angular · kirjs · Apr 10, 2026 · Jan 28, 2026 · Feb 19, 2026 · Apr 6, 2026
diff --git a/integration/platform-server-hydration/size.json b/integration/platform-server-hydration/size.json
@@ -1,5 +1,5 @@
 {
-  "dist/browser/main-[hash].js": 240329,
+  "dist/browser/main-[hash].js": 240750,
   "dist/browser/polyfills-[hash].js": 35726,
   "dist/browser/event-dispatch-contract.min.js": 476
 }
diff --git a/integration/standalone-bootstrap/size.json b/integration/standalone-bootstrap/size.json
@@ -1,4 +1,4 @@
 {
-  "dist/main.js": 89237,
+  "dist/main.js": 93814,
   "dist/polyfills.js": 35677
 }
diff --git a/packages/core/src/core_private_export.ts b/packages/core/src/core_private_export.ts
@@ -61,6 +61,10 @@ export {
   DeferBlockState as ɵDeferBlockState,
 } from './defer/interfaces';
 export {getDocument as ɵgetDocument} from './render3/interfaces/document';
+export {
+  SHARED_STYLES_HOST as ɵSHARED_STYLES_HOST,
+  SharedStylesHost as ɵSharedStylesHost,
+} from './render3/interfaces/shared_styles_host';
 export {
   convertToBitFlags as ɵconvertToBitFlags,
   setCurrentInjector as ɵsetCurrentInjector,

diff --git a/packages/core/src/render3/component_ref.ts b/packages/core/src/render3/component_ref.ts
@@ -76,14 +76,20 @@ import {ProfilerEvent} from '../../primitives/devtools';
 import {executeContentQueries} from './queries/query_execution';
 import {enterView, leaveView} from './state';
 import {debugStringifyTypeForError, stringifyForError} from './util/stringify_utils';
-import {getComponentLViewByIndex, getTNode} from './util/view_utils';
+import {getComponentLViewByIndex, getTNode, storeLViewOnDestroy} from './util/view_utils';
 import {directiveHostEndFirstCreatePass, directiveHostFirstCreatePass} from './view/elements';
 import {ViewRef} from './view_ref';
 import {createLView, createTView, getInitialLViewFlagsFromDef} from './view/construction';
 import {BINDING, Binding, BindingInternal, DirectiveWithBindings} from './dynamic_bindings';
 import {NG_REFLECT_ATTRS_FLAG, NG_REFLECT_ATTRS_FLAG_DEFAULT} from '../ng_reflect';
 import {TracingService} from '../application/tracing';
 import {getComponentName} from '../internal/get_closest_component_name';
+import {SHARED_STYLES_HOST} from './interfaces/shared_styles_host';
+import {DOCUMENT} from '../document';
+import {getDocument} from './interfaces/document';
+
+const shadowRootSupported = typeof ShadowRoot !== 'undefined';
+const documentSupported = typeof Document !== 'undefined';
 
 export class ComponentFactoryResolver extends AbstractComponentFactoryResolver {
   /**
@@ -318,6 +324,14 @@ export class ComponentFactory<T> extends AbstractComponentFactory<T> {
     const hostElement = rootSelectorOrNode
       ? locateHostElement(hostRenderer, rootSelectorOrNode, cmpDef.encapsulation, rootViewInjector)
       : createHostElement(cmpDef, hostRenderer);
+
+    const sharedStylesHost = rootViewInjector.get(SHARED_STYLES_HOST, null);
+    const styleHost = getStyleHost(
+      hostElement,
+      () => rootViewInjector.get(DOCUMENT, null) ?? getDocument(),
+    );
+    if (sharedStylesHost) sharedStylesHost.addHost(styleHost);
+
     const hasInputBindings =
       componentBindings?.some(isInputBinding) ||
       directives?.some((d) => typeof d !== 'function' && d.bindings.some(isInputBinding));
@@ -336,6 +350,20 @@ export class ComponentFactory<T> extends AbstractComponentFactory<T> {
       retrieveHydrationInfo(hostElement, rootViewInjector, true /* isRootView */),
     );
 
+    // Since we don't reference count host usage, calling `removeHost` is potentially
+    // breaking since other root components on the page might rely on it (ex. a dialog,
+    // multiple `ApplicationRef.prototype.bootstrap` calls, etc.).
+    //
+    // Instead we only remove shadow roots, under the assumption that a shadow root will
+    // only contain one Angular root component. This is true for MicA, but not in general.
+    // Styles in the document light DOM are effectively leaked, since we can't easily
+    // assume no other components exist on the page outside this one root.
+    if (sharedStylesHost && shadowRootSupported && styleHost instanceof ShadowRoot) {
+      storeLViewOnDestroy(rootLView, () => {
+        sharedStylesHost.removeHost(styleHost);
+      });
+    }
+
     rootLView[HEADER_OFFSET] = hostElement;
 
     // rootView is the parent when bootstrapping
@@ -482,6 +510,20 @@ function createRootTView(
   return rootTView;
 }
 
+function getStyleHost(node: RNode, doc: () => Document): Node {
+  const rootNode = node.getRootNode?.();
+
+  if (documentSupported && rootNode instanceof Document) {
+    return rootNode.head; // Connected to document.
+  } else if (!rootNode) {
+    return doc().head; // `getRootNode` not supported, Node.js use case.
+  } else if (shadowRootSupported && rootNode instanceof ShadowRoot) {
+    return rootNode; // Shadow root
+  } else {
+    return doc().head; // Disconnected element, use fallback document.
+  }
+}
+
 function getRootTViewTemplate(
   creationBindings: Binding[] | null,
   updateBindings: Binding[] | null,

diff --git a/packages/core/src/render3/interfaces/renderer_dom.ts b/packages/core/src/render3/interfaces/renderer_dom.ts
@@ -52,6 +52,16 @@ export interface RNode {
    * Used exclusively for building up DOM which are static (ie not View roots)
    */
   appendChild(newChild: RNode): RNode;
+
+  /**
+   * Returns the root node containing this node. This is either:
+   * 1. The `Document` containing the node, if attached in light DOM.
+   * 2. The `ShadowRoot` containing the node, if attached in shadow DOM.
+   * 3. The root node of a detached tree.
+   *
+   * @see https://developer.mozilla.org/en-US/docs/Web/API/Node/getRootNode
+   */
+  getRootNode?(options?: {composed?: boolean}): RNode;
 }
 
 /**

diff --git a/packages/core/src/render3/interfaces/shared_styles_host.ts b/packages/core/src/render3/interfaces/shared_styles_host.ts
@@ -0,0 +1,47 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.dev/license
+ */
+
+import {InjectionToken} from '../../di/injection_token';
+
+/** Token used to retrieve the `SharedStylesHost`. */
+export const SHARED_STYLES_HOST = new InjectionToken<SharedStylesHost>(
+  typeof ngDevMode !== 'undefined' && ngDevMode ? 'SHARED_STYLES_HOST' : '',
+);
+
+/** Manages stylesheets for components in the application. */
+export interface SharedStylesHost {
+  /**
+   * Adds embedded styles to the DOM via HTML `style` elements.
+   * @param styles An array of style content strings.
+   * @param urls An array of URLs to be added as link tags.
+   */
+  addStyles(styles: string[], urls?: string[]): void;
+
+  /**
+   * Removes embedded styles from the DOM that were added as HTML `style` elements.
+   * @param styles An array of style content strings.
+   * @param urls An array of URLs to be removed as link tags.
+   */
+  removeStyles(styles: string[], urls?: string[]): void;
+
+  /**
+   * Adds a host node to contain styles added to the DOM and adds all existing style usage to
+   * the newly added host node.
+   *
+   * @param hostNode The node to contain styles added to the DOM.
+   */
+  addHost(hostNode: Node): void;
+
+  /**
+   * Removes a host node from the set of style hosts and removes all existing style usage from
+   * the removed host node.
+   *
+   * @param hostNode The node to remove from the set of style hosts.
+   */
+  removeHost(hostNode: Node): void;
+}
diff --git a/packages/core/test/bundling/animations-standalone/bundle.golden_symbols.json b/packages/core/test/bundling/animations-standalone/bundle.golden_symbols.json
@@ -226,6 +226,7 @@
       "SELF_TOKEN",
       "SELF_TOKEN_REGEX",
       "SHARED_ANIMATION_PROVIDERS",
+      "SHARED_STYLES_HOST",
       "SIGNAL",
       "SIMPLE_CHANGES_STORE",
       "STABILITY_WARNING_THRESHOLD",
@@ -450,6 +451,7 @@
       "directiveHostEndFirstCreatePass",
       "directiveHostFirstCreatePass",
       "documentElement",
+      "documentSupported",
       "domOnlyFirstCreatePass",
       "elementLikeEndShared",
       "elementLikeStartShared",
@@ -504,6 +506,7 @@
       "getDOM",
       "getDeclarationTNode",
       "getDirectiveDef",
+      "getDocument",
       "getElementDepthCount",
       "getFactoryDef",
       "getFirstLContainer",
@@ -549,6 +552,7 @@
       "getSelectedIndex",
       "getSelectedTNode",
       "getSimpleChangesStore",
+      "getStyleHost",
       "getTNode",
       "getTNodeFromLView",
       "getTView",
@@ -829,6 +833,7 @@
       "setupInitialInputs",
       "setupSelectorMatchedInputsOrOutputs",
       "setupStaticAttributes",
+      "shadowRootSupported",
       "shimContentAttribute",
       "shimHostAttribute",
       "shimStylesContent",

diff --git a/packages/core/test/bundling/create_component/bundle.golden_symbols.json b/packages/core/test/bundling/create_component/bundle.golden_symbols.json
@@ -173,6 +173,7 @@
       "RuntimeError",
       "SCHEDULE_IN_ROOT_ZONE",
       "SCHEDULE_IN_ROOT_ZONE_DEFAULT",
+      "SHARED_STYLES_HOST",
       "SIGNAL",
       "SIGNAL_NODE",
       "SIMPLE_CHANGES_STORE",
@@ -361,6 +362,7 @@
       "diPublicInInjector",
       "directiveHostEndFirstCreatePass",
       "directiveHostFirstCreatePass",
+      "documentSupported",
       "enterDI",
       "enterView",
       "epoch",
@@ -407,6 +409,7 @@
       "getDOM",
       "getDeclarationTNode",
       "getDirectiveDef",
+      "getDocument",
       "getFactoryDef",
       "getFirstLContainer",
       "getFirstNativeNode",
@@ -453,6 +456,7 @@
       "getSelectedIndex",
       "getSelectedTNode",
       "getSimpleChangesStore",
+      "getStyleHost",
       "getTNode",
       "getTNodeFromLView",
       "getTView",
@@ -679,6 +683,7 @@
       "setupInitialInputs",
       "setupSelectorMatchedInputsOrOutputs",
       "setupStaticAttributes",
+      "shadowRootSupported",
       "shimContentAttribute",
       "shimHostAttribute",
       "shimStylesContent",

diff --git a/packages/core/test/bundling/defer/bundle.golden_symbols.json b/packages/core/test/bundling/defer/bundle.golden_symbols.json
@@ -216,6 +216,7 @@
       "RuntimeError",
       "SCHEDULE_IN_ROOT_ZONE",
       "SCHEDULE_IN_ROOT_ZONE_DEFAULT",
+      "SHARED_STYLES_HOST",
       "SIGNAL",
       "SIMPLE_CHANGES_STORE",
       "SSR_BLOCK_STATE",
@@ -401,6 +402,7 @@
       "diPublicInInjector",
       "directiveHostEndFirstCreatePass",
       "directiveHostFirstCreatePass",
+      "documentSupported",
       "domOnlyFirstCreatePass",
       "elementLikeEndShared",
       "elementLikeStartShared",
@@ -450,6 +452,7 @@
       "getDeclarationTNode",
       "getDeferBlockDataIndex",
       "getDirectiveDef",
+      "getDocument",
       "getElementDepthCount",
       "getFactoryDef",
       "getFirstLContainer",
@@ -499,6 +502,7 @@
       "getSelectedIndex",
       "getSelectedTNode",
       "getSimpleChangesStore",
+      "getStyleHost",
       "getTDeferBlockDetails",
       "getTNode",
       "getTNodeFromLView",
@@ -722,6 +726,7 @@
       "setupInitialInputs",
       "setupSelectorMatchedInputsOrOutputs",
       "setupStaticAttributes",
+      "shadowRootSupported",
       "shouldAddViewToDom",
       "shouldAttachRegularTrigger",
       "shouldAttachTrigger",

diff --git a/packages/core/test/bundling/forms_reactive/bundle.golden_symbols.json b/packages/core/test/bundling/forms_reactive/bundle.golden_symbols.json
@@ -238,6 +238,7 @@
       "RuntimeError",
       "SCHEDULE_IN_ROOT_ZONE",
       "SCHEDULE_IN_ROOT_ZONE_DEFAULT",
+      "SHARED_STYLES_HOST",
       "SIGNAL",
       "SIGNAL_NODE",
       "SIMPLE_CHANGES_STORE",
@@ -520,6 +521,7 @@
       "diPublicInInjector",
       "directiveHostEndFirstCreatePass",
       "directiveHostFirstCreatePass",
+      "documentSupported",
       "effect",
       "elementAttributeInternal",
       "elementLikeEndShared",
@@ -593,6 +595,7 @@
       "getDOM",
       "getDeclarationTNode",
       "getDirectiveDef",
+      "getDocument",
       "getElementDepthCount",
       "getFactoryDef",
       "getFactoryOf",
@@ -646,6 +649,7 @@
       "getSelectedIndex",
       "getSelectedTNode",
       "getSimpleChangesStore",
+      "getStyleHost",
       "getSuperType",
       "getSymbolIterator",
       "getTNode",
@@ -1010,6 +1014,7 @@
       "setupInitialInputs",
       "setupSelectorMatchedInputsOrOutputs",
       "setupStaticAttributes",
+      "shadowRootSupported",
       "shimContentAttribute",
       "shimHostAttribute",
       "shimStylesContent",

diff --git a/packages/core/test/bundling/forms_template_driven/bundle.golden_symbols.json b/packages/core/test/bundling/forms_template_driven/bundle.golden_symbols.json
@@ -230,6 +230,7 @@
       "RuntimeError",
       "SCHEDULE_IN_ROOT_ZONE",
       "SCHEDULE_IN_ROOT_ZONE_DEFAULT",
+      "SHARED_STYLES_HOST",
       "SIGNAL",
       "SIGNAL_NODE",
       "SIMPLE_CHANGES_STORE",
@@ -517,6 +518,7 @@
       "diPublicInInjector",
       "directiveHostEndFirstCreatePass",
       "directiveHostFirstCreatePass",
+      "documentSupported",
       "effect",
       "elementAttributeInternal",
       "elementLikeEndShared",
@@ -589,6 +591,7 @@
       "getDOM",
       "getDeclarationTNode",
       "getDirectiveDef",
+      "getDocument",
       "getElementDepthCount",
       "getFactoryDef",
       "getFactoryOf",
@@ -642,6 +645,7 @@
       "getSelectedIndex",
       "getSelectedTNode",
       "getSimpleChangesStore",
+      "getStyleHost",
       "getSuperType",
       "getSymbolIterator",
       "getTNode",
@@ -1008,6 +1012,7 @@
       "setupInitialInputs",
       "setupSelectorMatchedInputsOrOutputs",
       "setupStaticAttributes",
+      "shadowRootSupported",
       "shimContentAttribute",
       "shimHostAttribute",
       "shimStylesContent",

diff --git a/packages/core/test/bundling/hydration/bundle.golden_symbols.json b/packages/core/test/bundling/hydration/bundle.golden_symbols.json
@@ -255,6 +255,7 @@
       "RuntimeError",
       "SCHEDULE_IN_ROOT_ZONE",
       "SCHEDULE_IN_ROOT_ZONE_DEFAULT",
+      "SHARED_STYLES_HOST",
       "SIGNAL",
       "SIMPLE_CHANGES_STORE",
       "SKIP_HYDRATION_ATTR_NAME",
@@ -499,6 +500,7 @@
       "diPublicInInjector",
       "directiveHostEndFirstCreatePass",
       "directiveHostFirstCreatePass",
+      "documentSupported",
       "enableApplyRootElementTransformImpl",
       "enableFindMatchingDehydratedViewImpl",
       "enableHydrationRuntimeSupport",
@@ -645,6 +647,7 @@
       "getSelectedIndex",
       "getSerializedContainerViews",
       "getSimpleChangesStore",
+      "getStyleHost",
       "getSymbolIterator",
       "getTDeferBlockDetails",
       "getTNode",
@@ -969,6 +972,7 @@
       "setupInitialInputs",
       "setupSelectorMatchedInputsOrOutputs",
       "setupStaticAttributes",
+      "shadowRootSupported",
       "sharedMapFunction",
       "sharedStashFunction",
       "shimContentAttribute",