diff --git a/src/TextForge.Core/Engine/DocumentEngine.cs b/src/TextForge.Core/Engine/DocumentEngine.cs
index 9285337..4b67577 100644
--- a/src/TextForge.Core/Engine/DocumentEngine.cs
+++ b/src/TextForge.Core/Engine/DocumentEngine.cs
@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using TextForge.Core.Documents;
 using TextForge.Core.Modules;
 using TextForge.Core.Templates;
@@ -9,6 +6,8 @@ namespace TextForge.Core.Engine;
 
 public class DocumentEngine : IDocumentEngine
 {
+    private readonly DefaultTemplate _defaultTemplate = new();
+
     public RenderTree Evaluate(Document document, DefaultTemplate template)
     {
         ArgumentNullException.ThrowIfNull(document);
diff --git a/src/TextForge.Core/Templates/DefaultTemblate.cs b/src/TextForge.Core/Templates/DefaultTemblate.cs
index 9eb2e64..917be84 100644
--- a/src/TextForge.Core/Templates/DefaultTemblate.cs
+++ b/src/TextForge.Core/Templates/DefaultTemblate.cs
@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using TextForge.Core.Engine;
 using TextForge.Core.Modules;
@@ -8,10 +9,13 @@ public class DefaultTemplate
 {
     public string Name { get; init; } = "Default";
 
+    /// <summary>
+    /// Global template baseline defaults. Default text color is standard blue.
+    /// </summary>
     public ModuleFeatures DocumentDefaults { get; init; } = new()
     {
         Font = "Segoe UI",
-        Color = "#1F2937",
+        Color = "#2563EB", // Standard Template Blue
         FontWeight = ModuleFontWeight.Normal,
         LineSpacing = 1.2
     };
@@ -71,7 +75,7 @@ public class DefaultTemplate
         }
     };
 
-    public Dictionary<string, ModuleFeatures> NamedStyles { get; init; } = new()
+    public Dictionary<string, ModuleFeatures> NamedStyles { get; init; } = new(StringComparer.OrdinalIgnoreCase)
     {
         ["Title"] = new ModuleFeatures
         {
@@ -95,7 +99,7 @@ public class DefaultTemplate
         }
     };
 
-    public Dictionary<string, LayoutProperties> NamedLayoutStyles { get; init; } = new()
+    public Dictionary<string, LayoutProperties> NamedLayoutStyles { get; init; } = new(StringComparer.OrdinalIgnoreCase)
     {
         ["Title"] = new LayoutProperties
         {
@@ -120,6 +124,8 @@ public class DefaultTemplate
 
     public ModuleFeatures ResolveFeatures(Module module)
     {
+        ArgumentNullException.ThrowIfNull(module);
+
         var resolved = DocumentDefaults;
 
         if (TypeDefaults.TryGetValue(module.Type, out var typeStyle))
@@ -127,7 +133,8 @@ public ModuleFeatures ResolveFeatures(Module module)
             resolved = typeStyle.MergeWith(resolved);
         }
 
-        if (module.StyleKey is not null && NamedStyles.TryGetValue(module.StyleKey, out var namedStyle))
+        var key = module.StyleKey ?? module.Name;
+        if (!string.IsNullOrWhiteSpace(key) && NamedStyles.TryGetValue(key, out var namedStyle))
         {
             resolved = namedStyle.MergeWith(resolved);
         }
@@ -137,6 +144,8 @@ public ModuleFeatures ResolveFeatures(Module module)
 
     public LayoutProperties ResolveLayout(Module module)
     {
+        ArgumentNullException.ThrowIfNull(module);
+
         var resolved = DocumentLayoutDefaults;
 
         if (TypeLayoutDefaults.TryGetValue(module.Type, out var typeLayout))
@@ -144,7 +153,8 @@ public LayoutProperties ResolveLayout(Module module)
             resolved = typeLayout.MergeWith(resolved);
         }
 
-        if (module.StyleKey is not null && NamedLayoutStyles.TryGetValue(module.StyleKey, out var namedLayout))
+        var key = module.StyleKey ?? module.Name;
+        if (!string.IsNullOrWhiteSpace(key) && NamedLayoutStyles.TryGetValue(key, out var namedLayout))
         {
             resolved = namedLayout.MergeWith(resolved);
         }
diff --git a/src/TextForge.Desktop/Views/Components/ModuleEditorView.axaml.cs b/src/TextForge.Desktop/Views/Components/ModuleEditorView.axaml.cs
index 5fad44b..b378ecd 100644
--- a/src/TextForge.Desktop/Views/Components/ModuleEditorView.axaml.cs
+++ b/src/TextForge.Desktop/Views/Components/ModuleEditorView.axaml.cs
@@ -1,12 +1,14 @@
 using System;
 using Avalonia.Controls;
 using Avalonia.Interactivity;
+using TextForge.Core.Documents;
 using TextForge.Core.Modules;
 
 namespace TextForge.Desktop.Views.Components;
 
 public partial class ModuleEditorView : UserControl
 {
+    private Document? _document;
     public event EventHandler<Module>? ModuleMoveUpRequested;
     public event EventHandler<Module>? ModuleMoveDownRequested;
     public event EventHandler<Module>? ModuleDeleteRequested;
@@ -39,4 +41,18 @@ private void DeleteModuleButton_Click(object? sender, RoutedEventArgs e)
             ModuleDeleteRequested?.Invoke(this, module);
         }
     }
+    /// <summary>
+    /// Binds the editor to a document instance.
+    /// Done once per document load.
+    /// </summary>
+    public void SetDocument(Document document)
+    {
+        if (_document == document) return;
+
+        _document = document;
+
+        // Assign the collection directly ONCE.
+        // ObservableCollection will handle all subsequent Add/Remove operations automatically.
+        ModuleListBox.ItemsSource = _document.Modules;
+    }
 }
diff --git a/tests/TextForge.Tests/DefaultTemplateTests.cs b/tests/TextForge.Tests/DefaultTemplateTests.cs
index 8c74e2a..dd58ee4 100644
--- a/tests/TextForge.Tests/DefaultTemplateTests.cs
+++ b/tests/TextForge.Tests/DefaultTemplateTests.cs
@@ -19,7 +19,7 @@ public void ResolveFeatures_StandardTextModule_InheritsDocumentAndTypeDefaults()
 
         // Assert: gets baseline font and color from document defaults + type line spacing
         Assert.Equal("Segoe UI", features.Font);
-        Assert.Equal("#1F2937", features.Color);
+        Assert.Equal("#2563EB", features.Color);
         Assert.Equal(ModuleFontWeight.Normal, features.FontWeight);
         Assert.Equal(1.2, features.LineSpacing);
         Assert.False(features.Italic);
diff --git a/tests/TextForge.Tests/TemplateResolutionTests.cs b/tests/TextForge.Tests/TemplateResolutionTests.cs
new file mode 100644
index 0000000..1f02c9f
--- /dev/null
+++ b/tests/TextForge.Tests/TemplateResolutionTests.cs
@@ -0,0 +1,62 @@
+using Xunit;
+using TextForge.Core.Documents;
+using TextForge.Core.Engine;
+using TextForge.Core.Modules;
+using TextForge.Core.Templates;
+
+namespace TextForge.Tests;
+
+public class TemplateResolutionTests
+{
+    private readonly DocumentEngine _engine = new();
+    private readonly DefaultTemplate _template = new();
+
+    [Fact]
+    public void Evaluate_DefaultDocument_AppliesTemplateBaselineBlueColor()
+    {
+        // Arrange
+        var doc = new Document("Test Showcase");
+        doc.AddModule(Module.CreateTitle("Welcome to TextForge"));
+        doc.AddModule(Module.CreateParagraph("Standard text body."));
+
+        // Act
+        var renderTree = _engine.Evaluate(doc, _template);
+
+        // Assert
+        Assert.Equal(2, renderTree.RootNodes.Count);
+        Assert.Equal("#2563EB", renderTree.RootNodes[0].Features.Color);
+        Assert.Equal("#2563EB", renderTree.RootNodes[1].Features.Color);
+    }
+
+    [Fact]
+    public void Evaluate_ModuleExplicitColorOverride_TakesPrecedenceOverTemplate()
+    {
+        // Arrange
+        var doc = new Document("Alert Test");
+        var alertModule = Module.CreateAlert("Warning Message", color: "#DC2626");
+        doc.AddModule(alertModule);
+
+        // Act
+        var renderTree = _engine.Evaluate(doc, _template);
+
+        // Assert
+        Assert.Single(renderTree.RootNodes);
+        Assert.Equal("#DC2626", renderTree.RootNodes[0].Features.Color);
+    }
+
+    [Fact]
+    public void Evaluate_UnknownOrCustomModule_FallsBackSafelyToBaselineColor()
+    {
+        // Arrange
+        var doc = new Document("Fallback Test");
+        var unknownModule = new Module("Custom content", ModuleType.Custom, name: "unsupported-custom-archetype");
+        doc.AddModule(unknownModule);
+
+        // Act
+        var renderTree = _engine.Evaluate(doc, _template);
+
+        // Assert
+        Assert.Single(renderTree.RootNodes);
+        Assert.Equal("#2563EB", renderTree.RootNodes[0].Features.Color);
+    }
+}