diff --git a/packages/backend/src/server/web/ClientServerService.ts b/packages/backend/src/server/web/ClientServerService.ts
index ab03489c0d..8554e98aec 100644
--- a/packages/backend/src/server/web/ClientServerService.ts
+++ b/packages/backend/src/server/web/ClientServerService.ts
@@ -751,7 +751,7 @@ export class ClientServerService {
 		});
 		//#endregion
 
-		//region noindex pages
+		//#region noindex pages
 		// Tags
 		fastify.get<{ Params: { clip: string; } }>('/tags/:tag', async (request, reply) => {
 			return await renderBase(reply, { noindex: true });
@@ -761,7 +761,13 @@ export class ClientServerService {
 		fastify.get<{ Params: { clip: string; } }>('/user-tags/:tag', async (request, reply) => {
 			return await renderBase(reply, { noindex: true });
 		});
-		//endregion
+		//#endregion
+
+		//#region embed pages
+		fastify.get('/embed/:path(.*)', async (request, reply) => {
+			reply.removeHeader('X-Frame-Options');
+			return await renderBase(reply, { noindex: true });
+		});
 
 		fastify.get('/_info_card_', async (request, reply) => {
 			const meta = await this.metaService.fetch(true);
@@ -776,6 +782,7 @@ export class ClientServerService {
 				originalNotesCount: await this.notesRepository.countBy({ userHost: IsNull() }),
 			});
 		});
+		//#endregion
 
 		fastify.get('/bios', async (request, reply) => {
 			return await reply.view('bios', {
diff --git a/packages/frontend/src/_boot_.ts b/packages/frontend/src/_boot_.ts
index 875353f8a4..d44b0553f3 100644
--- a/packages/frontend/src/_boot_.ts
+++ b/packages/frontend/src/_boot_.ts
@@ -9,10 +9,19 @@ import 'vite/modulepreload-polyfill';
 import '@/style.scss';
 import { mainBoot } from '@/boot/main-boot.js';
 import { subBoot } from '@/boot/sub-boot.js';
+import { isEmbedPage } from '@/scripts/embed-page.js';
 
-const subBootPaths = ['/share', '/auth', '/miauth', '/signup-complete'];
+const subBootPaths = ['/share', '/auth', '/miauth', '/signup-complete', '/embed'];
 
 if (subBootPaths.some(i => location.pathname === i || location.pathname.startsWith(i + '/'))) {
+	if (isEmbedPage()) {
+		const params = new URLSearchParams(location.search);
+		const color = params.get('color');
+		if (color && ['light', 'dark'].includes(color)) {
+			subBoot({ forceColorMode: color as 'light' | 'dark' });
+		}
+	}
+	
 	subBoot();
 } else {
 	mainBoot();
diff --git a/packages/frontend/src/account.ts b/packages/frontend/src/account.ts
index 7f20e0b1a2..99ca5219ad 100644
--- a/packages/frontend/src/account.ts
+++ b/packages/frontend/src/account.ts
@@ -14,6 +14,7 @@ import { apiUrl } from '@/config.js';
 import { waiting, popup, popupMenu, success, alert } from '@/os.js';
 import { misskeyApi } from '@/scripts/misskey-api.js';
 import { unisonReload, reloadChannel } from '@/scripts/unison-reload.js';
+import { isEmbedPage } from '@/scripts/embed-page.js';
 
 // TODO: 他のタブと永続化されたstateを同期
 
@@ -21,8 +22,14 @@ type Account = Misskey.entities.MeDetailed & { token: string };
 
 const accountData = miLocalStorage.getItem('account');
 
+function initAccount() {
+	if (isEmbedPage()) return null;
+	if (accountData) return reactive(JSON.parse(accountData) as Account);
+	return null;
+}
+
 // TODO: 外部からはreadonlyに
-export const $i = accountData ? reactive(JSON.parse(accountData) as Account) : null;
+export const $i = initAccount();
 
 export const iAmModerator = $i != null && ($i.isAdmin === true || $i.isModerator === true);
 export const iAmAdmin = $i != null && $i.isAdmin;
@@ -78,10 +85,14 @@ export async function signout() {
 }
 
 export async function getAccounts(): Promise<{ id: Account['id'], token: Account['token'] }[]> {
+	if (isEmbedPage()) return [];
+
 	return (await get('accounts')) || [];
 }
 
 export async function addAccount(id: Account['id'], token: Account['token']) {
+	if (isEmbedPage()) return;
+
 	const accounts = await getAccounts();
 	if (!accounts.some(x => x.id === id)) {
 		await set('accounts', accounts.concat([{ id, token }]));
@@ -183,6 +194,8 @@ export async function refreshAccount() {
 }
 
 export async function login(token: Account['token'], redirect?: string) {
+	if (isEmbedPage()) return;
+
 	const showing = ref(true);
 	popup(defineAsyncComponent(() => import('@/components/MkWaitingDialog.vue')), {
 		success: false,
diff --git a/packages/frontend/src/boot/common.ts b/packages/frontend/src/boot/common.ts
index d86ae18ffe..adf3125143 100644
--- a/packages/frontend/src/boot/common.ts
+++ b/packages/frontend/src/boot/common.ts
@@ -24,7 +24,17 @@ import { miLocalStorage } from '@/local-storage.js';
 import { fetchCustomEmojis } from '@/custom-emojis.js';
 import { setupRouter } from '@/router/definition.js';
 
-export async function common(createVue: () => App<Element>) {
+export type CommonBootOptions = {
+	forceColorMode?: 'dark' | 'light' | 'auto';
+};
+
+const defaultCommonBootOptions: CommonBootOptions = {
+	forceColorMode: 'auto',
+};
+
+export async function common(createVue: () => App<Element>, partialOptions?: Partial<CommonBootOptions>) {
+	const bootOptions = Object.assign(defaultCommonBootOptions, partialOptions);
+
 	console.info(`Misskey v${version}`);
 
 	if (_DEV_) {
@@ -166,15 +176,19 @@ export async function common(createVue: () => App<Element>) {
 	});
 
 	//#region Sync dark mode
-	if (ColdDeviceStorage.get('syncDeviceDarkMode')) {
+	if (ColdDeviceStorage.get('syncDeviceDarkMode') && bootOptions.forceColorMode === 'auto') {
 		defaultStore.set('darkMode', isDeviceDarkmode());
 	}
 
 	window.matchMedia('(prefers-color-scheme: dark)').addEventListener('change', (mql) => {
-		if (ColdDeviceStorage.get('syncDeviceDarkMode')) {
+		if (ColdDeviceStorage.get('syncDeviceDarkMode') && bootOptions.forceColorMode === 'auto') {
 			defaultStore.set('darkMode', mql.matches);
 		}
 	});
+
+	if (bootOptions.forceColorMode !== 'auto') {
+		defaultStore.set('darkMode', bootOptions.forceColorMode === 'dark');
+	}
 	//#endregion
 
 	fetchInstanceMetaPromise.then(() => {
diff --git a/packages/frontend/src/boot/sub-boot.ts b/packages/frontend/src/boot/sub-boot.ts
index 017457822b..656b1bf196 100644
--- a/packages/frontend/src/boot/sub-boot.ts
+++ b/packages/frontend/src/boot/sub-boot.ts
@@ -5,9 +5,10 @@
 
 import { createApp, defineAsyncComponent } from 'vue';
 import { common } from './common.js';
+import type { CommonBootOptions } from './common.js';
 
-export async function subBoot() {
+export async function subBoot(options?: CommonBootOptions) {
 	const { isClientUpdated } = await common(() => createApp(
 		defineAsyncComponent(() => import('@/ui/minimum.vue')),
-	));
+	), options);
 }
diff --git a/packages/frontend/src/local-storage.ts b/packages/frontend/src/local-storage.ts
index 8029bca68d..59e7333fbc 100644
--- a/packages/frontend/src/local-storage.ts
+++ b/packages/frontend/src/local-storage.ts
@@ -2,8 +2,9 @@
  * SPDX-FileCopyrightText: syuilo and misskey-project
  * SPDX-License-Identifier: AGPL-3.0-only
  */
+import { isEmbedPage, initEmbedPageLocalStorage } from "@/scripts/embed-page.js";
 
-type Keys =
+export type Keys =
 	'v' |
 	'lastVersion' |
 	'instance' |
@@ -38,12 +39,33 @@ type Keys =
 	`aiscript:${string}` |
 	'lastEmojisFetchedAt' | // DEPRECATED, stored in indexeddb (13.9.0~)
 	'emojis' | // DEPRECATED, stored in indexeddb (13.9.0~);
-	`channelLastReadedAt:${string}`
+	`channelLastReadedAt:${string}` |
+	`idbfallback::${string}`
+
+// セッション毎に廃棄されるLocalStorage代替（embedなどで使用）
+const safeSessionStorage = new Map<Keys, string>();
 
 export const miLocalStorage = {
-	getItem: (key: Keys): string | null => window.localStorage.getItem(key),
-	setItem: (key: Keys, value: string): void => window.localStorage.setItem(key, value),
-	removeItem: (key: Keys): void => window.localStorage.removeItem(key),
+	getItem: (key: Keys): string | null => {
+		if (isEmbedPage()) {
+			return safeSessionStorage.get(key) ?? null;
+		}
+		return window.localStorage.getItem(key);
+	},
+	setItem: (key: Keys, value: string): void => {
+		if (isEmbedPage()) {
+			safeSessionStorage.set(key, value);
+		} else {
+			window.localStorage.setItem(key, value);
+		}
+	},
+	removeItem: (key: Keys): void => {
+		if (isEmbedPage()) {
+			safeSessionStorage.delete(key);
+		} else {
+			window.localStorage.removeItem(key);
+		}
+	},
 	getItemAsJson: (key: Keys): any | undefined => {
 		const item = miLocalStorage.getItem(key);
 		if (item === null) {
@@ -51,5 +73,12 @@ export const miLocalStorage = {
 		}
 		return JSON.parse(item);
 	},
-	setItemAsJson: (key: Keys, value: any): void => window.localStorage.setItem(key, JSON.stringify(value)),
+	setItemAsJson: (key: Keys, value: any): void => {
+		miLocalStorage.setItem(key, JSON.stringify(value));
+	},
 };
+
+if (isEmbedPage()) {
+	initEmbedPageLocalStorage();
+	if (_DEV_) console.warn('Using safeSessionStorage as localStorage alternative');
+}
diff --git a/packages/frontend/src/os.ts b/packages/frontend/src/os.ts
index f656a52371..c12c206f12 100644
--- a/packages/frontend/src/os.ts
+++ b/packages/frontend/src/os.ts
@@ -24,6 +24,7 @@ import MkContextMenu from '@/components/MkContextMenu.vue';
 import { MenuItem } from '@/types/menu.js';
 import copyToClipboard from '@/scripts/copy-to-clipboard.js';
 import { showMovedDialog } from '@/scripts/show-moved-dialog.js';
+import { isEmbedPage } from '@/scripts/embed-page.js';
 
 export const openingWindowsCount = ref(0);
 
@@ -172,6 +173,8 @@ export async function popup<T extends Component>(
 	events: ComponentEmit<T> = {} as ComponentEmit<T>,
 	disposeEvent?: keyof ComponentEmit<T>,
 ): Promise<{ dispose: () => void }> {
+	if (isEmbedPage()) return { dispose: () => {} };
+
 	markRaw(component);
 
 	const id = ++popupIdCount;
diff --git a/packages/frontend/src/pages/embed/index.vue b/packages/frontend/src/pages/embed/index.vue
new file mode 100644
index 0000000000..e4c7b9e910
--- /dev/null
+++ b/packages/frontend/src/pages/embed/index.vue
@@ -0,0 +1,13 @@
+<template>
+	<div>
+		$i: {{ JSON.stringify($i) }}
+	</div>
+</template>
+
+<script setup lang="ts">
+import { $i } from '@/account.js';
+</script>
+
+<style scoped>
+
+</style>
diff --git a/packages/frontend/src/router/definition.ts b/packages/frontend/src/router/definition.ts
index c12ae0fa57..66a38b45ee 100644
--- a/packages/frontend/src/router/definition.ts
+++ b/packages/frontend/src/router/definition.ts
@@ -555,6 +555,10 @@ const routes: RouteDef[] = [{
 	path: '/reversi/g/:gameId',
 	component: page(() => import('@/pages/reversi/game.vue')),
 	loginRequired: false,
+}, {
+	path: '/embed',
+	component: page(() => import('@/pages/embed/index.vue')),
+//	children: [],
 }, {
 	path: '/timeline',
 	component: page(() => import('@/pages/timeline.vue')),
diff --git a/packages/frontend/src/scripts/embed-page.ts b/packages/frontend/src/scripts/embed-page.ts
new file mode 100644
index 0000000000..f50cf98a74
--- /dev/null
+++ b/packages/frontend/src/scripts/embed-page.ts
@@ -0,0 +1,37 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and misskey-project
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+import { miLocalStorage } from "@/local-storage.js";
+import type { Keys } from "@/local-storage.js";
+
+export function isEmbedPage() {
+	return location.pathname.startsWith('/embed');
+}
+
+/**
+ * EmbedページではlocalStorageを使用できないようにしているが、
+ * 動作に必要な値はsafeSessionStorage（miLocalStorage内のやつ）に移動する
+ */
+export function initEmbedPageLocalStorage() {
+	if (!isEmbedPage()) {
+		return;
+	}
+
+	const keysToDuplicate: Keys[] = [
+		'v',
+		'lastVersion',
+		'instance',
+		'instanceCachedAt',
+		'lang',
+		'locale',
+		'localeVersion',
+	];
+
+	keysToDuplicate.forEach(key => {
+		const value = window.localStorage.getItem(key);
+		if (value && !miLocalStorage.getItem(key)) {
+			miLocalStorage.setItem(key, value);
+		}
+	});
+}
diff --git a/packages/frontend/src/scripts/idb-proxy.ts b/packages/frontend/src/scripts/idb-proxy.ts
index 6b511f2a5f..35cf4a885f 100644
--- a/packages/frontend/src/scripts/idb-proxy.ts
+++ b/packages/frontend/src/scripts/idb-proxy.ts
@@ -10,10 +10,12 @@ import {
 	set as iset,
 	del as idel,
 } from 'idb-keyval';
+import { isEmbedPage } from './embed-page.js';
+import { miLocalStorage } from '@/local-storage.js';
 
-const fallbackName = (key: string) => `idbfallback::${key}`;
+const PREFIX = 'idbfallback::';
 
-let idbAvailable = typeof window !== 'undefined' ? !!(window.indexedDB && window.indexedDB.open) : true;
+let idbAvailable = typeof window !== 'undefined' ? !!(window.indexedDB && typeof window.indexedDB.open === 'function' && !isEmbedPage()) : true;
 
 // iframe.contentWindow.indexedDB.deleteDatabase() がchromeのバグで使用できないため、indexedDBを無効化している。
 // バグが治って再度有効化するのであれば、cypressのコマンド内のコメントアウトを外すこと
@@ -38,15 +40,15 @@ if (idbAvailable) {
 
 export async function get(key: string) {
 	if (idbAvailable) return iget(key);
-	return JSON.parse(window.localStorage.getItem(fallbackName(key)));
+	return miLocalStorage.getItemAsJson(`${PREFIX}${key}`);
 }
 
 export async function set(key: string, val: any) {
 	if (idbAvailable) return iset(key, val);
-	return window.localStorage.setItem(fallbackName(key), JSON.stringify(val));
+	return miLocalStorage.setItemAsJson(`${PREFIX}${key}`, val);
 }
 
 export async function del(key: string) {
 	if (idbAvailable) return idel(key);
-	return window.localStorage.removeItem(fallbackName(key));
+	return miLocalStorage.removeItem(`${PREFIX}${key}`);
 }
diff --git a/packages/frontend/src/scripts/post-message.ts b/packages/frontend/src/scripts/post-message.ts
index 31a9ac1ad9..3adde6060c 100644
--- a/packages/frontend/src/scripts/post-message.ts
+++ b/packages/frontend/src/scripts/post-message.ts
@@ -5,6 +5,7 @@
 
 export const postMessageEventTypes = [
 	'misskey:shareForm:shareCompleted',
+	'misskey:embed:changeHeight',
 ] as const;
 
 export type PostMessageEventType = typeof postMessageEventTypes[number];
@@ -18,7 +19,7 @@ export type MiPostMessageEvent = {
  * 親フレームにイベントを送信
  */
 export function postMessageToParentWindow(type: PostMessageEventType, payload?: any): void {
-	window.postMessage({
+	window.parent.postMessage({
 		type,
 		payload,
 	}, '*');
diff --git a/packages/frontend/src/ui/minimum.vue b/packages/frontend/src/ui/minimum.vue
index db5eb19c20..9ab0b5d6b3 100644
--- a/packages/frontend/src/ui/minimum.vue
+++ b/packages/frontend/src/ui/minimum.vue
@@ -4,7 +4,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 -->
 
 <template>
-<div :class="$style.root">
+<div :class="isEmbed ? $style.rootForEmbedPage : $style.root">
 	<div style="container-type: inline-size;">
 		<RouterView/>
 	</div>
@@ -20,6 +20,12 @@ import { PageMetadata, provideMetadataReceiver, provideReactiveMetadata } from '
 import { instanceName } from '@/config.js';
 import { mainRouter } from '@/router/main.js';
 
+const props = withDefaults(defineProps<{
+	isEmbed?: boolean;
+}>(), {
+	isEmbed: false,
+});
+
 const isRoot = computed(() => mainRouter.currentRoute.value.name === 'index');
 
 const pageMetadata = ref<null | PageMetadata>(null);
@@ -38,7 +44,9 @@ provideMetadataReceiver((metadataGetter) => {
 });
 provideReactiveMetadata(pageMetadata);
 
-document.documentElement.style.overflowY = 'scroll';
+if (!props.isEmbed) {
+	document.documentElement.style.overflowY = 'scroll';
+}
 </script>
 
 <style lang="scss" module>
@@ -46,4 +54,8 @@ document.documentElement.style.overflowY = 'scroll';
 	min-height: 100dvh;
 	box-sizing: border-box;
 }
+
+.rootForEmbedPage {
+	box-sizing: border-box;
+}
 </style>