diff --git a/apps/web/content/docs/api/shadcn.mdx b/apps/web/content/docs/api/shadcn.mdx
index 367a3a8f..db47b40b 100644
--- a/apps/web/content/docs/api/shadcn.mdx
+++ b/apps/web/content/docs/api/shadcn.mdx
@@ -25,7 +25,7 @@ Your app must have Tailwind CSS configured.
 <tbody>
 <tr>
 <td><code>@json-render/shadcn</code></td>
-<td><code>shadcnComponents</code></td>
+<td><code>shadcnComponents</code>, <code>PortalContainerProvider</code></td>
 <td>React implementations</td>
 </tr>
 <tr>
@@ -73,6 +73,21 @@ const { registry } = defineRegistry(catalog, {
 
 State actions (`setState`, `pushState`, `removeState`) are built into the React schema and handled by `ActionProvider` automatically. You don't need to declare them in your catalog.
 
+## Portal containers and scoped themes
+
+Dialog, DropdownMenu, Popover, Select and Tooltip normally portal to `document.body`. When the renderer lives inside a scoped theme, supply a stable host element with that theme through `PortalContainerProvider`:
+
+```tsx
+import { PortalContainerProvider } from "@json-render/shadcn";
+import { Renderer } from "@json-render/react";
+
+<PortalContainerProvider container={themedPortalElement}>
+  <Renderer spec={spec} registry={registry} />
+</PortalContainerProvider>
+```
+
+The host owns the element and its lifetime. Place it outside clipped or transformed ancestors when overlays must cover the viewport. Nested providers select their nearest container. Without a provider, or with `container={undefined}`, the standard Radix body portal remains unchanged. The provider does not change component schemas, state, actions or overlay interactions.
+
 ## Extending with Custom Components
 
 Add custom components alongside standard ones:
diff --git a/packages/shadcn/README.md b/packages/shadcn/README.md
index 8938aac8..209cd2d7 100644
--- a/packages/shadcn/README.md
+++ b/packages/shadcn/README.md
@@ -63,6 +63,21 @@ function App({ spec }) {
 }
 ```
 
+## Portal containers and scoped themes
+
+Dialog, DropdownMenu, Popover, Select and Tooltip normally portal to `document.body`. When the renderer lives inside a scoped theme, supply a stable host element with that theme through `PortalContainerProvider`:
+
+```tsx
+import { PortalContainerProvider } from "@json-render/shadcn";
+import { Renderer } from "@json-render/react";
+
+<PortalContainerProvider container={themedPortalElement}>
+  <Renderer spec={spec} registry={registry} />
+</PortalContainerProvider>
+```
+
+The host owns the element and its lifetime. Place it outside clipped or transformed ancestors when overlays must cover the viewport. Nested providers select their nearest container. Without a provider, or with `container={undefined}`, the standard Radix body portal remains unchanged. The provider does not change component schemas, state, actions or overlay interactions.
+
 ## Extending with Custom Components
 
 Pick standard components as a base and add your own alongside them:
@@ -203,7 +218,7 @@ All form components support the `validateOn` prop to control when validation run
 
 | Entry Point | Exports |
 |-------------|---------|
-| `@json-render/shadcn` | `shadcnComponents` |
+| `@json-render/shadcn` | `shadcnComponents`, `PortalContainerProvider` |
 | `@json-render/shadcn/catalog` | `shadcnComponentDefinitions` |
 
 The `/catalog` entry point contains only Zod schemas (no React dependency), so it can be used in server-side code for prompt generation.
diff --git a/packages/shadcn/src/index.ts b/packages/shadcn/src/index.ts
index fc7ef14e..a3243564 100644
--- a/packages/shadcn/src/index.ts
+++ b/packages/shadcn/src/index.ts
@@ -7,3 +7,5 @@ export {
   type ComponentDefinition,
   type ShadcnProps,
 } from "./catalog";
+
+export { PortalContainerProvider } from "./portal-container";
diff --git a/packages/shadcn/src/portal-container.tsx b/packages/shadcn/src/portal-container.tsx
new file mode 100644
index 00000000..90f82765
--- /dev/null
+++ b/packages/shadcn/src/portal-container.tsx
@@ -0,0 +1,24 @@
+"use client";
+
+import { createContext, useContext, type ReactNode } from "react";
+
+const PortalContainerContext = createContext<HTMLElement | undefined>(undefined);
+
+/** Keep shadcn portals inside the host's theme and stylesheet boundary. */
+export function PortalContainerProvider({
+  container,
+  children,
+}: {
+  container: HTMLElement | undefined;
+  children: ReactNode;
+}) {
+  return (
+    <PortalContainerContext.Provider value={container}>
+      {children}
+    </PortalContainerContext.Provider>
+  );
+}
+
+export function usePortalContainer() {
+  return useContext(PortalContainerContext);
+}
diff --git a/packages/shadcn/src/ui/dialog.tsx b/packages/shadcn/src/ui/dialog.tsx
index aa245b90..6aa0be1c 100644
--- a/packages/shadcn/src/ui/dialog.tsx
+++ b/packages/shadcn/src/ui/dialog.tsx
@@ -5,6 +5,7 @@ import { XIcon } from "lucide-react";
 import { Dialog as DialogPrimitive } from "radix-ui";
 
 import { cn } from "../lib/utils";
+import { usePortalContainer } from "../portal-container";
 import { Button } from "./button";
 
 function Dialog({
@@ -22,7 +23,8 @@ function DialogTrigger({
 function DialogPortal({
   ...props
 }: React.ComponentProps<typeof DialogPrimitive.Portal>) {
-  return <DialogPrimitive.Portal data-slot="dialog-portal" {...props} />;
+  const container = usePortalContainer();
+  return <DialogPrimitive.Portal container={container} data-slot="dialog-portal" {...props} />;
 }
 
 function DialogClose({
diff --git a/packages/shadcn/src/ui/dropdown-menu.tsx b/packages/shadcn/src/ui/dropdown-menu.tsx
index 0ca63b15..60b1ebd0 100644
--- a/packages/shadcn/src/ui/dropdown-menu.tsx
+++ b/packages/shadcn/src/ui/dropdown-menu.tsx
@@ -5,6 +5,7 @@ import { CheckIcon, ChevronRightIcon, CircleIcon } from "lucide-react";
 import { DropdownMenu as DropdownMenuPrimitive } from "radix-ui";
 
 import { cn } from "../lib/utils";
+import { usePortalContainer } from "../portal-container";
 
 function DropdownMenu({
   ...props
@@ -15,8 +16,9 @@ function DropdownMenu({
 function DropdownMenuPortal({
   ...props
 }: React.ComponentProps<typeof DropdownMenuPrimitive.Portal>) {
+  const container = usePortalContainer();
   return (
-    <DropdownMenuPrimitive.Portal data-slot="dropdown-menu-portal" {...props} />
+    <DropdownMenuPrimitive.Portal container={container} data-slot="dropdown-menu-portal" {...props} />
   );
 }
 
@@ -36,8 +38,9 @@ function DropdownMenuContent({
   sideOffset = 4,
   ...props
 }: React.ComponentProps<typeof DropdownMenuPrimitive.Content>) {
+  const container = usePortalContainer();
   return (
-    <DropdownMenuPrimitive.Portal>
+    <DropdownMenuPrimitive.Portal container={container}>
       <DropdownMenuPrimitive.Content
         data-slot="dropdown-menu-content"
         sideOffset={sideOffset}
diff --git a/packages/shadcn/src/ui/popover.tsx b/packages/shadcn/src/ui/popover.tsx
index ad451c24..ff846646 100644
--- a/packages/shadcn/src/ui/popover.tsx
+++ b/packages/shadcn/src/ui/popover.tsx
@@ -4,6 +4,7 @@ import * as React from "react";
 import { Popover as PopoverPrimitive } from "radix-ui";
 
 import { cn } from "../lib/utils";
+import { usePortalContainer } from "../portal-container";
 
 function Popover({
   ...props
@@ -23,8 +24,9 @@ function PopoverContent({
   sideOffset = 4,
   ...props
 }: React.ComponentProps<typeof PopoverPrimitive.Content>) {
+  const container = usePortalContainer();
   return (
-    <PopoverPrimitive.Portal>
+    <PopoverPrimitive.Portal container={container}>
       <PopoverPrimitive.Content
         data-slot="popover-content"
         align={align}
diff --git a/packages/shadcn/src/ui/select.tsx b/packages/shadcn/src/ui/select.tsx
index 021de09f..4cb10070 100644
--- a/packages/shadcn/src/ui/select.tsx
+++ b/packages/shadcn/src/ui/select.tsx
@@ -3,6 +3,7 @@ import { CheckIcon, ChevronDownIcon, ChevronUpIcon } from "lucide-react";
 import { Select as SelectPrimitive } from "radix-ui";
 
 import { cn } from "../lib/utils";
+import { usePortalContainer } from "../portal-container";
 
 function Select({
   ...props
@@ -55,8 +56,9 @@ function SelectContent({
   align = "center",
   ...props
 }: React.ComponentProps<typeof SelectPrimitive.Content>) {
+  const container = usePortalContainer();
   return (
-    <SelectPrimitive.Portal>
+    <SelectPrimitive.Portal container={container}>
       <SelectPrimitive.Content
         data-slot="select-content"
         className={cn(
diff --git a/packages/shadcn/src/ui/tooltip.tsx b/packages/shadcn/src/ui/tooltip.tsx
index 3ea265ab..096466d8 100644
--- a/packages/shadcn/src/ui/tooltip.tsx
+++ b/packages/shadcn/src/ui/tooltip.tsx
@@ -4,6 +4,7 @@ import * as React from "react";
 import { Tooltip as TooltipPrimitive } from "radix-ui";
 
 import { cn } from "../lib/utils";
+import { usePortalContainer } from "../portal-container";
 
 function TooltipProvider({
   delayDuration = 0,
@@ -36,8 +37,9 @@ function TooltipContent({
   children,
   ...props
 }: React.ComponentProps<typeof TooltipPrimitive.Content>) {
+  const container = usePortalContainer();
   return (
-    <TooltipPrimitive.Portal>
+    <TooltipPrimitive.Portal container={container}>
       <TooltipPrimitive.Content
         data-slot="tooltip-content"
         sideOffset={sideOffset}
diff --git a/skills/shadcn/SKILL.md b/skills/shadcn/SKILL.md
index b26c6b82..a657e339 100644
--- a/skills/shadcn/SKILL.md
+++ b/skills/shadcn/SKILL.md
@@ -157,3 +157,7 @@ All form components support `validateOn` to control when validation runs:
 - Component implementations use bundled shadcn/ui primitives (not your app's `components/ui/`)
 - All form inputs support `checks` for validation (type + message pairs) and `validateOn` for timing
 - Events: inputs emit `change`/`submit`/`focus`/`blur`; buttons emit `press`; selects emit `change`/`select`
+
+## Scoped portal containers
+
+When a renderer uses a local theme, wrap it in `PortalContainerProvider` from `@json-render/shadcn` and pass a stable themed host element through `container`. Dialog, DropdownMenu, Popover, Select and Tooltip use the nearest provider. The host owns placement and cleanup; without a provider, portals continue to use `document.body`. This is host integration, not a model-facing prop.