                    <DataGridTextColumn Header="ISO Output Name" Binding="{Binding CustomName, UpdateSourceTrigger=PropertyChanged}" Width="2*"/>
-                    <DataGridTemplateColumn Header="ISO" Width="100">
-                        <DataGridTemplateColumn.CellTemplate>
-                            <DataTemplate>
-                                <Button Content="{Binding IsEnabled, StringFormat={}{0}}" Command="{Binding ToggleIsoCommand}">
-                                    <Button.Style>
-                                        <Style TargetType="Button">
-                                            <Setter Property="Content" Value="Enable"/>
-                                            <Style.Triggers>
-                                                <DataTrigger Binding="{Binding IsEnabled}" Value="True">
-                                                    <Setter Property="Content" Value="Disable"/>
-                                                    <Setter Property="Background" Value="#3D6F45"/>
-                                                </DataTrigger>
-                                                <DataTrigger Binding="{Binding IsProcessing}" Value="True">
-                                                    <Setter Property="Content" Value="…"/>
-                                                </DataTrigger>
-                                            </Style.Triggers>
-                                        </Style>
-                                    </Button.Style>
-                                </Button>
-                            </DataTemplate>
-                        </DataGridTemplateColumn.CellTemplate>
-                    </DataGridTemplateColumn>
-                </DataGrid.Columns>
-            </DataGrid>
-        </Grid>
-
-    </DockPanel>
+    </Grid>
 </Window>

src/TeamsISO.App/Themes/WildDragonTheme.xaml

@@ -0,0 +1,544 @@
+<ResourceDictionary
+    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:sys="clr-namespace:System;assembly=mscorlib">
+
+    <!--
+        TeamsISO design system — Wild Dragon brand × Microsoft Teams layout.
+
+        Brand reference: wilddragon.net
+            Primary canvas:   #0a0a0a
+            Accent cyan:      #97EDF0
+            Secondary blue:   #9AE0FD
+            Coral (errors):   #FB819C
+            Earth (warnings): #423825
+            Fonts:            Inter (primary), JetBrains Mono
+
+        Layout reference: Microsoft Teams desktop
+            - Left rail (72px) for app icon + primary nav
+            - Top header inside content area
+            - Card-based main panel with rounded corners (8-12px)
+            - Subtle elevation through tone, not heavy shadows
+            - Avatar circles for participants
+
+        Inter is not a Windows system font; we list it first and fall back to
+        Segoe UI Variable Display (Windows 11) and Segoe UI. JetBrains Mono
+        falls back to Cascadia Mono.
+    -->
+
+    <!-- ════ Spacing (8px grid) ════ -->
+    <sys:Double x:Key="Space.XS">4</sys:Double>
+    <sys:Double x:Key="Space.S">8</sys:Double>
+    <sys:Double x:Key="Space.M">12</sys:Double>
+    <sys:Double x:Key="Space.L">16</sys:Double>
+    <sys:Double x:Key="Space.XL">24</sys:Double>
+    <sys:Double x:Key="Space.XXL">32</sys:Double>
+
+    <!-- ════ Radii (Teams uses 6/8/12) ════ -->
+    <CornerRadius x:Key="Radius.S">6</CornerRadius>
+    <CornerRadius x:Key="Radius.M">8</CornerRadius>
+    <CornerRadius x:Key="Radius.L">12</CornerRadius>
+    <CornerRadius x:Key="Radius.XL">16</CornerRadius>
+
+    <!-- ════ Wild Dragon palette (dark) ════ -->
+    <SolidColorBrush x:Key="Wd.Canvas"           Color="#0A0A0A"/>
+    <SolidColorBrush x:Key="Wd.Rail"             Color="#080808"/>
+    <SolidColorBrush x:Key="Wd.Surface"          Color="#141414"/>
+    <SolidColorBrush x:Key="Wd.SurfaceElevated"  Color="#1C1C1C"/>
+    <SolidColorBrush x:Key="Wd.SurfaceHover"     Color="#242424"/>
+    <SolidColorBrush x:Key="Wd.SurfaceActive"    Color="#2D2D2D"/>
+    <SolidColorBrush x:Key="Wd.Border"           Color="#262626"/>
+    <SolidColorBrush x:Key="Wd.BorderStrong"     Color="#383838"/>
+
+    <SolidColorBrush x:Key="Wd.Text.Primary"     Color="#F5F5F5"/>
+    <SolidColorBrush x:Key="Wd.Text.Secondary"   Color="#A3A3A3"/>
+    <SolidColorBrush x:Key="Wd.Text.Tertiary"    Color="#6B6B6B"/>
+    <SolidColorBrush x:Key="Wd.Text.Disabled"    Color="#404040"/>
+
+    <!-- Accents from wilddragon.net -->
+    <SolidColorBrush x:Key="Wd.Accent.Cyan"      Color="#97EDF0"/>
+    <SolidColorBrush x:Key="Wd.Accent.CyanHover" Color="#B5F2F4"/>
+    <SolidColorBrush x:Key="Wd.Accent.CyanMuted" Color="#1B3537"/>
+    <SolidColorBrush x:Key="Wd.Accent.Blue"      Color="#9AE0FD"/>
+    <SolidColorBrush x:Key="Wd.Accent.Coral"     Color="#FB819C"/>
+    <SolidColorBrush x:Key="Wd.Accent.CoralBg"   Color="#3A1922"/>
+
+    <SolidColorBrush x:Key="Wd.Status.Live"      Color="#4ADE80"/>
+    <SolidColorBrush x:Key="Wd.Status.LiveBg"    Color="#13261A"/>
+    <SolidColorBrush x:Key="Wd.Status.Warn"      Color="#FBBF24"/>
+    <SolidColorBrush x:Key="Wd.Status.Error"     Color="#FB819C"/>
+
+    <!-- ════ Typography ════ -->
+    <FontFamily x:Key="Wd.Font.Sans">Inter, Segoe UI Variable Display, Segoe UI, sans-serif</FontFamily>
+    <FontFamily x:Key="Wd.Font.Mono">JetBrains Mono, Cascadia Mono, Consolas, monospace</FontFamily>
+
+    <Style x:Key="Wd.Text.Title" TargetType="TextBlock">
+        <Setter Property="FontFamily" Value="{StaticResource Wd.Font.Sans}"/>
+        <Setter Property="FontSize" Value="20"/>
+        <Setter Property="FontWeight" Value="SemiBold"/>
+        <Setter Property="Foreground" Value="{StaticResource Wd.Text.Primary}"/>
+    </Style>
+
+    <Style x:Key="Wd.Text.Heading" TargetType="TextBlock">
+        <Setter Property="FontFamily" Value="{StaticResource Wd.Font.Sans}"/>
+        <Setter Property="FontSize" Value="14"/>
+        <Setter Property="FontWeight" Value="SemiBold"/>
+        <Setter Property="Foreground" Value="{StaticResource Wd.Text.Primary}"/>
+    </Style>
+
+    <Style x:Key="Wd.Text.Body" TargetType="TextBlock">
+        <Setter Property="FontFamily" Value="{StaticResource Wd.Font.Sans}"/>
+        <Setter Property="FontSize" Value="13"/>
+        <Setter Property="Foreground" Value="{StaticResource Wd.Text.Primary}"/>
+    </Style>
+
+    <Style x:Key="Wd.Text.Subtle" TargetType="TextBlock" BasedOn="{StaticResource Wd.Text.Body}">
+        <Setter Property="Foreground" Value="{StaticResource Wd.Text.Secondary}"/>
+    </Style>
+
+    <Style x:Key="Wd.Text.Caption" TargetType="TextBlock">
+        <Setter Property="FontFamily" Value="{StaticResource Wd.Font.Sans}"/>
+        <Setter Property="FontSize" Value="11"/>
+        <Setter Property="FontWeight" Value="Medium"/>
+        <Setter Property="Foreground" Value="{StaticResource Wd.Text.Tertiary}"/>
+        <Setter Property="Typography.Capitals" Value="AllSmallCaps"/>
+    </Style>
+
+    <Style x:Key="Wd.Text.Mono" TargetType="TextBlock">
+        <Setter Property="FontFamily" Value="{StaticResource Wd.Font.Mono}"/>
+        <Setter Property="FontSize" Value="12"/>
+        <Setter Property="Foreground" Value="{StaticResource Wd.Text.Secondary}"/>
+    </Style>
+
+    <Style TargetType="TextBlock" BasedOn="{StaticResource Wd.Text.Body}"/>
+
+    <!-- ════ Buttons ════ -->
+    <!-- Ghost: bordered, transparent fill -->
+    <Style x:Key="Wd.Button.Ghost" TargetType="Button">
+        <Setter Property="FontFamily" Value="{StaticResource Wd.Font.Sans}"/>
+        <Setter Property="FontSize" Value="13"/>
+        <Setter Property="FontWeight" Value="Medium"/>
+        <Setter Property="Foreground" Value="{StaticResource Wd.Text.Primary}"/>
+        <Setter Property="Background" Value="Transparent"/>
+        <Setter Property="BorderBrush" Value="{StaticResource Wd.BorderStrong}"/>
+        <Setter Property="BorderThickness" Value="1"/>
+        <Setter Property="Padding" Value="14,8"/>
+        <Setter Property="Cursor" Value="Hand"/>
+        <Setter Property="HorizontalContentAlignment" Value="Center"/>
+        <Setter Property="VerticalContentAlignment" Value="Center"/>
+        <Setter Property="FocusVisualStyle" Value="{x:Null}"/>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="Button">
+                    <Border x:Name="Bd"
+                            Background="{TemplateBinding Background}"
+                            BorderBrush="{TemplateBinding BorderBrush}"
+                            BorderThickness="{TemplateBinding BorderThickness}"
+                            CornerRadius="{StaticResource Radius.M}"
+                            SnapsToDevicePixels="True">
+                        <ContentPresenter HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
+                                          VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
+                                          Margin="{TemplateBinding Padding}"/>
+                    </Border>
+                    <ControlTemplate.Triggers>
+                        <Trigger Property="IsMouseOver" Value="True">
+                            <Setter TargetName="Bd" Property="Background" Value="{StaticResource Wd.SurfaceHover}"/>
+                        </Trigger>
+                        <Trigger Property="IsPressed" Value="True">
+                            <Setter TargetName="Bd" Property="Background" Value="{StaticResource Wd.SurfaceActive}"/>
+                        </Trigger>
+                        <Trigger Property="IsEnabled" Value="False">
+                            <Setter Property="Foreground" Value="{StaticResource Wd.Text.Disabled}"/>
+                            <Setter TargetName="Bd" Property="Opacity" Value="0.6"/>
+                        </Trigger>
+                    </ControlTemplate.Triggers>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
+    <!-- Primary: cyan-on-black for the brand action -->
+    <Style x:Key="Wd.Button.Primary" TargetType="Button" BasedOn="{StaticResource Wd.Button.Ghost}">
+        <Setter Property="Background" Value="{StaticResource Wd.Accent.Cyan}"/>
+        <Setter Property="BorderBrush" Value="{StaticResource Wd.Accent.Cyan}"/>
+        <Setter Property="Foreground" Value="#0A0A0A"/>
+        <Setter Property="FontWeight" Value="SemiBold"/>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="Button">
+                    <Border x:Name="Bd"
+                            Background="{TemplateBinding Background}"
+                            BorderBrush="{TemplateBinding BorderBrush}"
+                            BorderThickness="{TemplateBinding BorderThickness}"
+                            CornerRadius="{StaticResource Radius.M}">
+                        <ContentPresenter HorizontalAlignment="Center"
+                                          VerticalAlignment="Center"
+                                          Margin="{TemplateBinding Padding}"/>
+                    </Border>
+                    <ControlTemplate.Triggers>
+                        <Trigger Property="IsMouseOver" Value="True">
+                            <Setter TargetName="Bd" Property="Background" Value="{StaticResource Wd.Accent.CyanHover}"/>
+                            <Setter TargetName="Bd" Property="BorderBrush" Value="{StaticResource Wd.Accent.CyanHover}"/>
+                        </Trigger>
+                    </ControlTemplate.Triggers>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
+    <!-- Rail-icon button: square 48x48, used on the Teams-style left rail -->
+    <Style x:Key="Wd.Button.RailIcon" TargetType="Button">
+        <Setter Property="Background" Value="Transparent"/>
+        <Setter Property="BorderThickness" Value="0"/>
+        <Setter Property="Foreground" Value="{StaticResource Wd.Text.Secondary}"/>
+        <Setter Property="Width" Value="48"/>
+        <Setter Property="Height" Value="48"/>
+        <Setter Property="Margin" Value="0,4"/>
+        <Setter Property="Cursor" Value="Hand"/>
+        <Setter Property="FocusVisualStyle" Value="{x:Null}"/>
+        <Setter Property="HorizontalContentAlignment" Value="Center"/>
+        <Setter Property="VerticalContentAlignment" Value="Center"/>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="Button">
+                    <Border x:Name="Bd"
+                            Background="{TemplateBinding Background}"
+                            CornerRadius="{StaticResource Radius.M}">
+                        <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
+                    </Border>
+                    <ControlTemplate.Triggers>
+                        <Trigger Property="IsMouseOver" Value="True">
+                            <Setter TargetName="Bd" Property="Background" Value="{StaticResource Wd.SurfaceHover}"/>
+                            <Setter Property="Foreground" Value="{StaticResource Wd.Text.Primary}"/>
+                        </Trigger>
+                    </ControlTemplate.Triggers>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
+    <!-- ISO toggle: pill, status-coded -->
+    <Style x:Key="Wd.Button.IsoToggle" TargetType="Button">
+        <Setter Property="FontFamily" Value="{StaticResource Wd.Font.Sans}"/>
+        <Setter Property="FontSize" Value="11"/>
+        <Setter Property="FontWeight" Value="SemiBold"/>
+        <Setter Property="Foreground" Value="{StaticResource Wd.Text.Primary}"/>
+        <Setter Property="Background" Value="{StaticResource Wd.SurfaceHover}"/>
+        <Setter Property="BorderBrush" Value="{StaticResource Wd.BorderStrong}"/>
+        <Setter Property="BorderThickness" Value="1"/>
+        <Setter Property="Padding" Value="14,6"/>
+        <Setter Property="Cursor" Value="Hand"/>
+        <Setter Property="HorizontalContentAlignment" Value="Center"/>
+        <Setter Property="MinWidth" Value="84"/>
+        <Setter Property="FocusVisualStyle" Value="{x:Null}"/>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="Button">
+                    <Border x:Name="Bd"
+                            Background="{TemplateBinding Background}"
+                            BorderBrush="{TemplateBinding BorderBrush}"
+                            BorderThickness="{TemplateBinding BorderThickness}"
+                            CornerRadius="999">
+                        <ContentPresenter HorizontalAlignment="Center"
+                                          VerticalAlignment="Center"
+                                          Margin="{TemplateBinding Padding}"/>
+                    </Border>
+                    <ControlTemplate.Triggers>
+                        <Trigger Property="IsMouseOver" Value="True">
+                            <Setter TargetName="Bd" Property="Background" Value="{StaticResource Wd.SurfaceActive}"/>
+                        </Trigger>
+                    </ControlTemplate.Triggers>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
+    <!-- ════ TextBox ════ -->
+    <Style x:Key="Wd.TextBox.Default" TargetType="TextBox">
+        <Setter Property="FontFamily" Value="{StaticResource Wd.Font.Sans}"/>
+        <Setter Property="FontSize" Value="13"/>
+        <Setter Property="Foreground" Value="{StaticResource Wd.Text.Primary}"/>
+        <Setter Property="Background" Value="{StaticResource Wd.Surface}"/>
+        <Setter Property="CaretBrush" Value="{StaticResource Wd.Accent.Cyan}"/>
+        <Setter Property="SelectionBrush" Value="{StaticResource Wd.Accent.CyanMuted}"/>
+        <Setter Property="BorderBrush" Value="{StaticResource Wd.Border}"/>
+        <Setter Property="BorderThickness" Value="1"/>
+        <Setter Property="Padding" Value="12,9"/>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="TextBox">
+                    <Border x:Name="Bd"
+                            Background="{TemplateBinding Background}"
+                            BorderBrush="{TemplateBinding BorderBrush}"
+                            BorderThickness="{TemplateBinding BorderThickness}"
+                            CornerRadius="{StaticResource Radius.M}">
+                        <ScrollViewer x:Name="PART_ContentHost"
+                                      Margin="{TemplateBinding Padding}"
+                                      VerticalAlignment="Center"
+                                      Focusable="False"/>
+                    </Border>
+                    <ControlTemplate.Triggers>
+                        <Trigger Property="IsKeyboardFocused" Value="True">
+                            <Setter TargetName="Bd" Property="BorderBrush" Value="{StaticResource Wd.Accent.Cyan}"/>
+                        </Trigger>
+                        <Trigger Property="IsMouseOver" Value="True">
+                            <Setter TargetName="Bd" Property="BorderBrush" Value="{StaticResource Wd.BorderStrong}"/>
+                        </Trigger>
+                    </ControlTemplate.Triggers>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+    <Style TargetType="TextBox" BasedOn="{StaticResource Wd.TextBox.Default}"/>
+
+    <!-- ════ ComboBox ════ -->
+    <Style x:Key="Wd.ComboToggle" TargetType="ToggleButton">
+        <Setter Property="OverridesDefaultStyle" Value="True"/>
+        <Setter Property="IsTabStop" Value="False"/>
+        <Setter Property="Focusable" Value="False"/>
+        <Setter Property="ClickMode" Value="Press"/>
+        <Setter Property="Background" Value="Transparent"/>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="ToggleButton">
+                    <Path HorizontalAlignment="Right"
+                          VerticalAlignment="Center"
+                          Margin="0,0,14,0"
+                          Data="M 0,0 L 4,4 L 8,0 Z"
+                          Fill="{StaticResource Wd.Text.Secondary}"/>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
+    <Style TargetType="ComboBox">
+        <Setter Property="FontFamily" Value="{StaticResource Wd.Font.Sans}"/>
+        <Setter Property="FontSize" Value="13"/>
+        <Setter Property="Foreground" Value="{StaticResource Wd.Text.Primary}"/>
+        <Setter Property="Background" Value="{StaticResource Wd.Surface}"/>
+        <Setter Property="BorderBrush" Value="{StaticResource Wd.Border}"/>
+        <Setter Property="BorderThickness" Value="1"/>
+        <Setter Property="Padding" Value="12,9"/>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="ComboBox">
+                    <Grid>
+                        <Border x:Name="Bd"
+                                Background="{TemplateBinding Background}"
+                                BorderBrush="{TemplateBinding BorderBrush}"
+                                BorderThickness="{TemplateBinding BorderThickness}"
+                                CornerRadius="{StaticResource Radius.M}"/>
+                        <ToggleButton Style="{StaticResource Wd.ComboToggle}"
+                                      IsChecked="{Binding IsDropDownOpen,
+                                          RelativeSource={RelativeSource TemplatedParent}, Mode=TwoWay}"/>
+                        <ContentPresenter Margin="{TemplateBinding Padding}"
+                                          IsHitTestVisible="False"
+                                          VerticalAlignment="Center"
+                                          Content="{TemplateBinding SelectionBoxItem}"
+                                          ContentTemplate="{TemplateBinding SelectionBoxItemTemplate}"/>
+                        <Popup IsOpen="{TemplateBinding IsDropDownOpen}"
+                               Placement="Bottom"
+                               AllowsTransparency="True"
+                               Focusable="False"
+                               PopupAnimation="None">
+                            <Border Background="{StaticResource Wd.SurfaceElevated}"
+                                    BorderBrush="{StaticResource Wd.BorderStrong}"
+                                    BorderThickness="1"
+                                    CornerRadius="{StaticResource Radius.M}"
+                                    MinWidth="{TemplateBinding ActualWidth}"
+                                    MaxHeight="280"
+                                    Margin="0,4,0,0">
+                                <ScrollViewer><ItemsPresenter/></ScrollViewer>
+                            </Border>
+                        </Popup>
+                    </Grid>
+                    <ControlTemplate.Triggers>
+                        <Trigger Property="IsMouseOver" Value="True">
+                            <Setter TargetName="Bd" Property="BorderBrush" Value="{StaticResource Wd.BorderStrong}"/>
+                        </Trigger>
+                        <Trigger Property="IsKeyboardFocusWithin" Value="True">
+                            <Setter TargetName="Bd" Property="BorderBrush" Value="{StaticResource Wd.Accent.Cyan}"/>
+                        </Trigger>
+                    </ControlTemplate.Triggers>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
+    <Style TargetType="ComboBoxItem">
+        <Setter Property="Foreground" Value="{StaticResource Wd.Text.Primary}"/>
+        <Setter Property="Padding" Value="12,9"/>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="ComboBoxItem">
+                    <Border x:Name="Bd"
+                            Background="Transparent"
+                            CornerRadius="{StaticResource Radius.S}"
+                            Margin="4,2"
+                            Padding="{TemplateBinding Padding}">
+                        <ContentPresenter/>
+                    </Border>
+                    <ControlTemplate.Triggers>
+                        <Trigger Property="IsMouseOver" Value="True">
+                            <Setter TargetName="Bd" Property="Background" Value="{StaticResource Wd.SurfaceHover}"/>
+                        </Trigger>
+                        <Trigger Property="IsHighlighted" Value="True">
+                            <Setter TargetName="Bd" Property="Background" Value="{StaticResource Wd.SurfaceHover}"/>
+                        </Trigger>
+                    </ControlTemplate.Triggers>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
+    <!-- ════ CheckBox ════ -->
+    <Style TargetType="CheckBox">
+        <Setter Property="FontFamily" Value="{StaticResource Wd.Font.Sans}"/>
+        <Setter Property="FontSize" Value="13"/>
+        <Setter Property="Foreground" Value="{StaticResource Wd.Text.Primary}"/>
+        <Setter Property="Cursor" Value="Hand"/>
+        <Setter Property="Padding" Value="10,0,0,0"/>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="CheckBox">
+                    <StackPanel Orientation="Horizontal">
+                        <Border x:Name="Box"
+                                Width="18" Height="18"
+                                BorderBrush="{StaticResource Wd.BorderStrong}"
+                                BorderThickness="1"
+                                Background="{StaticResource Wd.Surface}"
+                                CornerRadius="4"
+                                VerticalAlignment="Center">
+                            <Path x:Name="Tick"
+                                  Data="M 4,9 L 7.5,12.5 L 14,5"
+                                  Stroke="#0A0A0A" StrokeThickness="2"
+                                  StrokeStartLineCap="Round"
+                                  StrokeEndLineCap="Round"
+                                  Visibility="Collapsed"/>
+                        </Border>
+                        <ContentPresenter Margin="{TemplateBinding Padding}"
+                                          VerticalAlignment="Center"/>
+                    </StackPanel>
+                    <ControlTemplate.Triggers>
+                        <Trigger Property="IsChecked" Value="True">
+                            <Setter TargetName="Box" Property="Background" Value="{StaticResource Wd.Accent.Cyan}"/>
+                            <Setter TargetName="Box" Property="BorderBrush" Value="{StaticResource Wd.Accent.Cyan}"/>
+                            <Setter TargetName="Tick" Property="Visibility" Value="Visible"/>
+                        </Trigger>
+                        <Trigger Property="IsMouseOver" Value="True">
+                            <Setter TargetName="Box" Property="BorderBrush" Value="{StaticResource Wd.Accent.Cyan}"/>
+                        </Trigger>
+                    </ControlTemplate.Triggers>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
+    <!-- ════ Card ════ -->
+    <Style x:Key="Wd.Card" TargetType="Border">
+        <Setter Property="Background" Value="{StaticResource Wd.Surface}"/>
+        <Setter Property="BorderBrush" Value="{StaticResource Wd.Border}"/>
+        <Setter Property="BorderThickness" Value="1"/>
+        <Setter Property="CornerRadius" Value="{StaticResource Radius.L}"/>
+        <Setter Property="Padding" Value="16"/>
+    </Style>
+
+    <!-- ════ DataGrid (re-skinned, Teams-style) ════ -->
+    <Style TargetType="DataGrid">
+        <Setter Property="Background" Value="Transparent"/>
+        <Setter Property="Foreground" Value="{StaticResource Wd.Text.Primary}"/>
+        <Setter Property="BorderThickness" Value="0"/>
+        <Setter Property="GridLinesVisibility" Value="None"/>
+        <Setter Property="HeadersVisibility" Value="Column"/>
+        <Setter Property="RowHeight" Value="56"/>
+        <Setter Property="RowBackground" Value="Transparent"/>
+        <Setter Property="AlternatingRowBackground" Value="Transparent"/>
+        <Setter Property="HorizontalScrollBarVisibility" Value="Auto"/>
+        <Setter Property="VerticalScrollBarVisibility" Value="Auto"/>
+        <Setter Property="CanUserAddRows" Value="False"/>
+        <Setter Property="CanUserDeleteRows" Value="False"/>
+        <Setter Property="CanUserResizeRows" Value="False"/>
+        <Setter Property="SelectionMode" Value="Single"/>
+        <Setter Property="SelectionUnit" Value="FullRow"/>
+        <Setter Property="AutoGenerateColumns" Value="False"/>
+    </Style>
+
+    <Style TargetType="DataGridColumnHeader">
+        <Setter Property="FontFamily" Value="{StaticResource Wd.Font.Sans}"/>
+        <Setter Property="FontSize" Value="11"/>
+        <Setter Property="FontWeight" Value="Medium"/>
+        <Setter Property="Foreground" Value="{StaticResource Wd.Text.Tertiary}"/>
+        <Setter Property="Background" Value="Transparent"/>
+        <Setter Property="BorderBrush" Value="{StaticResource Wd.Border}"/>
+        <Setter Property="BorderThickness" Value="0,0,0,1"/>
+        <Setter Property="Padding" Value="14,12"/>
+        <Setter Property="HorizontalContentAlignment" Value="Left"/>
+        <Setter Property="Typography.Capitals" Value="AllSmallCaps"/>
+    </Style>
+
+    <Style TargetType="DataGridRow">
+        <Setter Property="Background" Value="Transparent"/>
+        <Setter Property="BorderBrush" Value="{StaticResource Wd.Border}"/>
+        <Setter Property="BorderThickness" Value="0,0,0,1"/>
+        <Style.Triggers>
+            <Trigger Property="IsMouseOver" Value="True">
+                <Setter Property="Background" Value="{StaticResource Wd.SurfaceHover}"/>
+            </Trigger>
+            <Trigger Property="IsSelected" Value="True">
+                <Setter Property="Background" Value="{StaticResource Wd.SurfaceElevated}"/>
+            </Trigger>
+        </Style.Triggers>
+    </Style>
+
+    <Style TargetType="DataGridCell">
+        <Setter Property="Background" Value="Transparent"/>
+        <Setter Property="BorderThickness" Value="0"/>
+        <Setter Property="Padding" Value="14,0"/>
+        <Setter Property="VerticalAlignment" Value="Center"/>
+        <Setter Property="Foreground" Value="{StaticResource Wd.Text.Primary}"/>
+        <Setter Property="FocusVisualStyle" Value="{x:Null}"/>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="DataGridCell">
+                    <Border Background="{TemplateBinding Background}"
+                            Padding="{TemplateBinding Padding}">
+                        <ContentPresenter VerticalAlignment="Center"/>
+                    </Border>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
+    <!-- ════ ScrollBar (slim) ════ -->
+    <Style TargetType="ScrollBar">
+        <Setter Property="Width" Value="10"/>
+        <Setter Property="MinWidth" Value="10"/>
+        <Setter Property="Background" Value="Transparent"/>
+        <Style.Triggers>
+            <Trigger Property="Orientation" Value="Horizontal">
+                <Setter Property="Height" Value="10"/>
+                <Setter Property="MinHeight" Value="10"/>
+                <Setter Property="Width" Value="Auto"/>
+            </Trigger>
+        </Style.Triggers>
+    </Style>
+
+    <!-- ════ Avatar (28px circle with initials) ════ -->
+    <Style x:Key="Wd.Avatar" TargetType="Border">
+        <Setter Property="Width" Value="32"/>
+        <Setter Property="Height" Value="32"/>
+        <Setter Property="CornerRadius" Value="16"/>
+        <Setter Property="Background" Value="{StaticResource Wd.Accent.CyanMuted}"/>
+        <Setter Property="BorderBrush" Value="{StaticResource Wd.Accent.Cyan}"/>
+        <Setter Property="BorderThickness" Value="1"/>
+    </Style>
+
+    <!-- ════ Status pill ════ -->
+    <Style x:Key="Wd.Pill" TargetType="Border">
+        <Setter Property="Background" Value="{StaticResource Wd.SurfaceElevated}"/>
+        <Setter Property="CornerRadius" Value="999"/>
+        <Setter Property="Padding" Value="10,4"/>
+        <Setter Property="HorizontalAlignment" Value="Left"/>
+    </Style>
+
+</ResourceDictionary>

src/TeamsISO.App/ViewModels/GlobalSettingsViewModel.cs

@@ -4,7 +4,8 @@ using TeamsISO.Engine.Domain;
 namespace TeamsISO.App.ViewModels;
 
 /// <summary>
-/// Bindings for the global settings panel: framerate, resolution, aspect, audio.
+/// Bindings for the global settings panel: framerate, resolution, aspect, audio,
+/// NDI groups (discovery + output), and the participant-list hide-Local toggle.
 /// </summary>
 public sealed class GlobalSettingsViewModel : ObservableObject
 {
@@ -13,6 +14,9 @@ public sealed class GlobalSettingsViewModel : ObservableObject
     private TargetResolution _resolution;
     private AspectMode _aspect;
     private AudioMode _audio;
+    private string _discoveryGroups;
+    private string _outputGroups;
+    private bool _hideLocalSelf = true;
 
     public GlobalSettingsViewModel(IIsoController controller)
     {
@@ -22,6 +26,11 @@ public sealed class GlobalSettingsViewModel : ObservableObject
         _resolution = current.Resolution;
         _aspect = current.Aspect;
         _audio = current.Audio;
+
+        var groups = controller.GroupSettings;
+        _discoveryGroups = groups.DiscoveryGroups ?? string.Empty;
+        _outputGroups = groups.OutputGroups ?? string.Empty;
+
         ApplyCommand = new AsyncRelayCommand(ApplyAsync);
     }
 
@@ -35,11 +44,29 @@ public sealed class GlobalSettingsViewModel : ObservableObject
     public AspectMode Aspect { get => _aspect; set => SetField(ref _aspect, value); }
     public AudioMode Audio { get => _audio; set => SetField(ref _audio, value); }
 
+    /// <summary>NDI discovery group(s) — comma-separated. Empty = default (Public).</summary>
+    public string DiscoveryGroups { get => _discoveryGroups; set => SetField(ref _discoveryGroups, value); }
+
+    /// <summary>NDI output group(s) — comma-separated. Empty = default (Public).</summary>
+    public string OutputGroups { get => _outputGroups; set => SetField(ref _outputGroups, value); }
+
+    /// <summary>
+    /// Hide the user's own self-preview ("(Local)") from the participants list.
+    /// On by default — operators rarely want to ISO-route their own preview.
+    /// Read by <see cref="MainViewModel"/> when filtering the list it presents.
+    /// </summary>
+    public bool HideLocalSelf { get => _hideLocalSelf; set => SetField(ref _hideLocalSelf, value); }
+
     public AsyncRelayCommand ApplyCommand { get; }
 
-    private Task ApplyAsync()
+    private async Task ApplyAsync()
     {
         var settings = new FrameProcessingSettings(_framerate, _resolution, _aspect, _audio);
-        return _controller.SetGlobalSettingsAsync(settings, CancellationToken.None);
+        await _controller.SetGlobalSettingsAsync(settings, CancellationToken.None);
+
+        var groups = new NdiGroupSettings(
+            DiscoveryGroups: string.IsNullOrWhiteSpace(_discoveryGroups) ? null : _discoveryGroups.Trim(),
+            OutputGroups: string.IsNullOrWhiteSpace(_outputGroups) ? null : _outputGroups.Trim());
+        await _controller.SetGroupSettingsAsync(groups, CancellationToken.None);
     }
 }

src/TeamsISO.App/ViewModels/MainViewModel.cs

@@ -61,8 +61,14 @@ public sealed class MainViewModel : ObservableObject, IDisposable
     private void OnParticipantsChanged(IReadOnlyList<Participant> incoming)
     {
         var seenIds = new HashSet<Guid>();
+        var hideLocal = Settings.HideLocalSelf;
         foreach (var p in incoming)
         {
+            // The new Teams client emits a "(Local)" pseudo-participant for the user's
+            // own preview — operators rarely want it as a routable ISO. Suppress when
+            // HideLocalSelf is on (default).
+            if (hideLocal && IsLocalSelf(p)) continue;
+
             seenIds.Add(p.Id);
             if (_byId.TryGetValue(p.Id, out var vm))
             {
@@ -76,7 +82,7 @@ public sealed class MainViewModel : ObservableObject, IDisposable
             }
         }
 
-        // Remove participants no longer present
+        // Remove participants no longer present (or now hidden by the filter).
         for (var i = Participants.Count - 1; i >= 0; i--)
         {
             var vm = Participants[i];
@@ -88,6 +94,9 @@ public sealed class MainViewModel : ObservableObject, IDisposable
         }
     }
 
+    private static bool IsLocalSelf(Participant p) =>
+        string.Equals(p.DisplayName, "(Local)", StringComparison.Ordinal);
+
     public void Dispose()
     {
         _participantsSub.Dispose();

src/TeamsISO.Engine.NdiInterop/NdiInteropPInvoke.cs

@@ -37,12 +37,48 @@ public sealed class NdiInteropPInvoke : INdiInterop, IDisposable
 
     // ---- Discovery ----
 
-    public NdiFindHandle CreateFinder()
+    public NdiFindHandle CreateFinder(string? groups = null)
     {
-        var native = NdiNative.FindCreateV2(IntPtr.Zero);
-        if (native == IntPtr.Zero)
-            throw new InvalidOperationException("NDIlib_find_create_v2 returned null.");
-        return new NdiPInvokeFindHandle(native);
+        // Empty/whitespace -> default (Public). Otherwise allocate a UTF-8 buffer
+        // for the comma-separated group list and pin a settings struct around it.
+        var trimmed = string.IsNullOrWhiteSpace(groups) ? null : groups!.Trim();
+        if (trimmed is null)
+        {
+            var nativeDefault = NdiNative.FindCreateV2(IntPtr.Zero);
+            if (nativeDefault == IntPtr.Zero)
+                throw new InvalidOperationException("NDIlib_find_create_v2 returned null.");
+            return new NdiPInvokeFindHandle(nativeDefault);
+        }
+
+        var groupsUtf8 = Marshal.StringToHGlobalAnsi(trimmed);
+        try
+        {
+            var settings = new NdiNative.FindCreateSettings
+            {
+                show_local_sources = true,
+                p_groups = groupsUtf8,
+                p_extra_ips = IntPtr.Zero,
+            };
+            var settingsPtr = Marshal.AllocHGlobal(Marshal.SizeOf<NdiNative.FindCreateSettings>());
+            try
+            {
+                Marshal.StructureToPtr(settings, settingsPtr, false);
+                var native = NdiNative.FindCreateV2(settingsPtr);
+                if (native == IntPtr.Zero)
+                    throw new InvalidOperationException(
+                        $"NDIlib_find_create_v2 returned null for groups='{trimmed}'.");
+                _logger.LogInformation("NDI finder created with groups: {Groups}", trimmed);
+                return new NdiPInvokeFindHandle(native);
+            }
+            finally
+            {
+                Marshal.FreeHGlobal(settingsPtr);
+            }
+        }
+        finally
+        {
+            Marshal.FreeHGlobal(groupsUtf8);
+        }
     }
 
     public IReadOnlyList<string> GetCurrentSources(NdiFindHandle finder)
@@ -150,26 +186,34 @@ public sealed class NdiInteropPInvoke : INdiInterop, IDisposable
 
     // ---- Send ----
 
-    public NdiSenderHandle CreateSender(string outputName)
+    public NdiSenderHandle CreateSender(string outputName, string? groups = null)
     {
+        var trimmedGroups = string.IsNullOrWhiteSpace(groups) ? null : groups!.Trim();
         var nameUtf8 = Marshal.StringToHGlobalAnsi(outputName);
+        var groupsUtf8 = trimmedGroups is null
+            ? IntPtr.Zero
+            : Marshal.StringToHGlobalAnsi(trimmedGroups);
         try
         {
             var settings = new NdiNative.SendCreateSettings
             {
                 p_ndi_name = nameUtf8,
-                p_groups = IntPtr.Zero,
+                p_groups = groupsUtf8,
                 clock_video = true,
                 clock_audio = false
             };
             var native = NdiNative.SendCreate(ref settings);
             if (native == IntPtr.Zero)
-                throw new InvalidOperationException($"NDIlib_send_create returned null for output '{outputName}'.");
+                throw new InvalidOperationException(
+                    $"NDIlib_send_create returned null for output '{outputName}' on groups '{trimmedGroups ?? "<default>"}'.");
+            if (trimmedGroups is not null)
+                _logger.LogInformation("NDI sender '{Output}' created on groups: {Groups}", outputName, trimmedGroups);
             return new NdiPInvokeSenderHandle(native, outputName);
         }
         finally
         {
             Marshal.FreeHGlobal(nameUtf8);
+            if (groupsUtf8 != IntPtr.Zero) Marshal.FreeHGlobal(groupsUtf8);
         }
     }
 

src/TeamsISO.Engine.NdiInterop/NdiNative.cs

@@ -147,11 +147,25 @@ internal static class NdiNative
     public struct SendCreateSettings
     {
         public IntPtr p_ndi_name;     // const char*
-        public IntPtr p_groups;       // const char*
+        public IntPtr p_groups;       // const char*  (UTF-8, comma-separated; NULL = "Public")
         [MarshalAs(UnmanagedType.U1)] public bool clock_video;
         [MarshalAs(UnmanagedType.U1)] public bool clock_audio;
     }
 
+    /// <summary>
+    /// Mirrors <c>NDIlib_find_create_t</c>. Used to constrain which NDI groups a
+    /// finder will discover sources from. Passing NULL/<c>IntPtr.Zero</c> for the
+    /// settings pointer (or a struct with all fields zero) yields default behavior:
+    /// <c>show_local_sources=true</c>, groups=<c>"Public"</c>, no extra IPs.
+    /// </summary>
+    [StructLayout(LayoutKind.Sequential)]
+    public struct FindCreateSettings
+    {
+        [MarshalAs(UnmanagedType.U1)] public bool show_local_sources;
+        public IntPtr p_groups;       // const char*  (UTF-8, comma-separated; NULL = "Public")
+        public IntPtr p_extra_ips;    // const char*  (UTF-8, comma-separated; NULL = none)
+    }
+
     [StructLayout(LayoutKind.Sequential)]
     public struct VideoFrameV2
     {

src/TeamsISO.Engine/Controller/IIsoController.cs

@@ -17,6 +17,9 @@ public interface IIsoController : IAsyncDisposable
     /// <summary>Current global processing settings.</summary>
     FrameProcessingSettings GlobalSettings { get; }
 
+    /// <summary>Current NDI group settings (discovery + output groups).</summary>
+    NdiGroupSettings GroupSettings { get; }
+
     /// <summary>Starts discovery and supervises the runtime probe. Returns once startup is complete.</summary>
     Task StartAsync(CancellationToken cancellationToken);
 
@@ -31,4 +34,10 @@ public interface IIsoController : IAsyncDisposable
 
     /// <summary>Updates global processing settings and persists them. Currently does not restart running pipelines (Phase C wires that).</summary>
     Task SetGlobalSettingsAsync(FrameProcessingSettings settings, CancellationToken cancellationToken);
+
+    /// <summary>
+    /// Updates the NDI group configuration and persists it. Group changes apply on next process
+    /// restart — rebuilding finder/sender handles mid-flight would orphan running pipelines.
+    /// </summary>
+    Task SetGroupSettingsAsync(NdiGroupSettings groupSettings, CancellationToken cancellationToken);
 }

src/TeamsISO.Engine/Controller/IsoController.cs

@@ -35,6 +35,7 @@ public sealed class IsoController : IIsoController
     private readonly object _gate = new();
 
     private FrameProcessingSettings _settings;
+    private NdiGroupSettings _groupSettings;
     private CancellationTokenSource? _cts;
     private Task? _discoveryTask;
     private Task? _eventPumpTask;
@@ -42,6 +43,7 @@ public sealed class IsoController : IIsoController
     public IObservable<IReadOnlyList<Participant>> Participants => _participants.AsObservable();
     public IObservable<EngineAlert> Alerts => _alerts.AsObservable();
     public FrameProcessingSettings GlobalSettings { get { lock (_gate) return _settings; } }
+    public NdiGroupSettings GroupSettings { get { lock (_gate) return _groupSettings; } }
 
     public IsoController(
         INdiInterop interop,
@@ -63,12 +65,14 @@ public sealed class IsoController : IIsoController
 
         var loaded = configStore.Load();
         _settings = loaded.Global;
+        _groupSettings = loaded.GroupsOrDefault;
 
         _tracker = new ParticipantTracker(_renameWindow, clock ?? (() => DateTimeOffset.UtcNow));
         _discoveryChannel = Channel.CreateUnbounded<DiscoveryEvent>();
         _discovery = new NdiDiscoveryService(
             interop, _discoveryChannel.Writer,
-            loggerFactory.CreateLogger<NdiDiscoveryService>());
+            loggerFactory.CreateLogger<NdiDiscoveryService>(),
+            _groupSettings.DiscoveryGroups);
     }
 
     public async Task StartAsync(CancellationToken cancellationToken)
@@ -113,7 +117,17 @@ public sealed class IsoController : IIsoController
             throw new InvalidOperationException($"Participant {participantId} not currently visible on the network.");
 
         var output = customName ?? DefaultOutputName(participantId);
-        var config = new IsoPipelineConfig(participantId, p.CurrentSource.FullName, output, _settings);
+        string? outputGroups;
+        FrameProcessingSettings settingsSnapshot;
+        lock (_gate)
+        {
+            outputGroups = _groupSettings.OutputGroups;
+            settingsSnapshot = _settings;
+        }
+        var config = new IsoPipelineConfig(participantId, p.CurrentSource.FullName, output, settingsSnapshot)
+        {
+            OutputGroups = outputGroups,
+        };
         var pipeline = _pipelineFactory(config);
 
         lock (_gate) _pipelines[participantId] = pipeline;
@@ -139,19 +153,33 @@ public sealed class IsoController : IIsoController
         return PersistAssignmentsAsync(cancellationToken);
     }
 
+    /// <summary>
+    /// Updates the NDI group configuration. Note: existing finder/sender handles aren't
+    /// rebuilt — group changes take effect on the next process restart, since rebuilding
+    /// the live finder mid-flight would orphan in-flight participants. The settings
+    /// panel surfaces this caveat to the user.
+    /// </summary>
+    public Task SetGroupSettingsAsync(NdiGroupSettings groupSettings, CancellationToken cancellationToken)
+    {
+        lock (_gate) _groupSettings = groupSettings;
+        return PersistAssignmentsAsync(cancellationToken);
+    }
+
     private Task PersistAssignmentsAsync(CancellationToken cancellationToken)
     {
         try
         {
             FrameProcessingSettings settings;
+            NdiGroupSettings groupSettings;
             IReadOnlyList<IsoAssignment> assignments;
             lock (_gate)
             {
                 settings = _settings;
+                groupSettings = _groupSettings;
                 assignments = _pipelines.Keys.Select(id =>
                     new IsoAssignment(id, IsEnabled: true, CustomOutputName: null)).ToArray();
             }
-            _configStore.Save(new EngineConfig(settings, assignments));
+            _configStore.Save(new EngineConfig(settings, assignments, groupSettings));
         }
         catch (Exception ex)
         {

src/TeamsISO.Engine/Discovery/NdiDiscoveryService.cs

@@ -20,12 +20,13 @@ public sealed class NdiDiscoveryService
     public NdiDiscoveryService(
         INdiInterop interop,
         ChannelWriter<DiscoveryEvent> writer,
-        ILogger<NdiDiscoveryService> logger)
+        ILogger<NdiDiscoveryService> logger,
+        string? discoveryGroups = null)
     {
         _interop = interop;
         _writer = writer;
         _logger = logger;
-        _finder = interop.CreateFinder();
+        _finder = interop.CreateFinder(discoveryGroups);
     }
 
     /// <summary>

src/TeamsISO.Engine/Domain/EngineConfig.cs

@@ -2,8 +2,12 @@ namespace TeamsISO.Engine.Domain;
 
 public sealed record EngineConfig(
     FrameProcessingSettings Global,
-    IReadOnlyList<IsoAssignment> Assignments)
+    IReadOnlyList<IsoAssignment> Assignments,
+    NdiGroupSettings? NdiGroups = null)
 {
     public static readonly EngineConfig Default =
-        new(FrameProcessingSettings.Default, Array.Empty<IsoAssignment>());
+        new(FrameProcessingSettings.Default, Array.Empty<IsoAssignment>(), NdiGroupSettings.Default);
+
+    /// <summary>Returns <see cref="NdiGroups"/> or <see cref="NdiGroupSettings.Default"/> when null (legacy configs).</summary>
+    public NdiGroupSettings GroupsOrDefault => NdiGroups ?? NdiGroupSettings.Default;
 }

src/TeamsISO.Engine/Domain/NdiGroupSettings.cs

@@ -0,0 +1,27 @@
+namespace TeamsISO.Engine.Domain;
+
+/// <summary>
+/// Network-layer NDI configuration. Lets the operator place TeamsISO inside an NDI
+/// "transcoder" topology where the upstream (Teams) outputs are confined to a private
+/// group so they don't pollute the production network, while TeamsISO's own normalized
+/// outputs broadcast on the standard <c>"Public"</c> group consumed by the switcher.
+///
+/// Both fields are comma-separated lists of NDI group names. Whitespace around commas
+/// is tolerated. <c>null</c> or whitespace means "use the NDI default", which is the
+/// implicit <c>"Public"</c> group.
+/// </summary>
+/// <param name="DiscoveryGroups">
+/// Groups the engine's finder subscribes to when enumerating sources. Set this to
+/// the private group your Teams machine is configured to broadcast on (e.g.
+/// <c>"teamsiso-input"</c>) when you want to hide raw Teams outputs from the rest of
+/// the network.
+/// </param>
+/// <param name="OutputGroups">
+/// Groups TeamsISO's own ISO senders broadcast on. Leave at the default for the
+/// normal case where downstream switchers receive over the standard
+/// <c>"Public"</c> group; override only for split-audience setups.
+/// </param>
+public sealed record NdiGroupSettings(string? DiscoveryGroups, string? OutputGroups)
+{
+    public static readonly NdiGroupSettings Default = new(null, null);
+}

src/TeamsISO.Engine/Interop/INdiInterop.cs

@@ -9,7 +9,15 @@ namespace TeamsISO.Engine.Interop;
 public interface INdiInterop
 {
     // ----- Discovery -----
-    NdiFindHandle CreateFinder();
+
+    /// <summary>
+    /// Creates an NDI finder that observes sources advertised on the given groups.
+    /// </summary>
+    /// <param name="groups">
+    /// Comma-separated list of NDI group names to subscribe to. <c>null</c> or empty
+    /// uses the NDI default (<c>"Public"</c>). Whitespace around commas is tolerated.
+    /// </param>
+    NdiFindHandle CreateFinder(string? groups = null);
 
     /// <summary>Snapshots the currently-known sources visible to the finder.</summary>
     IReadOnlyList<string> GetCurrentSources(NdiFindHandle finder);
@@ -24,7 +32,17 @@ public interface INdiInterop
     RawFrame? CaptureFrame(NdiReceiverHandle receiver, int timeoutMs);
 
     // ----- Send -----
-    NdiSenderHandle CreateSender(string outputName);
+
+    /// <summary>
+    /// Creates an NDI sender broadcasting on the given groups.
+    /// </summary>
+    /// <param name="outputName">The NDI source name segment (the part inside parens).</param>
+    /// <param name="groups">
+    /// Comma-separated list of NDI group names to broadcast on. <c>null</c> or empty
+    /// uses the NDI default (<c>"Public"</c>).
+    /// </param>
+    NdiSenderHandle CreateSender(string outputName, string? groups = null);
+
     void SendFrame(NdiSenderHandle sender, ProcessedFrame frame);
 
     // ----- Runtime probe -----

src/TeamsISO.Engine/Pipeline/IsoPipeline.cs

@@ -164,7 +164,8 @@ public sealed class IsoPipeline : IAsyncDisposable
         using var receiver = new NdiReceiver(
             interop, config.SourceName, rawChannel.Writer, loggerFactory.CreateLogger<NdiReceiver>());
         using var sender = new NdiSender(
-            interop, config.OutputName, processedChannel.Reader, loggerFactory.CreateLogger<NdiSender>());
+            interop, config.OutputName, processedChannel.Reader, loggerFactory.CreateLogger<NdiSender>(),
+            config.OutputGroups);
 
         var processor = new FrameProcessor(
             config.Settings, scaler, new SolidFrameRenderer(),

src/TeamsISO.Engine/Pipeline/IsoPipelineConfig.cs

@@ -20,4 +20,11 @@ public sealed record IsoPipelineConfig(
 
     /// <summary>Bounded processed-frame channel capacity.</summary>
     public int ProcessedChannelCapacity { get; init; } = 2;
+
+    /// <summary>
+    /// NDI groups (comma-separated) the output sender broadcasts on. <c>null</c> means
+    /// "use the NDI default" (Public). Set per pipeline so the controller can drive it
+    /// from the global NdiGroupSettings without changing this record's identity contract.
+    /// </summary>
+    public string? OutputGroups { get; init; }
 }

src/TeamsISO.Engine/Pipeline/NdiSender.cs

@@ -20,13 +20,14 @@ public sealed class NdiSender : IDisposable
         INdiInterop interop,
         string outputName,
         ChannelReader<ProcessedFrame> input,
-        ILogger<NdiSender> logger)
+        ILogger<NdiSender> logger,
+        string? outputGroups = null)
     {
         _interop = interop;
         _outputName = outputName;
         _input = input;
         _logger = logger;
-        _handle = interop.CreateSender(outputName);
+        _handle = interop.CreateSender(outputName, outputGroups);
     }
 
     public long FramesSent => Interlocked.Read(ref _framesSent);

src/tests/TeamsISO.Engine.Tests/Controller/IsoControllerTests.cs

@@ -122,6 +122,54 @@ public class IsoControllerTests : IDisposable
         _store.Load().Global.Should().Be(newSettings);
     }
 
+    [Fact]
+    public async Task Constructor_PassesDiscoveryGroupsToFinder()
+    {
+        // Pre-populate the config store with a discovery-groups setting; the controller
+        // reads it on construction and feeds it into the finder.
+        _store.Save(new EngineConfig(
+            FrameProcessingSettings.Default,
+            Array.Empty<IsoAssignment>(),
+            new NdiGroupSettings(DiscoveryGroups: "teamsiso-input", OutputGroups: null)));
+
+        await using var controller = NewController();
+
+        _interop.LastFinderGroups.Should().Be("teamsiso-input");
+        controller.GroupSettings.DiscoveryGroups.Should().Be("teamsiso-input");
+    }
+
+    [Fact]
+    public async Task EnableIsoAsync_PassesOutputGroupsToPipelineConfig()
+    {
+        _store.Save(new EngineConfig(
+            FrameProcessingSettings.Default,
+            Array.Empty<IsoAssignment>(),
+            new NdiGroupSettings(DiscoveryGroups: null, OutputGroups: "Public,producers")));
+
+        await using var controller = NewController();
+        await controller.StartAsync(CancellationToken.None);
+
+        _interop.Sources.Add("PC1 (Teams - Jane)");
+        var pid = await WaitForFirstParticipantAsync(controller);
+
+        await controller.EnableIsoAsync(pid, customName: null, CancellationToken.None);
+
+        _factoryCalls.Should().HaveCount(1);
+        _factoryCalls[0].OutputGroups.Should().Be("Public,producers");
+    }
+
+    [Fact]
+    public async Task SetGroupSettingsAsync_PersistsToConfigStore()
+    {
+        await using var controller = NewController();
+        var newGroups = new NdiGroupSettings(DiscoveryGroups: "teamsiso-input", OutputGroups: "Public");
+
+        await controller.SetGroupSettingsAsync(newGroups, CancellationToken.None);
+
+        controller.GroupSettings.Should().Be(newGroups);
+        _store.Load().GroupsOrDefault.Should().Be(newGroups);
+    }
+
     [Fact]
     public async Task StartAsync_RuntimeProbeMismatch_RaisesAlert()
     {

src/tests/TeamsISO.Engine.Tests/Fakes/FakeNdiInterop.cs

@@ -17,7 +17,16 @@ public sealed class FakeNdiInterop : INdiInterop
     public Dictionary<string, int> ReceiverCreatedCount { get; } = new();
     public Dictionary<string, int> SenderCreatedCount { get; } = new();
 
-    public NdiFindHandle CreateFinder() => new FakeFindHandle();
+    /// <summary>Last <c>groups</c> string seen by <see cref="CreateFinder"/>; null = default Public.</summary>
+    public string? LastFinderGroups { get; private set; }
+    /// <summary>Per-output <c>groups</c> string seen by <see cref="CreateSender"/>; null = default Public.</summary>
+    public Dictionary<string, string?> SenderGroups { get; } = new();
+
+    public NdiFindHandle CreateFinder(string? groups = null)
+    {
+        LastFinderGroups = groups;
+        return new FakeFindHandle();
+    }
     public IReadOnlyList<string> GetCurrentSources(NdiFindHandle finder) => Sources.ToArray();
 
     public NdiReceiverHandle CreateReceiver(string sourceFullName)
@@ -35,9 +44,10 @@ public sealed class FakeNdiInterop : INdiInterop
         return null; // simulate timeout
     }
 
-    public NdiSenderHandle CreateSender(string outputName)
+    public NdiSenderHandle CreateSender(string outputName, string? groups = null)
     {
         SenderCreatedCount[outputName] = SenderCreatedCount.GetValueOrDefault(outputName) + 1;
+        SenderGroups[outputName] = groups;
         SentFrames.GetOrAdd(outputName, _ => new List<ProcessedFrame>());
         return new FakeSenderHandle(outputName);
     }