diff --git a/apps/editor/app/viewer/[id]/viewer-overlay.tsx b/apps/editor/app/viewer/[id]/viewer-overlay.tsx
index 03ff3721..d626c39d 100644
--- a/apps/editor/app/viewer/[id]/viewer-overlay.tsx
+++ b/apps/editor/app/viewer/[id]/viewer-overlay.tsx
@@ -68,6 +68,8 @@ interface ViewerOverlayProps {
   owner?: ProjectOwner | null
   canShowScans?: boolean
   canShowGuides?: boolean
+  onBack?: () => void
+  hideCollections?: boolean
 }
 
 export const ViewerOverlay = ({
@@ -75,6 +77,8 @@ export const ViewerOverlay = ({
   owner,
   canShowScans = true,
   canShowGuides = true,
+  onBack,
+  hideCollections,
 }: ViewerOverlayProps) => {
   const selection = useViewer((s) => s.selection)
   const nodes = useScene((s) => s.nodes)
@@ -130,12 +134,21 @@ export const ViewerOverlay = ({
         <div className="pointer-events-auto flex flex-col rounded-2xl border border-border/40 bg-background/95 shadow-lg backdrop-blur-xl transition-colors duration-200 ease-out overflow-hidden min-w-[200px]">
           {/* Project info + back */}
           <div className="flex items-center gap-3 px-3 py-2.5">
-            <Link
-              href="/"
-              className="flex h-7 w-7 shrink-0 items-center justify-center rounded-md hover:bg-white/10 transition-colors"
-            >
-              <ArrowLeft className="h-4 w-4 text-muted-foreground" />
-            </Link>
+            {onBack ? (
+              <button
+                onClick={onBack}
+                className="flex h-7 w-7 shrink-0 items-center justify-center rounded-md hover:bg-white/10 transition-colors"
+              >
+                <ArrowLeft className="h-4 w-4 text-muted-foreground" />
+              </button>
+            ) : (
+              <Link
+                href="/"
+                className="flex h-7 w-7 shrink-0 items-center justify-center rounded-md hover:bg-white/10 transition-colors"
+              >
+                <ArrowLeft className="h-4 w-4 text-muted-foreground" />
+              </Link>
+            )}
             <div className="min-w-0">
               <div className="text-sm font-medium text-foreground truncate">
                 {projectName || 'Untitled'}
@@ -248,9 +261,11 @@ export const ViewerOverlay = ({
       </div>
 
       {/* Collections Panel - Top Right */}
-      <div className="absolute top-4 right-4 z-20 flex flex-col gap-3 dark text-foreground">
-        <CollectionsPanel />
-      </div>
+      {!hideCollections && (
+        <div className="absolute top-4 right-4 z-20 flex flex-col gap-3 dark text-foreground">
+          <CollectionsPanel />
+        </div>
+      )}
 
       {/* Controls Panel - Bottom Center */}
       <div className="absolute bottom-6 left-1/2 -translate-x-1/2 z-20 dark text-foreground">
diff --git a/apps/editor/components/editor/custom-camera-controls.tsx b/apps/editor/components/editor/custom-camera-controls.tsx
index 21dfb4da..2c3314cd 100644
--- a/apps/editor/components/editor/custom-camera-controls.tsx
+++ b/apps/editor/components/editor/custom-camera-controls.tsx
@@ -5,14 +5,20 @@ import { useViewer } from '@pascal-app/viewer'
 import { CameraControls, CameraControlsImpl } from '@react-three/drei'
 import { useThree } from '@react-three/fiber'
 import { useCallback, useEffect, useMemo, useRef } from 'react'
-import { Vector3 } from 'three'
+import { Box3, Vector3 } from 'three'
 import { EDITOR_LAYER } from '@/lib/constants'
+import useEditor from '@/store/use-editor'
 
 const currentTarget = new Vector3()
+const tempBox = new Box3()
+const tempCenter = new Vector3()
+const tempSize = new Vector3()
 
 export const CustomCameraControls = () => {
   const controls = useRef<CameraControlsImpl>(null!)
-  const currentLevelId = useViewer((state) => state.selection.levelId)
+  const isPreviewMode = useEditor((s) => s.isPreviewMode)
+  const selection = useViewer((s) => s.selection)
+  const currentLevelId = selection.levelId
   const firstLoad = useRef(true)
 
   const camera = useThree((state) => state.camera)
@@ -23,6 +29,7 @@ export const CustomCameraControls = () => {
   }, [camera, raycaster])
 
   useEffect(() => {
+    if (isPreviewMode) return // Preview mode uses auto-navigate instead
     let targetY = 0
     if (currentLevelId) {
       const levelMesh = sceneRegistry.nodes.get(currentLevelId)
@@ -41,7 +48,7 @@ export const CustomCameraControls = () => {
       currentTarget.z,
       true,
     )
-  }, [currentLevelId])
+  }, [currentLevelId, isPreviewMode])
 
   // Configure mouse buttons based on control mode and camera mode
   const cameraMode = useViewer((state) => state.cameraMode)
@@ -53,12 +60,14 @@ export const CustomCameraControls = () => {
         : CameraControlsImpl.ACTION.DOLLY
 
     return {
-      left: CameraControlsImpl.ACTION.NONE,
+      left: isPreviewMode
+        ? CameraControlsImpl.ACTION.SCREEN_PAN
+        : CameraControlsImpl.ACTION.NONE,
       middle: CameraControlsImpl.ACTION.SCREEN_PAN,
       right: CameraControlsImpl.ACTION.ROTATE,
       wheel: wheelAction,
     }
-  }, [cameraMode])
+  }, [cameraMode, isPreviewMode])
 
   useEffect(() => {
     const keyState = {
@@ -81,11 +90,15 @@ export const CustomCameraControls = () => {
           ? CameraControlsImpl.ACTION.ZOOM
           : CameraControlsImpl.ACTION.DOLLY
       controls.current.mouseButtons.wheel = wheelAction
-      controls.current.mouseButtons.left = CameraControlsImpl.ACTION.NONE
       controls.current.mouseButtons.middle = CameraControlsImpl.ACTION.SCREEN_PAN
       controls.current.mouseButtons.right = CameraControlsImpl.ACTION.ROTATE
-      if (space) {
+      if (isPreviewMode) {
+        // In preview mode, left-click is always pan (viewer-style)
         controls.current.mouseButtons.left = CameraControlsImpl.ACTION.SCREEN_PAN
+      } else if (space) {
+        controls.current.mouseButtons.left = CameraControlsImpl.ACTION.SCREEN_PAN
+      } else {
+        controls.current.mouseButtons.left = CameraControlsImpl.ACTION.NONE
       }
     }
 
@@ -137,7 +150,62 @@ export const CustomCameraControls = () => {
       document.removeEventListener('keydown', onKeyDown)
       document.removeEventListener('keyup', onKeyUp)
     }
-  }, [cameraMode])
+  }, [cameraMode, isPreviewMode])
+
+  // Preview mode: auto-navigate camera to selected node (viewer behavior)
+  const previewTargetNodeId = isPreviewMode
+    ? (selection.zoneId ?? selection.levelId ?? selection.buildingId)
+    : null
+
+  useEffect(() => {
+    if (!isPreviewMode || !controls.current) return
+
+    const nodes = useScene.getState().nodes
+    let node = previewTargetNodeId ? nodes[previewTargetNodeId] : null
+
+    if (!previewTargetNodeId) {
+      const site = Object.values(nodes).find((n) => n.type === 'site')
+      node = site || null
+    }
+    if (!node) return
+
+    // Check if node has a saved camera
+    if (node.camera) {
+      const { position, target } = node.camera
+      requestAnimationFrame(() => {
+        if (!controls.current) return
+        controls.current.setLookAt(
+          position[0], position[1], position[2],
+          target[0], target[1], target[2],
+          true,
+        )
+      })
+      return
+    }
+
+    if (!previewTargetNodeId) return
+
+    // Calculate camera position from bounding box
+    const object3D = sceneRegistry.nodes.get(previewTargetNodeId)
+    if (!object3D) return
+
+    tempBox.setFromObject(object3D)
+    tempBox.getCenter(tempCenter)
+    tempBox.getSize(tempSize)
+
+    const maxDim = Math.max(tempSize.x, tempSize.y, tempSize.z)
+    const distance = Math.max(maxDim * 2, 15)
+
+    controls.current.setLookAt(
+      tempCenter.x + distance * 0.7,
+      tempCenter.y + distance * 0.5,
+      tempCenter.z + distance * 0.7,
+      tempCenter.x,
+      tempCenter.y,
+      tempCenter.z,
+      true,
+    )
+  }, [isPreviewMode, previewTargetNodeId])
 
   useEffect(() => {
     const handleNodeCapture = ({ nodeId }: CameraControlEvent) => {
diff --git a/apps/editor/components/editor/index.tsx b/apps/editor/components/editor/index.tsx
index ee41bdd3..e3a329e7 100644
--- a/apps/editor/components/editor/index.tsx
+++ b/apps/editor/components/editor/index.tsx
@@ -1,15 +1,18 @@
 'use client'
 
 import { initSpaceDetectionSync, initSpatialGridSync, useScene } from '@pascal-app/core'
-import { useViewer, Viewer } from '@pascal-app/viewer'
+import { InteractiveSystem, useViewer, Viewer } from '@pascal-app/viewer'
 import { useEffect } from 'react'
 import { useProjectScene } from '@/features/community/lib/models/hooks'
 import { useProjectStore } from '@/features/community/lib/projects/store'
 import { useKeyboard } from '@/hooks/use-keyboard'
 import { initSFXBus } from '@/lib/sfx-bus'
 import useEditor from '@/store/use-editor'
+import { ViewerOverlay } from '@/app/viewer/[id]/viewer-overlay'
+import { ViewerZoneSystem } from '@/app/viewer/[id]/viewer-zone-system'
 import { FeedbackDialog } from '../feedback-dialog'
 import { PascalRadio } from '../pascal-radio'
+import { PreviewButton } from '../preview-button'
 import { CeilingSystem } from '../systems/ceiling/ceiling-system'
 import { ZoneLabelEditorSystem } from '../systems/zone/zone-label-editor-system'
 import { ZoneSystem } from '../systems/zone/zone-system'
@@ -102,6 +105,8 @@ export default function Editor({ projectId }: EditorProps) {
   const isProjectLoading = useProjectStore((state) => state.isLoading)
   const isSceneLoading = useProjectStore((state) => state.isSceneLoading)
   const isLoading = isProjectLoading || isSceneLoading
+  const isPreviewMode = useEditor((s) => s.isPreviewMode)
+  const activeProject = useProjectStore((s) => s.activeProject)
 
   useEffect(() => {
     if (projectId) {
@@ -121,40 +126,56 @@ export default function Editor({ projectId }: EditorProps) {
   return (
     <div className="w-full h-full dark text-foreground">
       {isLoading && <SceneLoader />}
-      <ActionMenu />
-      <PanelManager />
-      <HelperManager />
 
-      {/* Top-right controls */}
-      <div className="pointer-events-none fixed top-4 right-4 z-50 flex items-start gap-2">
-        <div className="pointer-events-auto">
-          <PascalRadio />
-        </div>
-        <div className="pointer-events-auto">
-          <FeedbackDialog projectId={projectId} />
-        </div>
-      </div>
+      {isPreviewMode ? (
+        <ViewerOverlay
+          projectName={activeProject?.name}
+          onBack={() => useEditor.getState().setPreviewMode(false)}
+        />
+      ) : (
+        <>
+          <ActionMenu />
+          <PanelManager />
+          <HelperManager />
+
+          {/* Top-right controls */}
+          <div className="pointer-events-none fixed top-4 right-4 z-50 flex items-start gap-2">
+            <div className="pointer-events-auto">
+              <PreviewButton />
+            </div>
+            <div className="pointer-events-auto">
+              <PascalRadio />
+            </div>
+            <div className="pointer-events-auto">
+              <FeedbackDialog projectId={projectId} />
+            </div>
+          </div>
+
+          <SidebarProvider className="fixed z-20">
+            <AppSidebar />
+          </SidebarProvider>
+        </>
+      )}
 
-      <SidebarProvider className="fixed z-20">
-        <AppSidebar />
-      </SidebarProvider>
       <ErrorBoundary key={projectId} fallback={<EditorSceneCrashFallback />}>
-        <Viewer selectionManager="custom">
-          <SelectionManager />
-          <FloatingActionMenu />
+        <Viewer selectionManager={isPreviewMode ? 'default' : 'custom'}>
+          {!isPreviewMode && <SelectionManager />}
+          {!isPreviewMode && <FloatingActionMenu />}
           <ExportManager />
-          {/* Editor only system to toggle zone visibility */}
-          <ZoneSystem />
+          {/* Swap zone systems: viewer drill-down vs editor layer toggle */}
+          {isPreviewMode ? <ViewerZoneSystem /> : <ZoneSystem />}
           <CeilingSystem />
-          {/* <Stats /> */}
-          <Grid cellColor="#aaa" sectionColor="#ccc" fadeDistance={500} />
-          <ToolManager />
+          {!isPreviewMode && (
+            <Grid cellColor="#aaa" sectionColor="#ccc" fadeDistance={500} />
+          )}
+          {!isPreviewMode && <ToolManager />}
           <CustomCameraControls />
           <ThumbnailGenerator projectId={projectId} />
           <PresetThumbnailGenerator />
-          <SiteEdgeLabels />
+          {!isPreviewMode && <SiteEdgeLabels />}
+          {isPreviewMode && <InteractiveSystem />}
         </Viewer>
-        <ZoneLabelEditorSystem />
+        {!isPreviewMode && <ZoneLabelEditorSystem />}
       </ErrorBoundary>
     </div>
   )
diff --git a/apps/editor/components/preview-button.tsx b/apps/editor/components/preview-button.tsx
new file mode 100644
index 00000000..97af7158
--- /dev/null
+++ b/apps/editor/components/preview-button.tsx
@@ -0,0 +1,16 @@
+'use client'
+
+import { Eye } from 'lucide-react'
+import useEditor from '@/store/use-editor'
+
+export function PreviewButton() {
+  return (
+    <button
+      onClick={() => useEditor.getState().setPreviewMode(true)}
+      className="flex items-center gap-2 rounded-lg border border-border bg-background/95 shadow-lg backdrop-blur-md px-3 py-2 text-sm font-medium cursor-pointer hover:bg-accent/90 transition-colors"
+    >
+      <Eye className="h-4 w-4 shrink-0" />
+      <span className="hidden sm:inline whitespace-nowrap">Preview</span>
+    </button>
+  )
+}
diff --git a/apps/editor/components/ui/sidebar/app-sidebar.tsx b/apps/editor/components/ui/sidebar/app-sidebar.tsx
index 247a729f..4766e6aa 100644
--- a/apps/editor/components/ui/sidebar/app-sidebar.tsx
+++ b/apps/editor/components/ui/sidebar/app-sidebar.tsx
@@ -19,6 +19,7 @@ import {
   Sidebar,
   SidebarContent,
   SidebarHeader,
+  useSidebarStore,
 } from "@/components/ui/primitives/sidebar";
 import {
   Popover,
@@ -108,6 +109,11 @@ export function AppSidebar() {
 
   useEffect(() => {
     setMounted(true);
+    // Widen default sidebar (288px → 432px) for better project title visibility
+    const store = useSidebarStore.getState();
+    if (store.width <= 288) {
+      store.setWidth(432);
+    }
   }, []);
 
   useEffect(() => {
diff --git a/apps/editor/store/use-editor.tsx b/apps/editor/store/use-editor.tsx
index 61191140..1d97d24f 100644
--- a/apps/editor/store/use-editor.tsx
+++ b/apps/editor/store/use-editor.tsx
@@ -76,6 +76,9 @@ type EditorState = {
   // Generic hole editing (works for slabs, ceilings, and any future polygon nodes)
   editingHole: { nodeId: string; holeIndex: number } | null
   setEditingHole: (hole: { nodeId: string; holeIndex: number } | null) => void
+  // Preview mode (viewer-like experience inside the editor)
+  isPreviewMode: boolean
+  setPreviewMode: (preview: boolean) => void
 }
 
 const useEditor = create<EditorState>()((set, get) => ({
@@ -219,6 +222,16 @@ const useEditor = create<EditorState>()((set, get) => ({
   setSpaces: (spaces) => set({ spaces }),
   editingHole: null,
   setEditingHole: (hole) => set({ editingHole: hole }),
+  isPreviewMode: false,
+  setPreviewMode: (preview) => {
+    if (preview) {
+      set({ isPreviewMode: true, mode: 'select', tool: null, catalogCategory: null })
+      // Clear zone/item selection for clean viewer drill-down hierarchy
+      useViewer.getState().setSelection({ selectedIds: [], zoneId: null })
+    } else {
+      set({ isPreviewMode: false })
+    }
+  },
 }))
 
 export default useEditor