diff --git a/packages/viewer/src/components/viewer/index.tsx b/packages/viewer/src/components/viewer/index.tsx
index 6f07db6d4..f6fa42315 100644
--- a/packages/viewer/src/components/viewer/index.tsx
+++ b/packages/viewer/src/components/viewer/index.tsx
@@ -8,7 +8,7 @@ import {
   useScene,
 } from '@pascal-app/core'
 import { Canvas, extend, type ThreeToJSXElements, useFrame, useThree } from '@react-three/fiber'
-import { forwardRef, useEffect, useImperativeHandle, useRef } from 'react'
+import { forwardRef, useEffect, useImperativeHandle, useMemo, useRef, useState } from 'react'
 import * as THREE from 'three/webgpu'
 import { hasDrawableGeometry } from '../../lib/drawable-geometry'
 import { PERF_OVERLAY_ENABLED, pushGpuSample } from '../../lib/gpu-perf'
@@ -66,6 +66,38 @@ const DIRTY_BUILD_KINDS = new Set([
 
 const warnedEmptyDraw = process.env.NODE_ENV === 'production' ? null : new WeakSet<object>()
 
+function canCreateWebGLContext() {
+  if (typeof document === 'undefined') return false
+
+  const canvas = document.createElement('canvas')
+  try {
+    return Boolean(canvas.getContext('webgl2') ?? canvas.getContext('webgl'))
+  } catch {
+    return false
+  }
+}
+
+function canMountGpuViewer() {
+  if (typeof window === 'undefined') return false
+  if (!('gpu' in navigator) && !canCreateWebGLContext()) return false
+
+  return true
+}
+
+function UnsupportedGpuViewerFallback() {
+  return (
+    <div className="flex h-full min-h-64 w-full items-center justify-center bg-[#fafafa] p-6 text-center text-neutral-900">
+      <div className="max-w-md rounded-2xl border border-neutral-200 bg-white p-6 shadow-sm">
+        <h2 className="font-semibold text-lg">3D viewer unavailable</h2>
+        <p className="mt-2 text-neutral-600 text-sm">
+          This browser or environment does not expose WebGPU or WebGL, so Pascal cannot render the
+          3D scene here. Try opening the editor in a browser with hardware acceleration enabled.
+        </p>
+      </div>
+    </div>
+  )
+}
+
 /**
  * Renderer-level safety net against the empty-vertex-buffer crash.
  *
@@ -341,6 +373,9 @@ const Viewer = forwardRef<ViewerHandle, ViewerProps>(function Viewer(
     }
   }, [isolate])
 
+  const [rendererInitFailed, setRendererInitFailed] = useState(false)
+  const canMountViewer = useMemo(canMountGpuViewer, [])
+
   const isDark = useViewer((state) => getSceneTheme(state.sceneTheme).appearance === 'dark')
   const defaultShading = defaultRender?.shading
   const defaultTextures = defaultRender?.textures
@@ -383,6 +418,10 @@ const Viewer = forwardRef<ViewerHandle, ViewerProps>(function Viewer(
   // Desktops (fine pointer) keep the original 1.5 cap.
   const maxDpr =
     typeof window !== 'undefined' && window.matchMedia('(pointer: coarse)').matches ? 1.25 : 1.5
+  if (!canMountViewer || rendererInitFailed) {
+    return <UnsupportedGpuViewerFallback />
+  }
+
   return (
     <Canvas
       camera={{ position: [50, 50, 50], fov: 50 }}
@@ -410,6 +449,7 @@ const Viewer = forwardRef<ViewerHandle, ViewerProps>(function Viewer(
               // rejection forever.
               if (canvas) WEBGPU_RENDERER_CACHE.delete(canvas)
               console.error('[viewer] WebGPURenderer init failed', err)
+              setRendererInitFailed(true)
               throw err
             }
           })()