diff --git a/src/app/editor-store.ts b/src/app/editor-store.ts
index 0a280096..8eeba9d8 100644
--- a/src/app/editor-store.ts
+++ b/src/app/editor-store.ts
@@ -26,7 +26,8 @@ import {
   type ViewportDisplayMode,
   type ViewportLayoutMode,
   type ViewportPanelId,
-  type ViewportPanelState
+  type ViewportPanelState,
+  type ViewportQuadSplit
 } from "../viewport-three/viewport-layout";
 
 export interface EditorStoreState {
@@ -36,6 +37,7 @@ export interface EditorStoreState {
   viewportLayoutMode: ViewportLayoutMode;
   activeViewportPanelId: ViewportPanelId;
   viewportPanels: Record<ViewportPanelId, ViewportPanelState>;
+  viewportQuadSplit: ViewportQuadSplit;
   viewportTransientState: ViewportTransientState;
   canUndo: boolean;
   canRedo: boolean;
@@ -61,6 +63,7 @@ export class EditorStore {
   private viewportLayoutMode: ViewportLayoutMode = "single";
   private activeViewportPanelId: ViewportPanelId = "topLeft";
   private viewportPanels = createDefaultViewportLayoutState().panels;
+  private viewportQuadSplit = createDefaultViewportLayoutState().viewportQuadSplit;
   private viewportTransientState = createDefaultViewportTransientState();
   private previousEditingToolMode: Exclude<ToolMode, "play"> = "select";
   private readonly history = new CommandHistory();
@@ -168,6 +171,18 @@ export class EditorStore {
     this.emit();
   }
 
+  setViewportQuadSplit(viewportQuadSplit: ViewportQuadSplit) {
+    if (this.viewportQuadSplit.x === viewportQuadSplit.x && this.viewportQuadSplit.y === viewportQuadSplit.y) {
+      return;
+    }
+
+    this.viewportQuadSplit = {
+      x: viewportQuadSplit.x,
+      y: viewportQuadSplit.y
+    };
+    this.emit();
+  }
+
   setViewportToolPreview(toolPreview: ViewportToolPreview) {
     const nextToolPreview = cloneViewportToolPreview(toolPreview);
 
@@ -330,6 +345,7 @@ export class EditorStore {
       viewportLayoutMode: this.viewportLayoutMode,
       activeViewportPanelId: this.activeViewportPanelId,
       viewportPanels: this.viewportPanels,
+      viewportQuadSplit: this.viewportQuadSplit,
       viewportTransientState: this.viewportTransientState,
       canUndo: this.history.canUndo(),
       canRedo: this.history.canRedo(),
diff --git a/src/viewport-three/ViewportPanel.tsx b/src/viewport-three/ViewportPanel.tsx
index e88b9e72..f016dc18 100644
--- a/src/viewport-three/ViewportPanel.tsx
+++ b/src/viewport-three/ViewportPanel.tsx
@@ -1,3 +1,5 @@
+import type { CSSProperties } from "react";
+
 import { ViewportCanvas } from "./ViewportCanvas";
 import {
   getViewportDisplayModeLabel,
@@ -22,6 +24,8 @@ interface ViewportPanelProps {
   panelState: ViewportPanelState;
   layoutMode: ViewportLayoutMode;
   isActive: boolean;
+  className?: string;
+  style?: CSSProperties;
   world: WorldSettings;
   sceneDocument: SceneDocument;
   projectAssets: Record<string, ProjectAssetRecord>;
@@ -45,6 +49,8 @@ export function ViewportPanel({
   panelState,
   layoutMode,
   isActive,
+  className,
+  style,
   world,
   sceneDocument,
   projectAssets,
@@ -63,15 +69,16 @@ export function ViewportPanel({
   onSelectionChange
 }: ViewportPanelProps) {
   const shouldShow = layoutMode === "quad" || isActive;
+  const panelStyle = shouldShow ? style : { ...(style ?? {}), display: "none" };
 
   return (
     <section
-      className={`viewport-panel ${layoutMode === "single" ? "viewport-panel--single" : "viewport-panel--quad"}`}
+      className={`viewport-panel ${layoutMode === "single" ? "viewport-panel--single" : "viewport-panel--quad"} ${className ?? ""}`.trim()}
       data-testid={`viewport-panel-${panelId}`}
       data-active={isActive ? "true" : "false"}
       aria-hidden={shouldShow ? undefined : true}
       aria-label={`${getViewportPanelLabel(panelId)} viewport panel`}
-      style={shouldShow ? undefined : { display: "none" }}
+      style={panelStyle}
       onPointerDownCapture={() => onActivatePanel(panelId)}
       onFocusCapture={() => onActivatePanel(panelId)}
     >