diff --git a/App.xaml b/App.xaml
index 2bf3cea..0c688a0 100644
--- a/App.xaml
+++ b/App.xaml
@@ -4,6 +4,10 @@
              xmlns:local="clr-namespace:ytLive"
              StartupUri="MainWindow.xaml">
     <Application.Resources>
-         
+        <ResourceDictionary>
+            <ResourceDictionary.MergedDictionaries>
+                <ResourceDictionary Source="Themes/Controls.xaml"/>
+            </ResourceDictionary.MergedDictionaries>
+        </ResourceDictionary>
     </Application.Resources>
 </Application>
diff --git a/App.xaml.cs b/App.xaml.cs
index 1ff0ff3..462beaa 100644
--- a/App.xaml.cs
+++ b/App.xaml.cs
@@ -1,13 +1,34 @@
-using System.Configuration;
-using System.Data;
-using System.Windows;
-
-namespace ytLive;
-
-/// <summary>
-/// Interaction logic for App.xaml
-/// </summary>
-public partial class App : Application
-{
-}
-
+using System.Windows;
+using System.Windows.Threading;
+using ytLive.Helpers;
+
+namespace ytLive;
+
+/// <summary>
+/// Interaction logic for App.xaml
+/// </summary>
+public partial class App : Application
+{
+    public App()
+    {
+        AppLog.Write("App ctor");
+    }
+
+    protected override void OnStartup(StartupEventArgs e)
+    {
+        // The app is a WinExe (no visible console) and is often debugged from
+        // WSL where it can't even run, so startup checkpoints and any unhandled
+        // exception are written to %APPDATA%\ytLlive\startup.log via AppLog.
+        AppDomain.CurrentDomain.UnhandledException += (_, args) =>
+            AppLog.Write(args.ExceptionObject is Exception ex
+                ? "AppDomain unhandled exception: " + ex
+                : "AppDomain unhandled exception object: " + args.ExceptionObject);
+
+        DispatcherUnhandledException += (_, args) =>
+            AppLog.Write(args.Exception, "Dispatcher unhandled exception");
+
+        AppLog.Write("App OnStartup begin");
+        base.OnStartup(e);
+        AppLog.Write("App OnStartup end");
+    }
+}
diff --git a/GoLiveWindow.xaml b/GoLiveWindow.xaml
index 5ec4d72..a662e23 100644
--- a/GoLiveWindow.xaml
+++ b/GoLiveWindow.xaml
@@ -7,58 +7,9 @@
         ShowInTaskbar="False" Background="#1a1a2e">
 
     <Window.Resources>
-        <BooleanToVisibilityConverter x:Key="BoolToVis"/>
-
-        <Style x:Key="GoLiveButton" TargetType="Button">
-            <Setter Property="Background" Value="#e94560"/>
-            <Setter Property="Foreground" Value="White"/>
-            <Setter Property="FontSize" Value="13"/>
-            <Setter Property="FontWeight" Value="SemiBold"/>
-            <Setter Property="Padding" Value="16,8"/>
-            <Setter Property="BorderThickness" Value="0"/>
-            <Setter Property="Cursor" Value="Hand"/>
-            <Setter Property="Template">
-                <Setter.Value>
-                    <ControlTemplate TargetType="Button">
-                        <Border Background="{TemplateBinding Background}"
-                                CornerRadius="4"
-                                Padding="{TemplateBinding Padding}">
-                            <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
-                        </Border>
-                    </ControlTemplate>
-                </Setter.Value>
-            </Setter>
-        </Style>
-
-        <Style x:Key="GoLiveButtonSecondary" TargetType="Button" BasedOn="{StaticResource GoLiveButton}">
-            <Setter Property="Background" Value="#16213e"/>
-        </Style>
-
-        <Style x:Key="GoLiveLabel" TargetType="TextBlock">
-            <Setter Property="Foreground" Value="#a0a0b0"/>
-            <Setter Property="FontSize" Value="12"/>
-            <Setter Property="Margin" Value="0,0,0,4"/>
-        </Style>
-
-        <Style x:Key="GoLiveTextBox" TargetType="TextBox">
-            <Setter Property="Background" Value="#0f3460"/>
-            <Setter Property="Foreground" Value="#e0e0e0"/>
-            <Setter Property="BorderThickness" Value="0"/>
-            <Setter Property="Padding" Value="8,6"/>
-            <Setter Property="FontSize" Value="13"/>
-            <Setter Property="CaretBrush" Value="White"/>
-            <Setter Property="Margin" Value="0,0,0,12"/>
-        </Style>
-
-        <Style x:Key="GoLiveCombo" TargetType="ComboBox">
-            <Setter Property="Background" Value="#0f3460"/>
-            <Setter Property="Foreground" Value="#e0e0e0"/>
-            <Setter Property="BorderThickness" Value="0"/>
-            <Setter Property="Padding" Value="8,6"/>
-            <Setter Property="FontSize" Value="13"/>
-            <Setter Property="Margin" Value="0,0,0,12"/>
-            <Setter Property="HorizontalContentAlignment" Value="Left"/>
-        </Style>
+        <ResourceDictionary>
+            <BooleanToVisibilityConverter x:Key="BoolToVis"/>
+        </ResourceDictionary>
     </Window.Resources>
 
     <Grid Margin="24">
@@ -77,17 +28,17 @@
             <TextBlock Text="STREAM DETAILS" FontSize="12" FontWeight="SemiBold"
                        Foreground="#a0a0b0" Margin="0,0,0,8"/>
 
-            <TextBlock Text="Title" Style="{StaticResource GoLiveLabel}"/>
-            <TextBox Style="{StaticResource GoLiveTextBox}"
+            <TextBlock Text="Title" Style="{StaticResource YtLabel}"/>
+            <TextBox Style="{StaticResource YtTextBox}" Margin="0,0,0,12"
                      Text="{Binding StreamTitle, UpdateSourceTrigger=PropertyChanged}"/>
 
-            <TextBlock Text="Description" Style="{StaticResource GoLiveLabel}"/>
-            <TextBox Style="{StaticResource GoLiveTextBox}" Height="60" AcceptsReturn="True"
+            <TextBlock Text="Description" Style="{StaticResource YtLabel}"/>
+            <TextBox Style="{StaticResource YtTextBox}" Height="60" AcceptsReturn="True" Margin="0,0,0,12"
                      Text="{Binding StreamDescription, UpdateSourceTrigger=PropertyChanged}"
                      VerticalScrollBarVisibility="Auto"/>
 
-            <TextBlock Text="Visibility" Style="{StaticResource GoLiveLabel}"/>
-            <ComboBox Style="{StaticResource GoLiveCombo}"
+            <TextBlock Text="Visibility" Style="{StaticResource YtLabel}"/>
+            <ComboBox Style="{StaticResource YtComboBox}" Margin="0,0,0,12"
                       ItemsSource="{Binding Visibilities}"
                       SelectedItem="{Binding Visibility}"/>
         </StackPanel>
@@ -95,9 +46,9 @@
         <!-- ACTIONS -->
         <StackPanel Grid.Row="3" Orientation="Horizontal" HorizontalAlignment="Right">
             <Button Content="Cancel" Command="{Binding CancelCommand}"
-                    Style="{StaticResource GoLiveButtonSecondary}" Margin="0,0,8,0"/>
+                    Style="{StaticResource YtButtonSecondary}" Margin="0,0,8,0"/>
             <Button Content="Start Stream" Command="{Binding StartCommand}"
-                    Style="{StaticResource GoLiveButton}" MinWidth="110"/>
+                    Style="{StaticResource YtButton}" MinWidth="110"/>
         </StackPanel>
     </Grid>
 </Window>
diff --git a/GoLiveWindow.xaml.cs b/GoLiveWindow.xaml.cs
index 8ae83c6..dba79cd 100644
--- a/GoLiveWindow.xaml.cs
+++ b/GoLiveWindow.xaml.cs
@@ -1,4 +1,5 @@
 using System.Windows;
+using ytLive.Helpers;
 using ytLive.ViewModels;
 
 namespace ytLive;
@@ -7,7 +8,9 @@ public partial class GoLiveWindow : Window
 {
     public GoLiveWindow(GoLiveViewModel viewModel)
     {
+        AppLog.Write("GoLiveWindow ctor: before InitializeComponent");
         InitializeComponent();
+        AppLog.Write("GoLiveWindow ctor: after InitializeComponent");
         DataContext = viewModel;
         viewModel.StartRequested += () => DialogResult = true;
         viewModel.CancelRequested += () => DialogResult = false;
diff --git a/Helpers/AppLog.cs b/Helpers/AppLog.cs
new file mode 100644
index 0000000..4bc7e0f
--- /dev/null
+++ b/Helpers/AppLog.cs
@@ -0,0 +1,40 @@
+using System.IO;
+
+namespace ytLive.Helpers;
+
+/// <summary>
+/// Minimal file logger used to diagnose startup/shutdown crashes on Windows,
+/// where the WPF app has no visible console. Writes to
+/// %APPDATA%\ytLlive\startup.log, appending synchronously so entries survive
+/// a hard crash.
+/// </summary>
+public static class AppLog
+{
+    private static readonly string LogPath = Path.Combine(
+        Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData),
+        "ytLlive",
+        "startup.log");
+
+    private static readonly object Gate = new();
+
+    public static void Write(string message)
+    {
+        try
+        {
+            lock (Gate)
+            {
+                Directory.CreateDirectory(Path.GetDirectoryName(LogPath)!);
+                File.AppendAllText(LogPath, $"{DateTime.Now:yyyy-MM-dd HH:mm:ss.fff} {message}{Environment.NewLine}");
+            }
+        }
+        catch
+        {
+            // Never let logging itself crash the app.
+        }
+    }
+
+    public static void Write(Exception exception, string message)
+    {
+        Write($"{message}: {exception}");
+    }
+}
diff --git a/Helpers/FocusPreservingListBox.cs b/Helpers/FocusPreservingListBox.cs
new file mode 100644
index 0000000..695d368
--- /dev/null
+++ b/Helpers/FocusPreservingListBox.cs
@@ -0,0 +1,72 @@
+using System.Collections.Specialized;
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Input;
+using System.Windows.Threading;
+
+namespace ytLive.Helpers;
+
+/// <summary>
+/// A ListBox that keeps selection and keyboard focus coherent when the
+/// selected item is deleted. Focus lands on the item now at the deleted
+/// position (the previous item when the last one was removed) or leaves
+/// the box entirely when it becomes empty. Drag-to-reorder is untouched.
+/// </summary>
+public class FocusPreservingListBox : ListBox
+{
+    /// <summary>
+    /// Predicate deciding which items the delete-focus fallback may land on
+    /// (e.g. skip hidden scenes). Null means every item is eligible.
+    /// </summary>
+    public Func<object, bool>? IsSelectable { get; set; }
+
+    protected override void OnItemsChanged(NotifyCollectionChangedEventArgs e)
+    {
+        base.OnItemsChanged(e);
+
+        if (e.Action != NotifyCollectionChangedAction.Remove) return;
+        var hadFocus = IsKeyboardFocusWithin || IsKeyboardFocused;
+        if (!hadFocus) return;
+        if (Mouse.Captured == this) return;
+
+        if (Items.Count == 0)
+        {
+            SelectedItem = null;
+            MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
+            return;
+        }
+
+        var targetIndex = FindSelectableIndex(Math.Clamp(e.OldStartingIndex, 0, Items.Count - 1));
+        if (targetIndex < 0)
+        {
+            SelectedItem = null;
+            return;
+        }
+
+        SelectedIndex = targetIndex;
+        var item = Items[targetIndex];
+
+        Dispatcher.BeginInvoke(DispatcherPriority.Loaded, () =>
+        {
+            ScrollIntoView(item);
+            if (ItemContainerGenerator.ContainerFromItem(item) is ListBoxItem container)
+                container.Focus();
+        });
+    }
+
+    private int FindSelectableIndex(int start)
+    {
+        for (var i = start; i >= 0; i--)
+            if (IsItemSelectable(i)) return i;
+        for (var i = start + 1; i < Items.Count; i++)
+            if (IsItemSelectable(i)) return i;
+        return -1;
+    }
+
+    private bool IsItemSelectable(int index)
+    {
+        if (index < 0 || index >= Items.Count) return false;
+        var item = Items[index];
+        return item != null && (IsSelectable?.Invoke(item) ?? true);
+    }
+}
diff --git a/Helpers/index.md b/Helpers/index.md
new file mode 100644
index 0000000..bcd1dbe
--- /dev/null
+++ b/Helpers/index.md
@@ -0,0 +1,17 @@
+# Helpers — index
+
+Cross-cutting utilities. See [`schema.md`](../schema.md) for the memory-map conventions.
+
+| File | Purpose |
+|------|---------|
+| `ViewModelBase.cs` | `INotifyPropertyChanged` + `SetProperty<T>()` — base for all ViewModels |
+| `RelayCommand.cs` | `ICommand` implementation for all button actions |
+| `AppLog.cs` | File logger to `%APPDATA%\ytLlive\startup.log`; startup checkpoints + unhandled-exception capture (the crash this map is named for) |
+| `FocusPreservingListBox.cs` | `ListBox` subclass that keeps selection/focus coherent when the selected item is deleted; `IsSelectable` predicate skips hidden scenes; drag-reorder guard |
+| `OAuthCredentials.cs` | Baked-in Google OAuth client ID/secret (desktop app; loopback callback) |
+| `ImageCache.cs` | Image byte caching (assets live in the DB) |
+| `InverseBoolToVisibilityConverter.cs` / `NotNullToVisibilityConverter.cs` | XAML value converters for visibility bindings |
+
+Related: [`Themes/Controls.xaml`](../Themes/Controls.xaml) styles the lists this
+class backs; [`Models/index.md`](../Models/index.md) and
+[`ViewModels/index.md`](../ViewModels/index.md) for the objects it works on.
diff --git a/MainWindow.xaml b/MainWindow.xaml
index 5c6af67..5a57213 100644
--- a/MainWindow.xaml
+++ b/MainWindow.xaml
@@ -4,6 +4,7 @@
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
         xmlns:vm="clr-namespace:ytLive.ViewModels"
+        xmlns:Helpers="clr-namespace:ytLive.Helpers"
         mc:Ignorable="d"
         Title="{Binding WindowTitle}" Height="720" Width="1280"
         MinWidth="1180" MinHeight="600"
@@ -11,6 +12,7 @@
         Background="#1a1a2e"
         WindowStartupLocation="CenterScreen"
         Closing="MainWindow_Closing"
+        Loaded="MainWindow_Loaded"
         PreviewMouseLeftButtonDown="Window_PreviewMouseLeftButtonDown">
 
     <Window.DataContext>
@@ -22,7 +24,8 @@
     </Window.TaskbarItemInfo>
 
     <Window.Resources>
-        <BooleanToVisibilityConverter x:Key="BoolToVis"/>
+        <ResourceDictionary>
+            <BooleanToVisibilityConverter x:Key="BoolToVis"/>
         <Helpers:InverseBoolToVisibilityConverter x:Key="InverseBoolToVis"
                                                   xmlns:Helpers="clr-namespace:ytLive.Helpers"/>
         <Helpers:NotNullToVisibilityConverter x:Key="NotNullToVis"
@@ -64,55 +67,6 @@
             </DrawingImage.Drawing>
         </DrawingImage>
 
-        <!-- Base button style -->
-        <Style x:Key="YtButton" TargetType="Button">
-            <Setter Property="Background" Value="#e94560"/>
-            <Setter Property="Foreground" Value="White"/>
-            <Setter Property="FontSize" Value="13"/>
-            <Setter Property="FontWeight" Value="SemiBold"/>
-            <Setter Property="Padding" Value="16,8"/>
-            <Setter Property="BorderThickness" Value="0"/>
-            <Setter Property="Cursor" Value="Hand"/>
-            <Setter Property="Template">
-                <Setter.Value>
-                    <ControlTemplate TargetType="Button">
-                        <Border Background="{TemplateBinding Background}"
-                                CornerRadius="4"
-                                Padding="{TemplateBinding Padding}">
-                            <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
-                        </Border>
-                    </ControlTemplate>
-                </Setter.Value>
-            </Setter>
-        </Style>
-
-        <Style x:Key="YtButtonSecondary" TargetType="Button" BasedOn="{StaticResource YtButton}">
-            <Setter Property="Background" Value="#16213e"/>
-        </Style>
-
-        <Style x:Key="IconButton" TargetType="Button">
-            <Setter Property="Background" Value="Transparent"/>
-            <Setter Property="BorderThickness" Value="0"/>
-            <Setter Property="Padding" Value="4"/>
-            <Setter Property="Cursor" Value="Hand"/>
-            <Setter Property="Template">
-                <Setter.Value>
-                    <ControlTemplate TargetType="Button">
-                        <Border Background="{TemplateBinding Background}"
-                                CornerRadius="3"
-                                Padding="{TemplateBinding Padding}">
-                            <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
-                        </Border>
-                    </ControlTemplate>
-                </Setter.Value>
-            </Setter>
-            <Style.Triggers>
-                <Trigger Property="IsMouseOver" Value="True">
-                    <Setter Property="Background" Value="#26ffffff"/>
-                </Trigger>
-            </Style.Triggers>
-        </Style>
-
         <!-- Eye icon: open when visible, slashed when hidden -->
         <Style x:Key="EyeIconStyle" TargetType="Path">
             <Setter Property="Data" Value="M12,4.5C7,4.5 2.73,7.61 1,12c1.73,4.39 6,7.5 11,7.5s9.27,-3.11 11,-7.5c-1.73,-4.39 -6,-7.5 -11,-7.5zM12,17c-2.76,0 -5,-2.24 -5,-5s2.24,-5 5,-5 5,2.24 5,5 -2.24,5 -5,5zM12,9c-1.66,0 -3,1.34 -3,3s1.34,3 3,3 3,-1.34 3,-3 -1.34,-3 -3,-3z"/>
@@ -131,36 +85,7 @@
                 </DataTrigger>
             </Style.Triggers>
         </Style>
-
-        <Style x:Key="YtTextBox" TargetType="TextBox">
-            <Setter Property="Background" Value="#0f3460"/>
-            <Setter Property="Foreground" Value="#e0e0e0"/>
-            <Setter Property="BorderThickness" Value="0"/>
-            <Setter Property="Padding" Value="8,6"/>
-            <Setter Property="FontSize" Value="13"/>
-            <Setter Property="CaretBrush" Value="White"/>
-        </Style>
-
-        <Style x:Key="YtComboBox" TargetType="ComboBox">
-            <Setter Property="Background" Value="#0f3460"/>
-            <Setter Property="Foreground" Value="#e0e0e0"/>
-            <Setter Property="BorderThickness" Value="0"/>
-            <Setter Property="Padding" Value="8,6"/>
-            <Setter Property="FontSize" Value="13"/>
-            <Setter Property="HorizontalContentAlignment" Value="Left"/>
-        </Style>
-
-        <Style x:Key="YtLabel" TargetType="TextBlock">
-            <Setter Property="Foreground" Value="#a0a0b0"/>
-            <Setter Property="FontSize" Value="12"/>
-        </Style>
-
-        <Style x:Key="SectionHeader" TargetType="TextBlock">
-            <Setter Property="Foreground" Value="#e0e0e0"/>
-            <Setter Property="FontSize" Value="14"/>
-            <Setter Property="FontWeight" Value="SemiBold"/>
-            <Setter Property="Margin" Value="0,0,0,8"/>
-        </Style>
+        </ResourceDictionary>
     </Window.Resources>
 
     <Grid>
@@ -244,7 +169,7 @@
                         </Button>
                     </StackPanel>
 
-                    <ListBox x:Name="SceneList" Grid.Row="1" Background="Transparent" BorderThickness="0"
+                    <Helpers:FocusPreservingListBox x:Name="SceneList" Grid.Row="1" Background="Transparent" BorderThickness="0"
                              ItemsSource="{Binding Scenes}"
                              SelectedItem="{Binding ActiveScene}"
                              SelectionChanged="SceneList_SelectionChanged"
@@ -252,8 +177,8 @@
                              PreviewMouseMove="List_PreviewMouseMove"
                              PreviewMouseLeftButtonUp="List_PreviewMouseLeftButtonUp"
                              Foreground="#e0e0e0" FontSize="13">
-                        <ListBox.ItemContainerStyle>
-                            <Style TargetType="ListBoxItem">
+                        <Helpers:FocusPreservingListBox.ItemContainerStyle>
+                            <Style TargetType="ListBoxItem" BasedOn="{StaticResource YtListBoxItem}">
                                 <Setter Property="HorizontalContentAlignment" Value="Stretch"/>
                                 <Style.Triggers>
                                     <DataTrigger Binding="{Binding IsHidden}" Value="True">
@@ -261,7 +186,7 @@
                                     </DataTrigger>
                                 </Style.Triggers>
                             </Style>
-                        </ListBox.ItemContainerStyle>
+                        </Helpers:FocusPreservingListBox.ItemContainerStyle>
                         <ListBox.ItemTemplate>
                             <DataTemplate>
                                 <Grid Margin="0,2">
@@ -326,7 +251,7 @@
                                 </Grid>
                             </DataTemplate>
                         </ListBox.ItemTemplate>
-                    </ListBox>
+                    </Helpers:FocusPreservingListBox>
 
                     <!-- Sources (for active scene) -->
                     <StackPanel Grid.Row="2" Orientation="Horizontal" Margin="0,12,0,0">
@@ -347,18 +272,18 @@
                         </Button>
                     </StackPanel>
 
-                    <ListBox x:Name="SourceList" Grid.Row="3" Background="Transparent" BorderThickness="0"
+                    <Helpers:FocusPreservingListBox x:Name="SourceList" Grid.Row="3" Background="Transparent" BorderThickness="0"
                              ItemsSource="{Binding ActiveScene.Sources}"
                              SelectedItem="{Binding SelectedSource, Mode=TwoWay}"
                              PreviewMouseLeftButtonDown="List_PreviewMouseLeftButtonDown"
                              PreviewMouseMove="List_PreviewMouseMove"
                              PreviewMouseLeftButtonUp="List_PreviewMouseLeftButtonUp"
                              Foreground="#e0e0e0" FontSize="13">
-                        <ListBox.ItemContainerStyle>
-                            <Style TargetType="ListBoxItem">
+                        <Helpers:FocusPreservingListBox.ItemContainerStyle>
+                            <Style TargetType="ListBoxItem" BasedOn="{StaticResource YtListBoxItem}">
                                 <Setter Property="HorizontalContentAlignment" Value="Stretch"/>
                             </Style>
-                        </ListBox.ItemContainerStyle>
+                        </Helpers:FocusPreservingListBox.ItemContainerStyle>
                         <ListBox.ItemTemplate>
                             <DataTemplate>
                                 <Grid Margin="0,2">
@@ -379,7 +304,7 @@
                                 </Grid>
                             </DataTemplate>
                         </ListBox.ItemTemplate>
-                    </ListBox>
+                    </Helpers:FocusPreservingListBox>
 
                     <TextBlock Grid.Row="3" Text="No sources yet" Foreground="#555" FontSize="12"
                                HorizontalAlignment="Center" VerticalAlignment="Center"
@@ -515,6 +440,7 @@
 
                     <ListBox Grid.Row="1" Background="Transparent" BorderThickness="0"
                              ItemsSource="{Binding ChatMessages}"
+                             ItemContainerStyle="{StaticResource YtListBoxItem}"
                              Visibility="{Binding ShowChatInactiveMessage, Converter={StaticResource InverseBoolToVis}}"
                              Foreground="#e0e0e0" FontSize="12">
                         <ListBox.ItemTemplate>
@@ -567,7 +493,14 @@
                                Foreground="#e94560" Margin="20,0,0,0"/>
                 </StackPanel>
 
-                <Button Grid.Column="1" ToolTip="Menu" Style="{StaticResource IconButton}" Click="GearButton_Click">
+                <StackPanel Grid.Column="1" Orientation="Horizontal" VerticalAlignment="Center">
+                    <ComboBox Style="{StaticResource YtComboBox}" MinWidth="150"
+                              ItemsSource="{Binding QualityOptions}"
+                              SelectedItem="{Binding SelectedQuality}"
+                              DisplayMemberPath="Label"
+                              ToolTip="{Binding ResolutionHelp}"
+                              IsEnabled="{Binding IsOffline}"/>
+                    <Button ToolTip="Menu" Style="{StaticResource IconButton}" Click="GearButton_Click">
                     <Button.ContextMenu>
                         <ContextMenu DataContext="{Binding PlacementTarget.DataContext, RelativeSource={RelativeSource Self}}">
                             <MenuItem Header="Save Layout" Command="{Binding SaveLayoutCommand}"/>
@@ -582,7 +515,8 @@
                     </Button.ContextMenu>
                     <Path Data="M19.14,12.94c0.04,-0.3 0.06,-0.61 0.06,-0.94c0,-0.32 -0.02,-0.64 -0.07,-0.94l2.03,-1.58c0.18,-0.14 0.23,-0.41 0.12,-0.61l-1.92,-3.32c-0.12,-0.22 -0.37,-0.29 -0.59,-0.22l-2.39,0.96c-0.5,-0.38 -1.03,-0.7 -1.62,-0.94L14.4,2.81c-0.04,-0.24 -0.24,-0.41 -0.48,-0.41h-3.84c-0.24,0 -0.43,0.17 -0.47,0.41L9.25,5.35C8.66,5.59 8.12,5.92 7.63,6.29L5.24,5.33c-0.22,-0.08 -0.47,0 -0.59,0.22L2.74,8.87C2.62,9.08 2.66,9.34 2.86,9.48l2.03,1.58C4.84,11.36 4.8,11.69 4.8,12s0.02,0.64 0.07,0.94l-2.03,1.58c-0.18,0.14 -0.23,0.41 -0.12,0.61l1.92,3.32c0.12,0.22 0.37,0.29 0.59,0.22l2.39,-0.96c0.5,0.38 1.03,0.7 1.62,0.94l0.36,2.54c0.05,0.24 0.24,0.41 0.48,0.41h3.84c0.24,0 0.44,-0.17 0.47,-0.41l0.36,-2.54c0.59,-0.24 1.13,-0.56 1.62,-0.94l2.39,0.96c0.22,0.08 0.47,0 0.59,-0.22l1.92,-3.32c0.12,-0.22 0.07,-0.47 -0.12,-0.61L19.14,12.94zM12,15.6c-1.98,0 -3.6,-1.62 -3.6,-3.6s1.62,-3.6 3.6,-3.6s3.6,1.62 3.6,3.6S13.98,15.6 12,15.6z"
                           Fill="#d0d0d0" Width="16" Height="16" Stretch="Uniform"/>
-                </Button>
+                    </Button>
+                </StackPanel>
             </Grid>
         </Border>
 
@@ -638,16 +572,6 @@
 
                         <TextBlock Text="These prefill the Start Stream dialog. Scene and stream settings are stored on the stream itself."
                                    Style="{StaticResource YtLabel}" Margin="0,16,0,0" TextWrapping="Wrap"/>
-
-                        <TextBlock Text="STREAM SETTINGS" Style="{StaticResource SectionHeader}" Margin="0,20,0,8"/>
-
-                        <TextBlock Text="Stream Quality" Style="{StaticResource YtLabel}" Margin="0,0,0,4"/>
-                        <ComboBox Style="{StaticResource YtComboBox}" HorizontalAlignment="Left" MinWidth="140"
-                                  ItemsSource="{Binding StreamQualities}"
-                                  SelectedItem="{Binding StreamQuality}"/>
-
-                        <TextBlock Text="Switching quality updates the stream metrics in the status bar. 1080p60 is the standard."
-                                   Style="{StaticResource YtLabel}" Margin="0,16,0,0" TextWrapping="Wrap"/>
                     </StackPanel>
 
                     <!-- Report Bug -->
diff --git a/MainWindow.xaml.cs b/MainWindow.xaml.cs
index 07d1f1f..e204418 100644
--- a/MainWindow.xaml.cs
+++ b/MainWindow.xaml.cs
@@ -4,6 +4,7 @@ using System.Windows;
 using System.Windows.Controls;
 using System.Windows.Input;
 using System.Windows.Media;
+using ytLive.Helpers;
 using ytLive.Models;
 using ytLive.ViewModels;
 
@@ -15,11 +16,21 @@ public partial class MainWindow : Window
 
     public MainWindow()
     {
+        AppLog.Write("MainWindow ctor: before InitializeComponent");
         InitializeComponent();
+        AppLog.Write("MainWindow ctor: after InitializeComponent");
         _viewModel = (MainViewModel)DataContext;
         _viewModel.PropertyChanged += OnViewModelPropertyChanged;
+        // When a focused scene is deleted, never land focus on a hidden scene.
+        SceneList.IsSelectable = item => item is Scene { IsHidden: false };
         UpdateTaskbarOverlay();
         UpdateSelectionOverlay();
+        AppLog.Write("MainWindow ctor: end");
+    }
+
+    private void MainWindow_Loaded(object sender, RoutedEventArgs e)
+    {
+        AppLog.Write("MainWindow loaded");
     }
 
     private void OnViewModelPropertyChanged(object? sender, PropertyChangedEventArgs e)
diff --git a/Models/QualityOption.cs b/Models/QualityOption.cs
new file mode 100644
index 0000000..229626e
--- /dev/null
+++ b/Models/QualityOption.cs
@@ -0,0 +1,10 @@
+namespace ytLive.Models;
+
+/// <summary>
+/// A resolution tier offered by the bottom-bar dropdown. Bitrate is Mbps.
+/// </summary>
+public sealed record QualityOption(string Display, int Fps, double Bitrate)
+{
+    /// <summary>Self-documenting label, e.g. "1080p60 (8Mbps)".</summary>
+    public string Label => $"{Display} ({Bitrate:0.#}Mbps)";
+}
diff --git a/Models/index.md b/Models/index.md
new file mode 100644
index 0000000..66768db
--- /dev/null
+++ b/Models/index.md
@@ -0,0 +1,15 @@
+# Models — index
+
+Plain data types. No logic beyond what a property can carry. See
+[`schema.md`](../schema.md) for the memory-map conventions.
+
+| File | Purpose |
+|------|---------|
+| `Scene.cs` | A scene: `Name`, `IsHidden`, `IsChatScene`, `IsEditing`, `Sources` collection |
+| `Source.cs` | A source: `SourceType` enum (Image/Webcam/Screen/Background/Text), `X`/`Y`/`Width`/`Height`, `Opacity`, `IsEnabled`, `ImageSource`, asset identity |
+| `QualityOption.cs` | Resolution tier record `(Display, Fps, Bitrate)`; `Label` formats as `1080p60 (8Mbps)` — drives the bottom-bar dropdown |
+| `StreamConfig.cs` | `StreamConfig` (note: `TargetBitrate`/`Resolution` defaults are stale — not yet wired to the dropdown), `StreamHealth` (bitrate/FPS/dropped/duration), `StreamStatus` enum |
+| `YouTube.cs` | `YouTubeChannel` and `ChatMessage` (chat feed) |
+
+Related: [`ViewModels/index.md`](../ViewModels/index.md) consume these;
+[`Services/LayoutStore.cs`](../Services/LayoutStore.cs) persists `Scene`/`Source`.
diff --git a/README.md b/README.md
index c5feed6..7843bcf 100644
--- a/README.md
+++ b/README.md
@@ -41,8 +41,14 @@ dotnet run
 
 | Path | Role |
 |------|------|
-| `Models/` | Scene, Source, StreamConfig, StreamHealth, YouTube channel/chat |
-| `ViewModels/` | MainViewModel — scenes, stream controls, chat |
-| `Services/` | YouTubeAuthService (OAuth2), YouTubeStreamService (broadcast/health), YouTubeChatService (chat polling) |
-| `Helpers/` | ViewModelBase, RelayCommand |
+| `Models/` | Scene, Source, QualityOption, StreamConfig, StreamHealth, YouTube channel/chat |
+| `ViewModels/` | MainViewModel — scenes, stream controls, chat; GoLiveViewModel, ReuseImageViewModel |
+| `Services/` | YouTubeAuthService (OAuth2), YouTubeStreamService (broadcast/health), YouTubeChatService (chat polling), LayoutStore (SQLite) |
+| `Helpers/` | ViewModelBase, RelayCommand, ImageCache, AppLog, FocusPreservingListBox, OAuthCredentials |
+| `Themes/` | `Controls.xaml` — the dark-theme control styles, merged once in `App.xaml` |
 | `MainWindow.xaml` | Dark-theme main UI: scene/source panel, preview, chat, status bar |
+
+## Docs (memory map)
+
+`schema.md` defines the conventions; `ai.md` is the AI/session guide;
+`TASKS.md` is the task queue. Each code directory carries an `index.md`.
diff --git a/ReuseImageDialog.xaml b/ReuseImageDialog.xaml
index 8c55755..930c372 100644
--- a/ReuseImageDialog.xaml
+++ b/ReuseImageDialog.xaml
@@ -7,30 +7,7 @@
         ShowInTaskbar="False" Background="#1a1a2e">
 
     <Window.Resources>
-        <Style x:Key="GoLiveButton" TargetType="Button">
-            <Setter Property="Background" Value="#e94560"/>
-            <Setter Property="Foreground" Value="White"/>
-            <Setter Property="FontSize" Value="13"/>
-            <Setter Property="FontWeight" Value="SemiBold"/>
-            <Setter Property="Padding" Value="16,8"/>
-            <Setter Property="BorderThickness" Value="0"/>
-            <Setter Property="Cursor" Value="Hand"/>
-            <Setter Property="Template">
-                <Setter.Value>
-                    <ControlTemplate TargetType="Button">
-                        <Border Background="{TemplateBinding Background}"
-                                CornerRadius="4"
-                                Padding="{TemplateBinding Padding}">
-                            <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
-                        </Border>
-                    </ControlTemplate>
-                </Setter.Value>
-            </Setter>
-        </Style>
-
-        <Style x:Key="GoLiveButtonSecondary" TargetType="Button" BasedOn="{StaticResource GoLiveButton}">
-            <Setter Property="Background" Value="#16213e"/>
-        </Style>
+        <ResourceDictionary>
 
         <Style x:Key="CandidateItem" TargetType="ListBoxItem">
             <Setter Property="HorizontalContentAlignment" Value="Stretch"/>
@@ -53,6 +30,7 @@
                 </Setter.Value>
             </Setter>
         </Style>
+        </ResourceDictionary>
     </Window.Resources>
 
     <Grid Margin="24">
@@ -95,11 +73,11 @@
 
         <StackPanel Grid.Row="3" Orientation="Horizontal" HorizontalAlignment="Right" Margin="0,12,0,0">
             <Button Content="New Image…" Command="{Binding NewImageCommand}"
-                    Style="{StaticResource GoLiveButtonSecondary}" Margin="0,0,8,0"/>
+                    Style="{StaticResource YtButtonSecondary}" Margin="0,0,8,0"/>
             <Button Content="Cancel" Command="{Binding CancelCommand}"
-                    Style="{StaticResource GoLiveButtonSecondary}" Margin="0,0,8,0"/>
+                    Style="{StaticResource YtButtonSecondary}" Margin="0,0,8,0"/>
             <Button Content="Use Selected" Command="{Binding UseSelectedCommand}"
-                    Style="{StaticResource GoLiveButton}" MinWidth="110"/>
+                    Style="{StaticResource YtButton}" MinWidth="110"/>
         </StackPanel>
     </Grid>
 </Window>
diff --git a/ReuseImageDialog.xaml.cs b/ReuseImageDialog.xaml.cs
index 884a29b..5c2f730 100644
--- a/ReuseImageDialog.xaml.cs
+++ b/ReuseImageDialog.xaml.cs
@@ -1,4 +1,5 @@
 using System.Windows;
+using ytLive.Helpers;
 using ytLive.ViewModels;
 
 namespace ytLive;
@@ -10,7 +11,9 @@ public partial class ReuseImageDialog : Window
 
     public ReuseImageDialog(ReuseImageViewModel viewModel)
     {
+        AppLog.Write("ReuseImageDialog ctor: before InitializeComponent");
         InitializeComponent();
+        AppLog.Write("ReuseImageDialog ctor: after InitializeComponent");
         DataContext = viewModel;
         viewModel.ReuseRequested += () =>
         {
diff --git a/Services/index.md b/Services/index.md
new file mode 100644
index 0000000..636bc27
--- /dev/null
+++ b/Services/index.md
@@ -0,0 +1,15 @@
+# Services — index
+
+External-facing logic: YouTube API, persistence. See
+[`schema.md`](../schema.md) for the memory-map conventions.
+
+| File | Purpose |
+|------|---------|
+| `YouTubeAuthService.cs` | OAuth2 via Google: loopback callback (`http://localhost:8765/oauth2/callback`), token exchange, refresh, channel fetch. **Complete — but no token persistence yet** (DPAPI planned) |
+| `YouTubeStreamService.cs` | Broadcast/stream management via the v3 API (`enableAutoStart/Stop`). **Not yet switched to the `variable` reusable stream** |
+| `YouTubeChatService.cs` | Polls `liveChat/messages`, raises `MessageReceived`; `IDisposable` |
+| `LayoutStore.cs` | SQLite persistence (`Microsoft.Data.Sqlite`) at `%APPDATA%\ytLlive\ytLlive.db`; assets stored as BLOBs keyed by SHA-256 content hash; save/open layout files |
+
+Related: constructed in [`ViewModels/MainViewModel.cs`](../ViewModels/MainViewModel.cs)
+(no DI container yet). Models in [`Models/index.md`](../Models/index.md).
+OAuth credentials live in [`Helpers/OAuthCredentials.cs`](../Helpers/OAuthCredentials.cs).
diff --git a/TASKS.md b/TASKS.md
index f6ba9f2..895b958 100644
--- a/TASKS.md
+++ b/TASKS.md
@@ -1,5 +1,8 @@
 # ytLlive — Task List
 
+> Task queue and authoritative research. Memory-map conventions: [`schema.md`](schema.md);
+> architecture/decisions: [`ai.md`](ai.md). Update statuses here whenever a task moves.
+
 ## YouTube Live API — research facts (authoritative, v3 build)
 
 Lifecycle: `created → ready → [testing] → live → complete` (transitional `liveStarting` / `testStarting`).
@@ -71,9 +74,9 @@ Lifecycle: `created → ready → [testing] → live → complete` (transitional
 
 ### Status: 🔶 UI flow done — auth wiring pending
 - ✅ Two-state Start/End Stream button, go-live dialog (account + title/description/visibility), red top bar, pulsing LIVE badge + elapsed timer, preview glow, taskbar red dot
-- ⬜ Real OAuth2 with the baked-in Google credentials (desktop client type; loopback callback, no redirect registration)
+- ✅ Real OAuth2 wiring — baked-in Google credentials (desktop client; loopback callback) + `YouTubeAuthService` complete: browser launch, `HttpListener` callback, token exchange, refresh, channel fetch
 - ⬜ Token persistence via Windows DPAPI, reload on startup
-- ⬜ Account sign-in/change wired to YouTubeAuthService (currently simulated in GoLiveViewModel)
+- ⬜ Account sign-in/change surfaced in the GoLive dialog (GoLiveViewModel still simulates it)
 
 ---
 
diff --git a/Themes/Controls.xaml b/Themes/Controls.xaml
new file mode 100644
index 0000000..aede043
--- /dev/null
+++ b/Themes/Controls.xaml
@@ -0,0 +1,458 @@
+<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+
+    <!-- Base button style -->
+    <Style x:Key="YtButton" TargetType="Button">
+        <Setter Property="Background" Value="#e94560"/>
+        <Setter Property="Foreground" Value="White"/>
+        <Setter Property="FontSize" Value="13"/>
+        <Setter Property="FontWeight" Value="SemiBold"/>
+        <Setter Property="Padding" Value="16,8"/>
+        <Setter Property="BorderThickness" Value="0"/>
+        <Setter Property="Cursor" Value="Hand"/>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="Button">
+                    <Grid>
+                        <Border x:Name="Bd" Background="{TemplateBinding Background}"
+                                CornerRadius="4"
+                                Padding="{TemplateBinding Padding}">
+                            <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
+                        </Border>
+                        <Border x:Name="Glow" Background="White" CornerRadius="4" Opacity="0"/>
+                    </Grid>
+                    <ControlTemplate.Triggers>
+                        <Trigger Property="IsMouseOver" Value="True">
+                            <Setter TargetName="Glow" Property="Opacity" Value="0.08"/>
+                        </Trigger>
+                        <Trigger Property="IsPressed" Value="True">
+                            <Setter TargetName="Glow" Property="Opacity" Value="0.16"/>
+                        </Trigger>
+                        <Trigger Property="IsEnabled" Value="False">
+                            <Setter Property="Opacity" Value="0.45"/>
+                        </Trigger>
+                    </ControlTemplate.Triggers>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
+    <Style x:Key="YtButtonSecondary" TargetType="Button" BasedOn="{StaticResource YtButton}">
+        <Setter Property="Background" Value="#16213e"/>
+    </Style>
+
+    <Style x:Key="IconButton" TargetType="Button">
+        <Setter Property="Background" Value="Transparent"/>
+        <Setter Property="BorderThickness" Value="0"/>
+        <Setter Property="Padding" Value="4"/>
+        <Setter Property="Cursor" Value="Hand"/>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="Button">
+                    <Border Background="{TemplateBinding Background}"
+                            CornerRadius="3"
+                            Padding="{TemplateBinding Padding}">
+                        <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
+                    </Border>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+        <Style.Triggers>
+            <Trigger Property="IsMouseOver" Value="True">
+                <Setter Property="Background" Value="#26ffffff"/>
+            </Trigger>
+        </Style.Triggers>
+    </Style>
+
+    <Style x:Key="YtTextBox" TargetType="TextBox">
+        <Setter Property="Background" Value="#0f3460"/>
+        <Setter Property="Foreground" Value="#e0e0e0"/>
+        <Setter Property="BorderBrush" Value="#2a3a5e"/>
+        <Setter Property="BorderThickness" Value="1"/>
+        <Setter Property="Padding" Value="8,6"/>
+        <Setter Property="FontSize" Value="13"/>
+        <Setter Property="CaretBrush" Value="White"/>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="TextBox">
+                    <Border x:Name="Bd" Background="{TemplateBinding Background}"
+                            BorderBrush="{TemplateBinding BorderBrush}"
+                            BorderThickness="{TemplateBinding BorderThickness}"
+                            CornerRadius="4" Padding="{TemplateBinding Padding}">
+                        <ScrollViewer x:Name="PART_ContentHost" Margin="0"/>
+                    </Border>
+                    <ControlTemplate.Triggers>
+                        <Trigger Property="IsMouseOver" Value="True">
+                            <Setter TargetName="Bd" Property="BorderBrush" Value="#3d5076"/>
+                        </Trigger>
+                        <Trigger Property="IsKeyboardFocusWithin" Value="True">
+                            <Setter TargetName="Bd" Property="BorderBrush" Value="#e94560"/>
+                        </Trigger>
+                        <Trigger Property="IsEnabled" Value="False">
+                            <Setter TargetName="Bd" Property="Opacity" Value="0.45"/>
+                        </Trigger>
+                    </ControlTemplate.Triggers>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
+    <Style x:Key="YtComboBox" TargetType="ComboBox">
+        <Setter Property="Foreground" Value="#e0e0e0"/>
+        <Setter Property="FontSize" Value="13"/>
+        <Setter Property="Background" Value="#0f3460"/>
+        <Setter Property="BorderBrush" Value="#2a3a5e"/>
+        <Setter Property="BorderThickness" Value="1"/>
+        <Setter Property="Padding" Value="8,6"/>
+        <Setter Property="MinHeight" Value="30"/>
+        <Setter Property="HorizontalContentAlignment" Value="Left"/>
+        <Setter Property="SnapsToDevicePixels" Value="True"/>
+        <Setter Property="ScrollViewer.CanContentScroll" Value="True"/>
+        <Setter Property="ItemContainerStyle">
+            <Setter.Value>
+                <Style TargetType="ComboBoxItem">
+                    <Setter Property="Foreground" Value="#e0e0e0"/>
+                    <Setter Property="FontSize" Value="13"/>
+                    <Setter Property="Padding" Value="10,7"/>
+                    <Setter Property="HorizontalContentAlignment" Value="Left"/>
+                    <Setter Property="Background" Value="Transparent"/>
+                    <Setter Property="Template">
+                        <Setter.Value>
+                            <ControlTemplate TargetType="ComboBoxItem">
+                                <Border x:Name="Bd" Background="{TemplateBinding Background}"
+                                        CornerRadius="3" Margin="0,1" Padding="{TemplateBinding Padding}">
+                                    <ContentPresenter/>
+                                </Border>
+                                <ControlTemplate.Triggers>
+                                    <Trigger Property="IsHighlighted" Value="True">
+                                        <Setter TargetName="Bd" Property="Background" Value="#26ffffff"/>
+                                    </Trigger>
+                                    <Trigger Property="IsSelected" Value="True">
+                                        <Setter TargetName="Bd" Property="Background" Value="#1a3a66"/>
+                                        <Setter Property="Foreground" Value="White"/>
+                                    </Trigger>
+                                </ControlTemplate.Triggers>
+                            </ControlTemplate>
+                        </Setter.Value>
+                    </Setter>
+                </Style>
+            </Setter.Value>
+        </Setter>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="ComboBox">
+                    <Grid>
+                        <Border x:Name="Chrome" Background="{TemplateBinding Background}"
+                                BorderBrush="{TemplateBinding BorderBrush}"
+                                BorderThickness="{TemplateBinding BorderThickness}"
+                                CornerRadius="4"/>
+                        <ContentPresenter x:Name="ContentSite" IsHitTestVisible="False"
+                                          Margin="{TemplateBinding Padding}"
+                                          HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
+                                          VerticalAlignment="Center"
+                                          Content="{TemplateBinding SelectionBoxItem}"
+                                          ContentTemplate="{TemplateBinding SelectionBoxItemTemplate}"
+                                          ContentTemplateSelector="{TemplateBinding ItemTemplateSelector}"/>
+                        <ToggleButton x:Name="ToggleButton" Focusable="False" ClickMode="Press"
+                                      Background="Transparent" BorderThickness="0"
+                                      IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}">
+                            <ToggleButton.Template>
+                                <ControlTemplate TargetType="ToggleButton">
+                                    <Grid Background="Transparent">
+                                        <Path x:Name="Chevron" Data="M0,0 L4,4 L8,0" Stroke="#8a93a8"
+                                              StrokeThickness="1.5" HorizontalAlignment="Right"
+                                              VerticalAlignment="Center" Margin="0,0,10,0"/>
+                                    </Grid>
+                                    <ControlTemplate.Triggers>
+                                        <Trigger Property="IsMouseOver" Value="True">
+                                            <Setter TargetName="Chevron" Property="Stroke" Value="#c8d0e0"/>
+                                        </Trigger>
+                                        <Trigger Property="IsEnabled" Value="False">
+                                            <Setter Property="Opacity" Value="0.45"/>
+                                        </Trigger>
+                                    </ControlTemplate.Triggers>
+                                </ControlTemplate>
+                            </ToggleButton.Template>
+                        </ToggleButton>
+                        <Popup x:Name="PART_Popup" Placement="Bottom" AllowsTransparency="True"
+                               PopupAnimation="Fade" StaysOpen="False"
+                               IsOpen="{TemplateBinding IsDropDownOpen}">
+                            <Border Background="#16213e" BorderBrush="#2a3a5e" BorderThickness="1"
+                                    CornerRadius="5" Padding="2" Margin="0,4,0,0"
+                                    SnapsToDevicePixels="True">
+                                <ScrollViewer MaxHeight="{TemplateBinding MaxDropDownHeight}"
+                                              ScrollViewer.CanContentScroll="True">
+                                    <ItemsPresenter/>
+                                </ScrollViewer>
+                            </Border>
+                        </Popup>
+                    </Grid>
+                    <ControlTemplate.Triggers>
+                        <Trigger Property="IsMouseOver" Value="True">
+                            <Setter TargetName="Chrome" Property="Background" Value="#163a6b"/>
+                        </Trigger>
+                        <Trigger Property="IsDropDownOpen" Value="True">
+                            <Setter TargetName="Chrome" Property="Background" Value="#163a6b"/>
+                        </Trigger>
+                        <Trigger Property="IsEnabled" Value="False">
+                            <Setter TargetName="Chrome" Property="Opacity" Value="0.45"/>
+                        </Trigger>
+                    </ControlTemplate.Triggers>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
+    <!-- Thin dark scrollbar -->
+    <Style x:Key="YtScrollBarPageButton" TargetType="RepeatButton">
+        <Setter Property="Focusable" Value="False"/>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="RepeatButton">
+                    <Grid Background="Transparent"/>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
+    <Style x:Key="YtScrollBarThumb" TargetType="Thumb">
+        <Setter Property="IsTabStop" Value="False"/>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="Thumb">
+                    <Border x:Name="ThumbBd" Background="#2c3c5e" CornerRadius="4" Margin="2"/>
+                    <ControlTemplate.Triggers>
+                        <Trigger Property="IsMouseOver" Value="True">
+                            <Setter TargetName="ThumbBd" Property="Background" Value="#3d5076"/>
+                        </Trigger>
+                        <Trigger Property="IsDragging" Value="True">
+                            <Setter TargetName="ThumbBd" Property="Background" Value="#4a5f8a"/>
+                        </Trigger>
+                    </ControlTemplate.Triggers>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
+    <Style TargetType="ScrollBar">
+        <Setter Property="Background" Value="Transparent"/>
+        <Setter Property="Width" Value="10"/>
+        <Setter Property="MinWidth" Value="10"/>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="ScrollBar">
+                    <Grid Background="Transparent">
+                        <Track x:Name="PART_Track" IsDirectionReversed="True">
+                            <Track.DecreaseRepeatButton>
+                                <RepeatButton Command="{x:Static ScrollBar.PageUpCommand}"
+                                              Style="{StaticResource YtScrollBarPageButton}"/>
+                            </Track.DecreaseRepeatButton>
+                            <Track.IncreaseRepeatButton>
+                                <RepeatButton Command="{x:Static ScrollBar.PageDownCommand}"
+                                              Style="{StaticResource YtScrollBarPageButton}"/>
+                            </Track.IncreaseRepeatButton>
+                            <Track.Thumb>
+                                <Thumb Style="{StaticResource YtScrollBarThumb}"/>
+                            </Track.Thumb>
+                        </Track>
+                    </Grid>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+        <Style.Triggers>
+            <Trigger Property="Orientation" Value="Horizontal">
+                <Setter Property="Width" Value="Auto"/>
+                <Setter Property="Height" Value="10"/>
+                <Setter Property="MinHeight" Value="10"/>
+            </Trigger>
+        </Style.Triggers>
+    </Style>
+
+    <!-- Slider -->
+    <Style x:Key="YtSliderTrackButton" TargetType="RepeatButton">
+        <Setter Property="Focusable" Value="False"/>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="RepeatButton">
+                    <Border Background="{Binding Tag, RelativeSource={RelativeSource TemplatedParent}}"/>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
+    <Style x:Key="YtSliderThumb" TargetType="Thumb">
+        <Setter Property="IsTabStop" Value="False"/>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="Thumb">
+                    <Ellipse x:Name="Knob" Width="16" Height="16" Fill="#e94560"
+                             Stroke="#ff8fa3" StrokeThickness="1"/>
+                    <ControlTemplate.Triggers>
+                        <Trigger Property="IsMouseOver" Value="True">
+                            <Setter TargetName="Knob" Property="Fill" Value="#ff5b78"/>
+                        </Trigger>
+                        <Trigger Property="IsDragging" Value="True">
+                            <Setter TargetName="Knob" Property="Fill" Value="#ff8fa3"/>
+                        </Trigger>
+                    </ControlTemplate.Triggers>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
+    <Style TargetType="Slider">
+        <Setter Property="Height" Value="20"/>
+        <Setter Property="VerticalAlignment" Value="Center"/>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="Slider">
+                    <Grid VerticalAlignment="Center">
+                        <Border Height="4" CornerRadius="2" Background="#2a3a5e"
+                                VerticalAlignment="Center"/>
+                        <Track x:Name="PART_Track" Height="18">
+                            <Track.DecreaseRepeatButton>
+                                <RepeatButton Command="{x:Static Slider.DecreaseLarge}"
+                                              Style="{StaticResource YtSliderTrackButton}" Tag="#e94560"/>
+                            </Track.DecreaseRepeatButton>
+                            <Track.IncreaseRepeatButton>
+                                <RepeatButton Command="{x:Static Slider.IncreaseLarge}"
+                                              Style="{StaticResource YtSliderTrackButton}" Tag="Transparent"/>
+                            </Track.IncreaseRepeatButton>
+                            <Track.Thumb>
+                                <Thumb Style="{StaticResource YtSliderThumb}"/>
+                            </Track.Thumb>
+                        </Track>
+                    </Grid>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
+    <!-- Dark tooltip -->
+    <Style TargetType="ToolTip">
+        <Setter Property="Background" Value="#1a1a2e"/>
+        <Setter Property="Foreground" Value="#e0e0e0"/>
+        <Setter Property="BorderBrush" Value="#2a3a5e"/>
+        <Setter Property="BorderThickness" Value="1"/>
+        <Setter Property="Padding" Value="8,6"/>
+        <Setter Property="FontSize" Value="12"/>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="ToolTip">
+                    <Border Background="{TemplateBinding Background}"
+                            BorderBrush="{TemplateBinding BorderBrush}"
+                            BorderThickness="{TemplateBinding BorderThickness}"
+                            CornerRadius="4" Padding="{TemplateBinding Padding}">
+                        <ContentPresenter/>
+                    </Border>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+        <Setter Property="ContentTemplate">
+            <Setter.Value>
+                <DataTemplate>
+                    <TextBlock Text="{Binding}" TextWrapping="Wrap" MaxWidth="320"
+                               Foreground="#e0e0e0" FontSize="12"/>
+                </DataTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
+    <!-- Dark context menu -->
+    <Style TargetType="ContextMenu">
+        <Setter Property="Background" Value="#16213e"/>
+        <Setter Property="Foreground" Value="#e0e0e0"/>
+        <Setter Property="BorderBrush" Value="#2a3a5e"/>
+        <Setter Property="BorderThickness" Value="1"/>
+        <Setter Property="Padding" Value="3"/>
+        <Setter Property="SnapsToDevicePixels" Value="True"/>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="ContextMenu">
+                    <Border Background="{TemplateBinding Background}"
+                            BorderBrush="{TemplateBinding BorderBrush}"
+                            BorderThickness="{TemplateBinding BorderThickness}"
+                            CornerRadius="5" Padding="{TemplateBinding Padding}">
+                        <ItemsPresenter/>
+                    </Border>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
+    <Style TargetType="MenuItem">
+        <Setter Property="Foreground" Value="#e0e0e0"/>
+        <Setter Property="Background" Value="Transparent"/>
+        <Setter Property="Padding" Value="10,6"/>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="MenuItem">
+                    <Border x:Name="Bd" Background="{TemplateBinding Background}" CornerRadius="3"
+                            Padding="{TemplateBinding Padding}" Margin="0,1">
+                        <ContentPresenter ContentSource="Header" VerticalAlignment="Center"
+                                          HorizontalAlignment="Left"/>
+                    </Border>
+                    <ControlTemplate.Triggers>
+                        <Trigger Property="IsHighlighted" Value="True">
+                            <Setter TargetName="Bd" Property="Background" Value="#26ffffff"/>
+                        </Trigger>
+                        <Trigger Property="IsEnabled" Value="False">
+                            <Setter Property="Opacity" Value="0.45"/>
+                        </Trigger>
+                    </ControlTemplate.Triggers>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
+    <!-- Menu separators render as standalone Separator controls -->
+    <Style TargetType="Separator">
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="Separator">
+                    <Border Height="1" Background="#2a3a5e" Margin="8,4"/>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
+    <!-- Dark list item (used by all list boxes) -->
+    <Style x:Key="YtListBoxItem" TargetType="ListBoxItem">
+        <Setter Property="Foreground" Value="#e0e0e0"/>
+        <Setter Property="Padding" Value="4,2"/>
+        <Setter Property="Background" Value="Transparent"/>
+        <Setter Property="HorizontalContentAlignment" Value="Left"/>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="ListBoxItem">
+                    <Border x:Name="Bd" Background="{TemplateBinding Background}"
+                            CornerRadius="3" Padding="{TemplateBinding Padding}" Margin="0,1">
+                        <ContentPresenter VerticalAlignment="Center"
+                                          HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"/>
+                    </Border>
+                    <ControlTemplate.Triggers>
+                        <Trigger Property="IsMouseOver" Value="True">
+                            <Setter TargetName="Bd" Property="Background" Value="#22ffffff"/>
+                        </Trigger>
+                        <Trigger Property="IsSelected" Value="True">
+                            <Setter TargetName="Bd" Property="Background" Value="#1a3a66"/>
+                        </Trigger>
+                    </ControlTemplate.Triggers>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
+    <Style x:Key="YtLabel" TargetType="TextBlock">
+        <Setter Property="Foreground" Value="#a0a0b0"/>
+        <Setter Property="FontSize" Value="12"/>
+    </Style>
+
+    <Style x:Key="SectionHeader" TargetType="TextBlock">
+        <Setter Property="Foreground" Value="#e0e0e0"/>
+        <Setter Property="FontSize" Value="14"/>
+        <Setter Property="FontWeight" Value="SemiBold"/>
+        <Setter Property="Margin" Value="0,0,0,8"/>
+    </Style>
+
+</ResourceDictionary>
diff --git a/Themes/index.md b/Themes/index.md
new file mode 100644
index 0000000..c0f9c40
--- /dev/null
+++ b/Themes/index.md
@@ -0,0 +1,24 @@
+# Themes — index
+
+The single source of the dark UI theme. See [`schema.md`](../schema.md) for the
+memory-map conventions.
+
+| File | Purpose |
+|------|---------|
+| `Controls.xaml` | All custom control styles/templates: `YtButton`, `YtButtonSecondary`, `IconButton`, `YtTextBox`, `YtComboBox`, scrollbar/slider/tooltip/context-menu/menu-item/separator/list-item (implicit where app-wide), `YtListBoxItem`, `YtLabel`, `SectionHeader` |
+
+How it's wired:
+- Merged once in [`App.xaml`](../App.xaml) — app-wide. New windows get the theme
+  automatically; **do not re-merge per-window**.
+- Palette: window `#1a1a2e`, fields `#0f3460`, borders `#2a3a5e`, popups
+  `#16213e`, accent `#e94560`, hover `#26ffffff`, text `#e0e0e0`.
+
+Gotchas learned the hard way:
+- `MenuItemRole` has **no `Separator` value** — separators are standalone
+  `Separator` controls with their own implicit style.
+- A custom `ComboBox` template must put the `ContentPresenter` (`SelectionBoxItem`)
+  **inside the ComboBox template, not the ToggleButton template** — the latter
+  resolves against the wrong TemplatedParent and renders nothing.
+
+Related: [`Helpers/index.md`](../Helpers/index.md) (custom controls the theme
+styles), the XAML files at repo root that consume these styles.
diff --git a/ViewModels/MainViewModel.cs b/ViewModels/MainViewModel.cs
index c90d406..f6e4e6b 100644
--- a/ViewModels/MainViewModel.cs
+++ b/ViewModels/MainViewModel.cs
@@ -255,30 +255,40 @@ public class MainViewModel : ViewModelBase
         set => SetProperty(ref _defaultStreamVisibility, value);
     }
 
-    public string[] StreamQualities { get; } = { "1080p60", "1080p30", "720p60" };
+    // ─── Resolution quality dropdown (bottom bar) ───
+    // Tiers offered to the creator before going live. First = default. The
+    // dropdown is disabled while live because YouTube stream resolution is
+    // immutable after stream creation (see TASKS.md compliance notes).
 
-    private string _streamQuality = "1080p60";
-    public string StreamQuality
+    public QualityOption[] QualityOptions { get; } =
     {
-        get => _streamQuality;
+        new("1080p60", 60, 8.0),
+        new("1080p30", 30, 8.0),
+        new("720p60", 60, 6.0),
+        new("480p30", 30, 2.5),
+    };
+
+    public string ResolutionHelp { get; } =
+        "Pick the highest resolution your upload bandwidth can comfortably sustain. " +
+        "Find your upload speed on your ISP plan or with a speed test (e.g. fast.com), " +
+        "then choose a tier your upload comfortably exceeds. 1080p60 is the default.";
+
+    private QualityOption _selectedQuality;
+    public QualityOption SelectedQuality
+    {
+        get => _selectedQuality;
         set
         {
-            if (SetProperty(ref _streamQuality, value))
+            if (SetProperty(ref _selectedQuality, value))
                 ApplyStreamQuality(value);
         }
     }
 
-    private void ApplyStreamQuality(string quality)
+    private void ApplyStreamQuality(QualityOption quality)
     {
-        var (bitrate, fps) = quality switch
-        {
-            "1080p30" => (8.0, 30.0),
-            "720p60" => (6.0, 60.0),
-            _ => (8.0, 60.0),
-        };
         var health = CurrentHealth;
-        health.CurrentBitrate = bitrate;
-        health.FPS = fps;
+        health.CurrentBitrate = quality.Bitrate;
+        health.FPS = quality.Fps;
         OnPropertyChanged(nameof(CurrentHealth));
     }
 
@@ -331,9 +341,13 @@ public class MainViewModel : ViewModelBase
 
     public MainViewModel()
     {
+        AppLog.Write("MainViewModel ctor begin");
         _youtubeAuth = new YouTubeAuthService(OAuthCredentials.ClientId, OAuthCredentials.ClientSecret);
         _youtubeStream = new YouTubeStreamService(_youtubeAuth);
         _youtubeChat = new YouTubeChatService(_youtubeAuth);
+        AppLog.Write("MainViewModel ctor: services created");
+
+        _selectedQuality = QualityOptions[0];
 
         _youtubeChat.MessageReceived += OnChatMessageReceived;
 
@@ -369,6 +383,7 @@ public class MainViewModel : ViewModelBase
         _layoutStore = new LayoutStore(DefaultLayoutPath);
         _activeLayoutPath = _layoutStore.ActivePath;
         LoadLayout();
+        AppLog.Write("MainViewModel ctor end");
     }
 
     private static string DefaultLayoutPath => Path.Combine(
@@ -381,6 +396,7 @@ public class MainViewModel : ViewModelBase
         _isLoading = true;
         try
         {
+            AppLog.Write("LoadLayout begin");
             var scenes = _layoutStore.Load();
             Scenes.Clear();
             foreach (var scene in scenes)
@@ -394,6 +410,7 @@ public class MainViewModel : ViewModelBase
                 AddScene("Chat", isChatScene: true);
                 AddScene("Ending");
             }
+            AppLog.Write($"LoadLayout: {Scenes.Count} scenes loaded");
         }
         finally
         {
@@ -402,6 +419,7 @@ public class MainViewModel : ViewModelBase
         ActiveScene = Scenes.FirstOrDefault();
         UpdateActiveBackground();
         ScheduleSave();
+        AppLog.Write("LoadLayout end");
     }
 
     public void Shutdown()
diff --git a/ViewModels/index.md b/ViewModels/index.md
new file mode 100644
index 0000000..56f106b
--- /dev/null
+++ b/ViewModels/index.md
@@ -0,0 +1,12 @@
+# ViewModels — index
+
+MVVM layer. See [`schema.md`](../schema.md) for the memory-map conventions.
+
+| File | Purpose |
+|------|---------|
+| `MainViewModel.cs` | The app brain: scenes/sources collections + commands, stream state (`IsLive`/`IsOffline`/`IsConnected`), chat feed, overlays, layout save/open, **resolution dropdown** (`QualityOptions`, `SelectedQuality`, `ResolutionHelp`, `ApplyStreamQuality`) |
+| `GoLiveViewModel.cs` | Start Stream dialog: title/description/visibility, start/cancel requests |
+| `ReuseImageViewModel.cs` | Add Image dialog: candidate list (`ReuseImageCandidate`), reuse/new/cancel |
+
+Related: [`Models/index.md`](../Models/index.md) for the data; [`Services/index.md`](../Services/index.md)
+for what the ViewModels drive; base class in [`Helpers/ViewModelBase.cs`](../Helpers/ViewModelBase.cs).
diff --git a/ai.md b/ai.md
index b936fee..4a2d523 100644
--- a/ai.md
+++ b/ai.md
@@ -1,5 +1,9 @@
 # ytLlive — AI Guide
 
+> Memory map entry point. Conventions live in [`schema.md`](schema.md); task
+> status and YouTube API research in [`TASKS.md`](TASKS.md); directory maps in
+> each folder's `index.md`. Reading order: this file → `TASKS.md` → `<dir>/index.md` → source.
+
 ## Run
 
 ```bash
@@ -19,10 +23,11 @@ C# / WPF (.NET 8) following MVVM:
 
 | Path | Role |
 |------|------|
-| `Models/` | Plain data types — Scene, Source, StreamConfig, StreamHealth, YouTubeChannel, ChatMessage |
-| `ViewModels/` | MainViewModel — exposes collections + commands for the UI |
+| `Models/` | Plain data types — Scene, Source, QualityOption, StreamConfig, StreamHealth, YouTubeChannel, ChatMessage |
+| `ViewModels/` | MainViewModel — exposes collections + commands for the UI; GoLiveViewModel, ReuseImageViewModel |
 | `Services/` | YouTube OAuth2, stream/broadcast management, live chat polling, LayoutStore (SQLite) |
-| `Helpers/` | ViewModelBase (INotifyPropertyChanged), RelayCommand, ImageCache |
+| `Helpers/` | ViewModelBase (INotifyPropertyChanged), RelayCommand, ImageCache, AppLog (file logger), FocusPreservingListBox, OAuthCredentials, visibility converters |
+| `Themes/` | `Controls.xaml` — the single dark-theme source, merged once in `App.xaml` (see `Themes/index.md`) |
 | `MainWindow.xaml` | Dark theme; layout: top bar (controls), center (preview), left (scenes/sources), right (chat), bottom (health) |
 
 ### Key patterns
@@ -32,16 +37,18 @@ C# / WPF (.NET 8) following MVVM:
 - ViewModels are constructed in XAML (`<vm:MainViewModel/>` as DataContext)
 - Services are currently instantiated in MainViewModel's constructor — no DI container yet
 - Layout persists to SQLite (`Microsoft.Data.Sqlite`); scenes/sources/asset bytes stored in the DB, asset identity is a SHA-256 content hash (1:M reuse, no file paths — assets are always available)
+- Theming: all custom styles live in `Themes/Controls.xaml`, merged in `App.xaml` — never duplicate styles per-window (dialog duplicates were consolidated into this dictionary)
+- Resolution tiers (bottom bar): 1080p60@8 → 1080p30@8 → 720p60@6 → 480p30@2.5 Mbps; default = first. A **tooltip** explains finding upload bandwidth — an in-app speed test was deliberately dropped (unreliable)
+- Crash diagnosis: `AppLog` writes startup checkpoints to `%APPDATA%\ytLlive\startup.log`; `App.xaml.cs` logs `DispatcherUnhandledException`/`AppDomain.UnhandledException`. When WPF won't run from WSL, this log is how you find the failure (it caught the `MenuItemRole.Separator` XAML crash and the ComboBox SelectionBoxItem bug)
 
 ### Current limitations / TODOs
 
-- `OAuthCredentials.ClientId` / `ClientSecret` in `Helpers/OAuthCredentials.cs` are empty — the app
-  owner fills them in once (developer task, baked into the binary; creators never configure anything)
+- `Helpers/OAuthCredentials.cs` now contains the real ClientId/ClientSecret — auth service is implemented, but **tokens still don't persist** (Windows DPAPI planned; account UI in the GoLive dialog is simulated)
 - `GoLiveViewModel.SignIn`/`ChangeAccount` removed — Connect (OAuth) is the only entry to streaming
-- No token persistence yet (Windows DPAPI planned) — scene/source/asset layout *does* persist (SQLite)
+- Scene/source/asset layout *does* persist (SQLite); token persistence does not (yet)
 - `YouTubeStreamService` uses hardcoded `1080p`/`60fps` and per-broadcast streams — must switch to the v3 `variable` reusable stream
 - No capture/encoding/RTMP yet
-- Stream config (title/description/visibility/quality) still in-memory
+- `StreamConfig` defaults (`TargetBitrate=6000`, `Resolution="1920x1080"`) are stale — the live dropdown drives `StreamHealth.CurrentBitrate`/`FPS` instead
 
 ## Design Principle
 
diff --git a/schema.md b/schema.md
new file mode 100644
index 0000000..3af47e3
--- /dev/null
+++ b/schema.md
@@ -0,0 +1,54 @@
+# ytLlive — Memory Map (schema)
+
+This file defines how the repo stores durable, associative memory: context as
+plain markdown files, versioned in git. It is the map of the map — the schema
+that every other memory file follows. Read `ai.md` first; this file explains
+*why* and *how*.
+
+## Why markdown files, not a database
+
+- Grep-able, diffable, portable, human-editable — no tooling lock-in.
+- Git gives versioning and history for free; every stale fact is a `git log` away.
+- Files form a graph: each file is a node, each relative link an edge. The map
+  stays associative (like memory) rather than a rigid tree.
+
+## File inventory
+
+| File | Role | Entry point? |
+|------|------|--------------|
+| `README.md` | Human-facing intro: what the app is, how to run it, roadmap | no |
+| `ai.md` | **AI guide + session handoff** — architecture, patterns, decisions, the cognitive map home | **yes — start here** |
+| `TASKS.md` | Task queue + authoritative YouTube API research facts + task statuses | yes — for status |
+| `schema.md` | This file: the conventions below | when in doubt |
+| `<dir>/index.md` | Per-directory map (progressive disclosure): what lives there + links | when diving into code |
+| `Views/` | Reserved for Views; currently empty | — |
+
+## Conventions
+
+1. **Semantic filenames.** A file's name says what it is (`YouTubeAuthService.cs`,
+   `FocusPreservingListBox.cs`). No codes, no abbreviations. Naming beats search.
+2. **One `index.md` per code directory.** The index is a Map of Content (MOC):
+   it lists every file in that directory with a one-line purpose and links out to
+   related directories. Details live in the files, never duplicated in the index.
+3. **Links over hierarchy.** Prefer relative links between related files over
+   deep nesting. Relationships that matter should be visible from `ai.md` or an
+   `index.md`; a note that is unreachable from `ai.md` might as well not exist.
+4. **Stale facts get FIXED, not appended.** A wrong map is worse than no map.
+   When the code changes, update the memory file in the same change — no
+   "TODO: update later" notes.
+5. **Progressive disclosure.** Don't cram detail into `ai.md`. `ai.md` names
+   concepts and points at files; the indexes and source are the detail. Each
+   layer adds resolution only when you drill in.
+
+## Reading order
+
+1. `ai.md` — what this app is, how it's built, current state, open decisions.
+2. `TASKS.md` — what's done, what's next, and the YouTube API constraints.
+3. `<dir>/index.md` — to understand a directory before reading its files.
+4. The source files themselves — always the authority over any memory file.
+
+## Integration rule
+
+Every feature change ships with its memory update: `ai.md` for architecture /
+patterns, `TASKS.md` for status, index files when the layout changes. That is
+what keeps the map accurate enough to trust next session.