diff --git a/Yafc.Model/Data/DataClasses.cs b/Yafc.Model/Data/DataClasses.cs
index e634d88e..14069ae8 100644
--- a/Yafc.Model/Data/DataClasses.cs
+++ b/Yafc.Model/Data/DataClasses.cs
@@ -5,7 +5,6 @@
 using System.Linq;
 using System.Runtime.CompilerServices;
 using Yafc.I18n;
-using Yafc.UI;
 [assembly: InternalsVisibleTo("Yafc.Parser")]
 
 namespace Yafc.Model;
@@ -39,7 +38,12 @@ public abstract class FactorioObject : IFactorioObjectWrapper, IComparable<Facto
     public string locName { get; internal set; } = null!; // null-forgiving: Copied from name if still null at the end of CalculateMaps
     public string? locDescr { get; internal set; }
     internal FactorioIconPart[]? iconSpec { get; set; }
-    public Icon icon { get; internal set; }
+    /// <summary>
+    /// Integer icon handle assigned during data loading.
+    /// This value matches the numeric value of <c>Yafc.UI.Icon</c>
+    /// and should only be interpreted in the UI layer via <c>GetIcon()</c>.
+    /// </summary>
+    public int iconId { get; internal set; }
     public FactorioId id { get; internal set; }
     internal abstract FactorioObjectSortOrder sortingOrder { get; }
     public FactorioObjectSpecialType specialType { get; internal set; }
diff --git a/Yafc.Model/Data/DataUtils.cs b/Yafc.Model/Data/DataUtils.cs
index dc5d9f8d..c0167af9 100644
--- a/Yafc.Model/Data/DataUtils.cs
+++ b/Yafc.Model/Data/DataUtils.cs
@@ -128,9 +128,6 @@ public int Compare(T? x, T? y) {
     /// but will appear as only producing U-235 and consuming U-238 when <see langword="true"/>.
     /// </summary>
     public static bool netProduction { get; internal set; }
-    public static Icon NoFuelIcon { get; internal set; }
-    public static Icon WarningIcon { get; internal set; }
-    public static Icon HandIcon { get; internal set; }
 
     public static readonly Random random = new Random();
 
diff --git a/Yafc.Model/Model/ProductionSummary.cs b/Yafc.Model/Model/ProductionSummary.cs
index 97d4cdd6..1ea073ad 100644
--- a/Yafc.Model/Model/ProductionSummary.cs
+++ b/Yafc.Model/Model/ProductionSummary.cs
@@ -54,19 +54,10 @@ protected internal override void AfterDeserialize() {
     [SkipSerialization] public Dictionary<IObjectWithQuality<Goods>, float> flow { get; } = [];
     private bool needRefreshFlow = true;
 
-    public Icon icon {
-        get {
-            if (subgroup != null) {
-                return Icon.Folder;
-            }
-
-            if (page?.page == null) {
-                return Icon.Warning;
-            }
-
-            return page.page.icon?.icon ?? Icon.None;
-        }
-    }
+    /// <summary>True when this entry represents a folder/subgroup rather than a project page.</summary>
+    public bool IsSubgroup => subgroup != null;
+    /// <summary>True when this entry's referenced page has been removed or could not be found.</summary>
+    public bool IsMissingPage => !IsSubgroup && page?.page == null;
 
     public string name {
         get {
diff --git a/Yafc.Parser/Data/FactorioDataDeserializer.cs b/Yafc.Parser/Data/FactorioDataDeserializer.cs
index c463d63a..d0ac4dec 100644
--- a/Yafc.Parser/Data/FactorioDataDeserializer.cs
+++ b/Yafc.Parser/Data/FactorioDataDeserializer.cs
@@ -230,9 +230,10 @@ private void RenderIcons() {
                 cache[(".", digit.ToString())] = SDL_image.IMG_Load("Data/Digits/" + digit + ".png");
             }
 
-            DataUtils.NoFuelIcon = CreateSimpleIcon(cache, "fuel-icon-red");
-            DataUtils.WarningIcon = CreateSimpleIcon(cache, "warning-icon");
-            DataUtils.HandIcon = CreateSimpleIcon(cache, "hand");
+            SystemIcons.Initialize(
+                noFuelIcon: CreateSimpleIcon(cache, "fuel-icon-red"),
+                warningIcon: CreateSimpleIcon(cache, "warning-icon"),
+                handIcon: CreateSimpleIcon(cache, "hand"));
 
             Dictionary<string, Icon> simpleSpritesCache = [];
             int rendered = 0;
@@ -246,15 +247,15 @@ private void RenderIcons() {
                     bool simpleSprite = o.iconSpec.Length == 1 && o.iconSpec[0].IsSimple();
 
                     if (simpleSprite && simpleSpritesCache.TryGetValue(o.iconSpec[0].path, out var icon)) {
-                        o.icon = icon;
+                        o.iconId = (int)icon;
                         continue;
                     }
 
                     try {
-                        o.icon = CreateIconFromSpec(cache, o.iconSpec);
+                        o.iconId = (int)CreateIconFromSpec(cache, o.iconSpec);
 
                         if (simpleSprite) {
-                            simpleSpritesCache[o.iconSpec[0].path] = o.icon;
+                            simpleSpritesCache[o.iconSpec[0].path] = (Icon)o.iconId;
                         }
                     }
                     catch (Exception ex) {
@@ -262,7 +263,7 @@ private void RenderIcons() {
                     }
                 }
                 else if (o is Recipe recipe && recipe.mainProduct != null) {
-                    o.icon = recipe.mainProduct.icon;
+                    o.iconId = recipe.mainProduct.iconId;
                 }
             }
         }
diff --git a/Yafc.UI/Core/SystemIcons.cs b/Yafc.UI/Core/SystemIcons.cs
new file mode 100644
index 00000000..9dca5dd5
--- /dev/null
+++ b/Yafc.UI/Core/SystemIcons.cs
@@ -0,0 +1,33 @@
+namespace Yafc.UI;
+
+/// <summary>
+/// Holds the set of game-sourced system icons (e.g. fuel, warning, hand) that are
+/// rendered from Factorio's own sprite files during the data loading phase.
+/// These are distinct from the built-in YAFC vector icons defined in <see cref="Icon"/>.
+/// </summary>
+public static class SystemIcons {
+    /// <summary>
+    /// The icon used to indicate a missing or invalid fuel source.
+    /// Set during data loading; no UI consumer yet (pre-existing).
+    /// </summary>
+    public static Icon NoFuelIcon { get; private set; }
+
+    /// <summary>
+    /// The icon used to display a general warning.
+    /// Set during data loading; no UI consumer yet (pre-existing).
+    /// </summary>
+    public static Icon WarningIcon { get; private set; }
+
+    /// <summary>The hand/grab icon used to mark certain special goods (e.g. void energy).</summary>
+    public static Icon HandIcon { get; private set; }
+
+    /// <summary>
+    /// Initializes the set of game-sourced system icons after they are rendered from Factorio assets.
+    /// </summary>
+    public static void Initialize(Icon noFuelIcon, Icon warningIcon, Icon handIcon) {
+        NoFuelIcon = noFuelIcon;
+        WarningIcon = warningIcon;
+        HandIcon = handIcon;
+    }
+}
+
diff --git a/Yafc/Widgets/FactorioObjectIconExtensions.cs b/Yafc/Widgets/FactorioObjectIconExtensions.cs
new file mode 100644
index 00000000..6d597bfc
--- /dev/null
+++ b/Yafc/Widgets/FactorioObjectIconExtensions.cs
@@ -0,0 +1,19 @@
+using Yafc.Model;
+using Yafc.UI;
+
+namespace Yafc;
+
+/// <summary>
+/// Extension methods that bridge domain objects (<see cref="FactorioObject"/>) to their
+/// UI representation (<see cref="Icon"/>), keeping the domain layer free of UI concerns.
+/// This bridge currently lives in the app layer because <c>Yafc.UI</c> does not reference
+/// <c>Yafc.Model</c>; move it once dependency boundaries are reworked.
+/// </summary>
+public static class FactorioObjectIconExtensions {
+    /// <summary>
+    /// Returns the <see cref="Icon"/> value associated with this <see cref="FactorioObject"/>.
+    /// The domain object stores this as an integer handle (<see cref="FactorioObject.iconId"/>);
+    /// this method converts it to the <see cref="Icon"/> enum for rendering.
+    /// </summary>
+    public static Icon GetIcon(this FactorioObject obj) => (Icon)obj.iconId;
+}
diff --git a/Yafc/Widgets/ImmediateWidgets.cs b/Yafc/Widgets/ImmediateWidgets.cs
index b0f6f8c7..7240eb19 100644
--- a/Yafc/Widgets/ImmediateWidgets.cs
+++ b/Yafc/Widgets/ImmediateWidgets.cs
@@ -72,10 +72,10 @@ public static void BuildFactorioObjectIcon(this ImGui gui, IFactorioObjectWrappe
         SchemeColor color = (obj.target.IsAccessible() || displayStyle.AlwaysAccessible) ? SchemeColor.Source : SchemeColor.SourceFaint;
         if (displayStyle.UseScaleSetting) {
             Rect rect = gui.AllocateRect(displayStyle.Size, displayStyle.Size, RectAlignment.Middle);
-            gui.DrawIcon(rect.Expand(displayStyle.Size * (Project.current.preferences.iconScale - 1) / 2), obj.target.icon, color);
+            gui.DrawIcon(rect.Expand(displayStyle.Size * (Project.current.preferences.iconScale - 1) / 2), obj.target.GetIcon(), color);
         }
         else {
-            gui.BuildIcon(obj.target.icon, displayStyle.Size, color);
+            gui.BuildIcon(obj.target.GetIcon(), displayStyle.Size, color);
         }
         if (gui.isBuilding && displayStyle.MilestoneDisplay != MilestoneDisplay.None
             && (obj.target.IsAccessible() || Project.current.preferences.showMilestoneOnInaccessible)) {
@@ -86,7 +86,7 @@ public static void BuildFactorioObjectIcon(this ImGui gui, IFactorioObjectWrappe
                 Vector2 size = new Vector2(displayStyle.Size / 2f);
                 var delta = contain ? size : size / 2f;
                 Rect milestoneIcon = new Rect(gui.lastRect.BottomRight - delta, size);
-                var icon = milestone == Database.voidEnergy.target ? DataUtils.HandIcon : milestone.icon;
+                var icon = milestone == Database.voidEnergy.target ? SystemIcons.HandIcon : milestone.GetIcon();
                 gui.DrawIcon(milestoneIcon, icon, color);
             }
         }
@@ -97,7 +97,7 @@ public static void BuildFactorioObjectIcon(this ImGui gui, IFactorioObjectWrappe
             Vector2 delta = new(0, size.Y);
             Rect qualityRect = new Rect(gui.lastRect.BottomLeft - delta, size);
 
-            gui.DrawIcon(qualityRect, quality.icon, SchemeColor.Source);
+            gui.DrawIcon(qualityRect, quality.GetIcon(), SchemeColor.Source);
         }
         if (gui.isBuilding && obj.target is Item { baseSpoilTime: > 0 } or Entity { baseSpoilTime: > 0 }) {
             Vector2 size = new Vector2(displayStyle.Size / 2.5f);
diff --git a/Yafc/Widgets/MainScreenTabBar.cs b/Yafc/Widgets/MainScreenTabBar.cs
index 380d7421..3ac7bbbf 100644
--- a/Yafc/Widgets/MainScreenTabBar.cs
+++ b/Yafc/Widgets/MainScreenTabBar.cs
@@ -41,7 +41,7 @@ private void BuildContents(ImGui gui) {
             using (gui.EnterGroup(new Padding(0.5f, 0.2f, 0.2f, 0.5f))) {
                 gui.spacing = 0.2f;
                 if (page.icon != null) {
-                    gui.BuildIcon(page.icon.icon);
+                    gui.BuildIcon(page.icon.GetIcon());
                 }
                 else {
                     _ = gui.AllocateRect(0f, 1.5f);
diff --git a/Yafc/Widgets/ObjectTooltip.cs b/Yafc/Widgets/ObjectTooltip.cs
index dd9f2c1a..188a2bb9 100644
--- a/Yafc/Widgets/ObjectTooltip.cs
+++ b/Yafc/Widgets/ObjectTooltip.cs
@@ -72,7 +72,7 @@ private void BuildHeader(ImGui gui) {
                                 goto doneDrawing;
                             }
                             if (milestoneMask[maskBit]) {
-                                gui.BuildIcon(milestones.Current.icon, 1f, SchemeColor.Source);
+                                gui.BuildIcon(milestones.Current.GetIcon(), 1f, SchemeColor.Source);
                                 j++;
                             }
 
diff --git a/Yafc/Windows/MainScreen.cs b/Yafc/Windows/MainScreen.cs
index e40cde84..0fafd33d 100644
--- a/Yafc/Windows/MainScreen.cs
+++ b/Yafc/Windows/MainScreen.cs
@@ -119,7 +119,7 @@ private void ReRunAnalysis() {
     private void BuildPage(ImGui gui, ProjectPage element, int index) {
         using (gui.EnterGroup(new Padding(1f, 0.25f), RectAllocator.LeftRow)) {
             if (element.icon != null) {
-                gui.BuildIcon(element.icon.icon);
+                gui.BuildIcon(element.icon.GetIcon());
             }
 
             gui.RemainingRow().BuildText(element.name, TextBlockDisplayStyle.Default(element.visible ? SchemeColor.BackgroundText : SchemeColor.BackgroundTextFaint));
@@ -301,7 +301,7 @@ private void BuildPage(ImGui gui) {
         else {
             if (gui.isBuilding && Database.objectsByTypeName.TryGetValue("Entity.compilatron", out var compilatron)) {
                 gui.AllocateSpacing((pageVisibleSize.Y - 3f) / 2);
-                gui.BuildIcon(compilatron.icon, 3f);
+                gui.BuildIcon(compilatron.GetIcon(), 3f);
             }
         }
     }
diff --git a/Yafc/Workspace/ProductionSummary/ProductionSummaryView.cs b/Yafc/Workspace/ProductionSummary/ProductionSummaryView.cs
index bc50311d..26e20090 100644
--- a/Yafc/Workspace/ProductionSummary/ProductionSummaryView.cs
+++ b/Yafc/Workspace/ProductionSummary/ProductionSummaryView.cs
@@ -30,9 +30,10 @@ public override void BuildHeader(ImGui gui) { }
         public override void BuildElement(ImGui gui, ProductionSummaryEntry row) {
             gui.allocator = RectAllocator.Center;
             gui.spacing = 0f;
-            if (row.subgroup != null) {
-                if (gui.BuildButton(row.subgroup.expanded ? Icon.ChevronDown : Icon.ChevronRight)) {
-                    row.subgroup.RecordChange().expanded = !row.subgroup.expanded;
+            if (row.IsSubgroup) {
+                var subgroup = row.subgroup!; // IsSubgroup guarantees subgroup != null
+                if (gui.BuildButton(subgroup.expanded ? Icon.ChevronDown : Icon.ChevronRight)) {
+                    subgroup.RecordChange().expanded = !subgroup.expanded;
                     view.flatHierarchy.SetData(view.model.group);
                 }
             }
@@ -75,21 +76,22 @@ private GuiBuilder AddProductionTableDropdown(SearchableList<ProjectPage> pagesD
         public override void BuildElement(ImGui gui, ProductionSummaryEntry entry) {
             gui.allocator = RectAllocator.LeftAlign;
 
-            if (entry.subgroup != null) {
-                if (entry.subgroup.expanded) {
-                    BuildButtons(gui, 1.5f, entry.subgroup);
+            if (entry.IsSubgroup) {
+                var subgroup = entry.subgroup!; // IsSubgroup guarantees subgroup != null
+                if (subgroup.expanded) {
+                    BuildButtons(gui, 1.5f, subgroup);
                 }
                 else {
-                    if (gui.BuildTextInput(entry.subgroup.name, out string newText, LSs.LegacySummaryGroupNameHint, delayed: true)) {
-                        entry.subgroup.RecordUndo().name = newText;
+                    if (gui.BuildTextInput(subgroup.name, out string newText, LSs.LegacySummaryGroupNameHint, delayed: true)) {
+                        subgroup.RecordUndo().name = newText;
                     }
                 }
             }
             else if (entry.page != null) { // The constructor should have thrown if this check fails, but it helps the nullability analysis
                 using (gui.EnterGroup(new Padding(0.3f), RectAllocator.LeftRow, SchemeColor.None, 0.2f)) {
-                    var icon = entry.icon;
+                    Icon icon = entry.IsMissingPage ? Icon.Warning : entry.page.page!.icon?.GetIcon() ?? Icon.None;
                     if (icon != Icon.None) {
-                        gui.BuildIcon(entry.icon);
+                        gui.BuildIcon(icon);
                     }
 
                     gui.BuildText(entry.name);
@@ -129,7 +131,7 @@ public override void BuildElement(ImGui gui, ProductionSummaryEntry entry) {
         private static VirtualScrollList<ProjectPage>.Drawer PagesDropdownDrawer(ProductionSummaryGroup group) => (gui, element, _) => {
             using (gui.EnterGroup(new Padding(1f, 0.25f), RectAllocator.LeftRow)) {
                 if (element.icon != null) {
-                    gui.BuildIcon(element.icon.icon);
+                    gui.BuildIcon(element.icon.GetIcon());
                 }
 
                 gui.RemainingRow().BuildText(element.name, TextBlockDisplayStyle.Default(element.visible ? SchemeColor.BackgroundText : SchemeColor.BackgroundTextFaint));
@@ -189,7 +191,7 @@ public override void BuildElement(ImGui gui, ProductionSummaryEntry data) {
 
                 if (!view.model.columnsExist.Contains(goods)) {
                     grid.Next();
-                    var evt = gui.BuildButton(goods.target.icon, amount > 0f ? SchemeColor.Green : SchemeColor.None, size: 1.5f);
+                    var evt = gui.BuildButton(goods.target.GetIcon(), amount > 0f ? SchemeColor.Green : SchemeColor.None, size: 1.5f);
                     if (evt == ButtonEvent.Click) {
                         view.AddOrRemoveColumn(goods);
                     }
diff --git a/Yafc/Workspace/ProductionTable/ModuleFillerParametersScreen.cs b/Yafc/Workspace/ProductionTable/ModuleFillerParametersScreen.cs
index 11c25f6a..4b36611a 100644
--- a/Yafc/Workspace/ProductionTable/ModuleFillerParametersScreen.cs
+++ b/Yafc/Workspace/ProductionTable/ModuleFillerParametersScreen.cs
@@ -41,8 +41,8 @@ private void ListDrawer(ImGui gui, KeyValuePair<EntityCrafter, BeaconOverrideCon
                     }
                 }
             });
-        gui.DrawIcon(new(gui.lastRect.X, gui.lastRect.Y, 1.25f, 1.25f), config.beacon.target.icon, SchemeColor.Source);
-        gui.DrawIcon(new(gui.lastRect.TopRight - new Vector2(1.25f, 0), new Vector2(1.25f, 1.25f)), config.beaconModule.target.icon, SchemeColor.Source);
+        gui.DrawIcon(new(gui.lastRect.X, gui.lastRect.Y, 1.25f, 1.25f), config.beacon.target.GetIcon(), SchemeColor.Source);
+        gui.DrawIcon(new(gui.lastRect.TopRight - new Vector2(1.25f, 0), new Vector2(1.25f, 1.25f)), config.beaconModule.target.GetIcon(), SchemeColor.Source);
         switch (click) {
             case GoodsWithAmountEvent.LeftButtonClick:
                 SelectSingleObjectPanel.SelectQualityWithNone(Database.usableBeacons,
diff --git a/Yafc/Workspace/ProductionTable/ProductionTableView.cs b/Yafc/Workspace/ProductionTable/ProductionTableView.cs
index e8a60eee..77760078 100644
--- a/Yafc/Workspace/ProductionTable/ProductionTableView.cs
+++ b/Yafc/Workspace/ProductionTable/ProductionTableView.cs
@@ -730,7 +730,7 @@ public ModulesColumn(ProductionTableView view) : base(view, LSs.ProductionTableH
             => moduleTemplateList = new VirtualScrollList<ProjectModuleTemplate>(15f, new Vector2(20f, 2.5f), ModuleTemplateDrawer, collapsible: true);
 
         private void ModuleTemplateDrawer(ImGui gui, ProjectModuleTemplate element, int index) {
-            var evt = gui.BuildContextMenuButton(element.name, icon: element.icon?.icon ?? default, disabled: !element.template.IsCompatibleWith(editingRecipeModules));
+            var evt = gui.BuildContextMenuButton(element.name, icon: element.icon?.GetIcon() ?? default, disabled: !element.template.IsCompatibleWith(editingRecipeModules));
 
             if (evt == ButtonEvent.Click && gui.CloseDropdown()) {
                 var copied = JsonUtils.Copy(element.template, editingRecipeModules, null);
diff --git a/Yafc/Workspace/SummaryView.cs b/Yafc/Workspace/SummaryView.cs
index c204797c..68d865dd 100644
--- a/Yafc/Workspace/SummaryView.cs
+++ b/Yafc/Workspace/SummaryView.cs
@@ -41,7 +41,7 @@ public override void BuildElement(ImGui gui, ProjectPage page) {
                 gui.spacing = 0.2f;
 
                 if (page.icon != null) {
-                    gui.BuildIcon(page.icon.icon, FirstColumnIconSize);
+                    gui.BuildIcon(page.icon.GetIcon(), FirstColumnIconSize);
                 }
                 else {
                     _ = gui.AllocateRect(0f, FirstColumnIconSize);