diff --git a/package.json b/package.json
index dd023c9..347a4fc 100644
--- a/package.json
+++ b/package.json
@@ -25,6 +25,7 @@
 	"dependencies": {
 		"@babel/preset-react": "^7.14.5",
 		"@reduxjs/toolkit": "^1.6.1",
+		"@types/insert-text-at-cursor": "^0.3.0",
 		"@types/koa-bodyparser": "^4.3.0",
 		"@types/koa-multer": "^1.0.0",
 		"@types/koa-send": "^4.1.3",
@@ -45,6 +46,7 @@
 		"fibers": "^5.0.0",
 		"i18next": "^20.6.1",
 		"i18next-browser-languagedetector": "^6.1.2",
+		"insert-text-at-cursor": "^0.3.0",
 		"json5-loader": "^4.0.1",
 		"koa": "^2.13.0",
 		"koa-bodyparser": "^4.3.0",
diff --git a/src/frontend/App.tsx b/src/frontend/App.tsx
index 3846ebe..2e96e98 100644
--- a/src/frontend/App.tsx
+++ b/src/frontend/App.tsx
@@ -1,6 +1,7 @@
 import React, { useState, useEffect, useCallback } from 'react';
 import { BrowserRouter, Link, Route, Switch, useLocation } from 'react-router-dom';
 import { Provider } from 'react-redux';
+import { useTranslation } from 'react-i18next';
 
 import { IndexPage } from './pages';
 import { RankingPage } from './pages/ranking';
@@ -46,6 +47,8 @@ const AppInner : React.VFC = () => {
 		};
 	}, [osTheme, setOsTheme]);
 
+	const {t} = useTranslation();
+
 	return (
 		<>
 			<div className="container">
@@ -57,7 +60,7 @@ const AppInner : React.VFC = () => {
 				</Switch>
 				<footer className="text-center pa-5">
 					<p>(C)2020-2021 Xeltica</p>
-					<p><Link to="/term">利用規約</Link></p>
+					<p><Link to="/term">{t('termsOfService')}</Link></p>
 				</footer>
 				<ModalComponent />
 			</div>
diff --git a/src/frontend/Modal.tsx b/src/frontend/Modal.tsx
index 98d1284..b84b395 100644
--- a/src/frontend/Modal.tsx
+++ b/src/frontend/Modal.tsx
@@ -73,7 +73,7 @@ export const ModalComponent: React.VFC = () => {
 	if (!shown || !modal) return null;
 
 	return (
-		<div className="modal" onClick={() => dispatch(hideModal())}>
+		<div className="modal fade" onClick={() => dispatch(hideModal())}>
 			<div className="fade up" onClick={(e) => e.stopPropagation()}>
 				{ ModalInner(modal) }
 			</div>
diff --git a/src/frontend/components/DeveloperInfo.tsx b/src/frontend/components/DeveloperInfo.tsx
index a81dd5e..8ee3ffb 100644
--- a/src/frontend/components/DeveloperInfo.tsx
+++ b/src/frontend/components/DeveloperInfo.tsx
@@ -1,10 +1,12 @@
 import React from 'react';
+import { useTranslation } from 'react-i18next';
 
 export const DeveloperInfo: React.VFC = () => {
+	const {t} = useTranslation();
 	return (
 		<>
-			<h1>開発者</h1>
-			<p>何か困ったことがあったら、以下のアカウントにメッセージを送ってください。</p>
+			<h1>{t('_developerInfo.title')}</h1>
+			<p>{t('_developerInfo.description')}</p>
 			<ul>
 				<li><a href="http://misskey.io/@ebi" target="_blank" rel="noopener noreferrer">@ebi@misskey.io</a></li>
 				<li><a href="http://groundpolis.app/@X" target="_blank" rel="noopener noreferrer">@X@groundpolis.app</a></li>
diff --git a/src/frontend/components/HashtagTimeline.tsx b/src/frontend/components/HashtagTimeline.tsx
index d5fc06e..8596cb7 100644
--- a/src/frontend/components/HashtagTimeline.tsx
+++ b/src/frontend/components/HashtagTimeline.tsx
@@ -1,14 +1,16 @@
 import React from 'react';
+import { useTranslation } from 'react-i18next';
 
 export type HashtagTimelineProps = {
 	hashtag: string;
 };
 
 export const HashtagTimeline: React.VFC<HashtagTimelineProps> = ({hashtag}) => {
+	const {t} = useTranslation();
 	return (
 		<>
-			<h1>タイムライン</h1>
-			<p>#{hashtag} タグを含む最新ノートを表示します。</p>
+			<h1>{t('_timeline.title')}</h1>
+			<p>{t('_timeline.description', { hashtag })}</p>
 			<p>WIP</p>
 		</>
 	);
diff --git a/src/frontend/components/Header.tsx b/src/frontend/components/Header.tsx
index 8bdbef6..618b7bb 100644
--- a/src/frontend/components/Header.tsx
+++ b/src/frontend/components/Header.tsx
@@ -8,19 +8,17 @@ export type HeaderProps = {
 	hasTopLink?: boolean;
 };
 
+const messageNumber = Math.floor(Math.random() * 6) + 1;
+
 export const Header: React.FC<HeaderProps> = ({hasTopLink, children}) => {
 	const { t } = useTranslation();
-
-	const message = React.useMemo(
-		() => welcomeMessage[Math.floor(Math.random() * welcomeMessage.length)] , []);
-
 	return (
-		<header className={'xarticle card shadow-4 mt-5 mb-3'}>
+		<header className={'xarticle card mt-5 mb-3'}>
 			<div className="body">
 				<h1 className="text-primary mb-0" style={{ fontSize: '2rem' }}>
 					{hasTopLink ? <Link to="/">{t('title')}</Link> : t('title')}
 				</h1>
-				<h2 className="text-dimmed ml-1">{message}</h2>
+				<h2 className="text-dimmed ml-1">{t(`_welcomeMessage.pattern${messageNumber}`)}</h2>
 				{children}
 			</div>
 		</header>
diff --git a/src/frontend/components/LoginForm.tsx b/src/frontend/components/LoginForm.tsx
index 9bdfdd5..5638e8c 100644
--- a/src/frontend/components/LoginForm.tsx
+++ b/src/frontend/components/LoginForm.tsx
@@ -1,18 +1,19 @@
 import React, { useState } from 'react';
+import { useTranslation } from 'react-i18next';
 
 export const LoginForm: React.VFC = () => {
 	const [host, setHost] = useState('');
+	const {t} = useTranslation();
 
 	return (
 		<nav>
 			<div>
-				<strong>インスタンスURL</strong>
+				<strong>{t('instanceUrl')}</strong>
 			</div>
 			<div className="hgroup">
 				<input
 					className="input-field"
 					type="text"
-					placeholder="例: misskey.io"
 					value={host}
 					onChange={(e) => setHost(e.target.value)}
 					required
@@ -23,7 +24,7 @@ export const LoginForm: React.VFC = () => {
 					disabled={!host}
 					onClick={() => location.href = `//${location.host}/login?host=${encodeURIComponent(host)}`}
 				>
-					ログイン
+					{t('login')}
 				</button>
 			</div>
 		</nav>
diff --git a/src/frontend/components/Ranking.tsx b/src/frontend/components/Ranking.tsx
index cc0de76..f8e25b1 100644
--- a/src/frontend/components/Ranking.tsx
+++ b/src/frontend/components/Ranking.tsx
@@ -1,4 +1,5 @@
 import React, { useEffect, useState } from 'react';
+import { useTranslation } from 'react-i18next';
 
 interface RankingResponse {
 	isCalculating: boolean;
@@ -21,6 +22,7 @@ export const Ranking: React.VFC<RankingProps> = ({limit}) => {
 	const [response, setResponse] = useState<RankingResponse | null>(null);
 	const [isFetching, setIsFetching] = useState(true);
 	const [isError, setIsError] = useState(false);
+	const {t} = useTranslation();
 
 	// APIコール
 	useEffect(() => {
@@ -39,27 +41,27 @@ export const Ranking: React.VFC<RankingProps> = ({limit}) => {
 
 	return (
 		isFetching ? (
-			<p className="text-dimmed">取得中…</p>
+			<p className="text-dimmed">{t('fetching')}</p>
 		) : isError ? (
-			<div className="alert bg-danger">取得エラー</div>
+			<div className="alert bg-danger">{t('failedToFetch')}</div>
 		) : response ? (
 			<>
-				<aside>登録者数：{response?.userCount}</aside>
+				<aside>{t('registeredUsersCount')}: {response?.userCount}</aside>
 				{response.isCalculating ? (
-					<p>現在算出中です。後ほどご確認ください！</p>
+					<p>{t('isCalculating')}</p>
 				) : (
-					<table className="table shadow-2 mt-1 fluid">
+					<table className="table mt-1 fluid">
 						<thead>
 							<tr>
-								<th>順位</th>
-								<th>名前</th>
-								<th>レート</th>
+								<th>{t('_missHai.order')}</th>
+								<th>{t('name')}</th>
+								<th>{t('_missHai.rating')}</th>
 							</tr>
 						</thead>
 						<tbody>
 							{response.ranking.map((r, i) => (
 								<tr key={i}>
-									<td>{i + 1}位</td>
+									<td>{i + 1}</td>
 									<td>
 										{r.username}@{r.host}
 									</td>
diff --git a/src/frontend/components/SessionDataPage.tsx b/src/frontend/components/SessionDataPage.tsx
index 32ff76d..2c894db 100644
--- a/src/frontend/components/SessionDataPage.tsx
+++ b/src/frontend/components/SessionDataPage.tsx
@@ -1,4 +1,5 @@
 import React, { useEffect } from 'react';
+import { useTranslation } from 'react-i18next';
 import { LOCALSTORAGE_KEY_TOKEN } from '../const';
 import { useGetScoreQuery, useGetSessionQuery } from '../services/session';
 import { Skeleton } from './Skeleton';
@@ -6,6 +7,7 @@ import { Skeleton } from './Skeleton';
 export const SessionDataPage: React.VFC = () => {
 	const session = useGetSessionQuery(undefined);
 	const score = useGetScoreQuery(undefined);
+	const {t} = useTranslation();
 
 	/**
 	 * Session APIのエラーハンドリング
@@ -30,20 +32,10 @@ export const SessionDataPage: React.VFC = () => {
 		<div className="fade">
 			{session.data && (
 				<section>
-					<p>
-						おかえりなさい、
-						<a
-							href={`https://${session.data.host}/@${session.data.username}`}
-							target="_blank"
-							rel="noreferrer noopener"
-						>
-							@{session.data.username}@{session.data.host}
-						</a>
-						さん。
-					</p>
+					<p>{t('welcomeBack', {acct: `@${session.data.username}@${session.data.host}`})}</p>
 					<p>
 						<strong>
-							みす廃レート:
+							{t('_missHai.rating')}:
 						</strong>
 						{session.data.rating}
 					</p>
@@ -51,28 +43,28 @@ export const SessionDataPage: React.VFC = () => {
 			)}
 			{score.data && (
 				<section>
-					<h2>みす廃データ</h2>
-					<table className="table fluid shadow-2" style={{border: 'none'}}>
+					<h2>{t('_missHai.data')}</h2>
+					<table className="table fluid">
 						<thead>
 							<tr>
-								<th>内容</th>
-								<th>スコア</th>
-								<th>前日比</th>
+								<th></th>
+								<th>{t('_missHai.dataScore')}</th>
+								<th>{t('_missHai.dataDelta')}</th>
 							</tr>
 						</thead>
 						<tbody>
 							<tr>
-								<td>ノート</td>
+								<td>{t('notes')}</td>
 								<td>{score.data.notesCount}</td>
 								<td>{score.data.notesDelta}</td>
 							</tr>
 							<tr>
-								<td>フォロー</td>
+								<td>{t('following')}</td>
 								<td>{score.data.followingCount}</td>
 								<td>{score.data.followingDelta}</td>
 							</tr>
 							<tr>
-								<td>フォロワー</td>
+								<td>{t('followers')}</td>
 								<td>{score.data.followersCount}</td>
 								<td>{score.data.followersDelta}</td>
 							</tr>
diff --git a/src/frontend/components/SettingPage.tsx b/src/frontend/components/SettingPage.tsx
index 82e12c8..83d5c9c 100644
--- a/src/frontend/components/SettingPage.tsx
+++ b/src/frontend/components/SettingPage.tsx
@@ -5,12 +5,13 @@ import { Visibility } from '../../common/types/visibility';
 import { useGetSessionQuery } from '../services/session';
 import { defaultTemplate } from '../../common/default-template';
 import { Card } from './Card';
-import { Theme } from '../misc/theme';
-import { API_ENDPOINT, LOCALSTORAGE_KEY_LANG, LOCALSTORAGE_KEY_TOKEN } from '../const';
+import { Theme, themes } from '../misc/theme';
+import { API_ENDPOINT, LOCALSTORAGE_KEY_TOKEN } from '../const';
 import { useDispatch } from 'react-redux';
 import { changeLang, changeTheme, showModal } from '../store/slices/screen';
 import { useSelector } from '../store';
 import { languageName } from '../langs';
+import { useTranslation } from 'react-i18next';
 
 type SettingDraftType = Partial<Pick<IUser,
 	| 'alertMode'
@@ -27,6 +28,7 @@ export const SettingPage: React.VFC = () => {
 	const dispatch = useDispatch();
 
 	const data = session.data;
+	const {t} = useTranslation();
 
 	const [draft, dispatchDraft] = useReducer<DraftReducer>((state, action) => {
 		return { ...state, ...action };
@@ -38,23 +40,8 @@ export const SettingPage: React.VFC = () => {
 		template: data?.template ?? null,
 	});
 
-	const themes: Array<{ theme: Theme, name: string }> = [
-		{
-			theme: 'light',
-			name: 'ライトテーマ'
-		},
-		{
-			theme: 'dark',
-			name: 'ダークテーマ'
-		},
-		{
-			theme: 'system',
-			name: 'システム設定に準じる'
-		},
-	];
-
 	const currentTheme = useSelector(state => state.screen.theme);
-	const currentLang = useSelector(state => state.screen.lang);
+	const currentLang = useSelector(state => state.screen.language);
 
 	const availableVisibilities: Visibility[] = [
 		'public',
@@ -150,7 +137,7 @@ export const SettingPage: React.VFC = () => {
 	) : (
 		<div className="vstack fade">
 			<Card bodyClassName="vstack">
-				<h1>アラート送信方法</h1>
+				<h1>{t('alertMode')}</h1>
 				<div>
 					{
 						alertModes.map((mode) => (
@@ -158,27 +145,27 @@ export const SettingPage: React.VFC = () => {
 								<input type="radio" checked={mode === draft.alertMode} onChange={() => {
 									updateSetting({ alertMode: mode });
 								}} />
-								<span>{mode}</span>
+								<span>{t(`_alertMode.${mode}`)}</span>
 							</label>
 						))
 					}
 					{draft.alertMode === 'notification' && (
 						<div className="alert bg-danger mt-2">
 							<i className="icon bi bi-exclamation-circle"></i>
-							「Misskey に通知」オプションは古いMisskeyでは動作しません。
+							{t('_alertMode.notificationWarning')}
 						</div>
 					)}
 				</div>
 				{ draft.alertMode === 'note' && (
 					<div>
-						<label htmlFor="visibility" className="input-field">公開範囲</label>
+						<label htmlFor="visibility" className="input-field">{t('visibility')}</label>
 						{
 							availableVisibilities.map((visibility) => (
 								<label key={visibility} className="input-check">
 									<input type="radio" checked={visibility === draft.visibility} onChange={() => {
 										updateSetting({ visibility });
 									}} />
-									<span>{visibility}</span>
+									<span>{t(`_visibility.${visibility}`)}</span>
 								</label>
 							))
 						}
@@ -186,26 +173,26 @@ export const SettingPage: React.VFC = () => {
 							<input type="checkbox" checked={draft.localOnly} onChange={(e) => {
 								updateSetting({ localOnly: e.target.checked });
 							}} />
-							<span>ローカル限定</span>
+							<span>{t('localOnly')}</span>
 						</label>
 					</div>
 				)}
 			</Card>
 			<Card bodyClassName="vstack">
-				<h1>表示設定</h1>
-				<h2>テーマ</h2>
+				<h1>{t('appearance')}</h1>
+				<h2>{t('theme')}</h2>
 				<div>
 					{
-						themes.map(({ theme, name }) => (
+						themes.map(theme => (
 							<label key={theme} className="input-check">
 								<input type="radio" value={theme} checked={theme === currentTheme} onChange={(e) => dispatch(changeTheme(e.target.value as Theme))} />
-								<span>{name}</span>
+								<span>{t(`_themes.${theme}`)}</span>
 							</label>
 						))
 					}
 				</div>
 
-				<h2>言語設定</h2>
+				<h2>{t('language')}</h2>
 				<select name="currentLang" className="input-field" value={currentLang} onChange={(e) => {
 					dispatch(changeLang(e.target.value));
 				}}>
@@ -218,16 +205,14 @@ export const SettingPage: React.VFC = () => {
 			</Card>
 
 			<Card bodyClassName="vstack">
-				<h1>テンプレート</h1>
-				<p>アラートの自動投稿をカスタマイズできます。</p>
+				<h1>{t('template')}</h1>
+				<p>{t('_template.description')}</p>
 				<textarea className="input-field" value={draft.template ?? defaultTemplate} placeholder={defaultTemplate} style={{height: 228}} onChange={(e) => {
 					dispatchDraft({ template: e.target.value });
 				}} />
-				<small className="text-dimmed">
-					ハッシュタグ #misshaialert は、テンプレートに関わらず自動付与されます。
-				</small>
+				<small className="text-dimmed">{t('_template.description2')}</small>
 				<details>
-					<summary>ヘルプ</summary>
+					<summary>{t('help')}</summary>
 					<ul className="fade">
 						<li><code>{'{'}notesCount{'}'}</code>といった形式のテキストは変数として扱われ、これを含めると投稿時に自動的に値が埋め込まれます。</li>
 					</ul>
@@ -236,26 +221,20 @@ export const SettingPage: React.VFC = () => {
 					<button className="btn danger" onClick={() => dispatchDraft({ template: null })}>初期値に戻す</button>
 					<button className="btn primary" onClick={() => {
 						updateSettingWithDialog({ template: draft.template === '' ? null : draft.template });
-					}}>保存</button>
+					}}>{t('save')}</button>
 				</div>
 			</Card>
 			<Card bodyClassName="vstack">
-				<button className="btn block" onClick={onClickSendAlert}>アラートをテスト送信する</button>
-				<p className="text-dimmed">
-					現在の設定を用いて、アラート送信をテストします。
-				</p>
+				<button className="btn block" onClick={onClickSendAlert}>{t('sendAlert')}</button>
+				<p className="text-dimmed">{t('sendAlertDescription')}</p>
 			</Card>
 			<Card bodyClassName="vstack">
-				<button className="btn block" onClick={onClickLogout}>ログアウトする</button>
-				<p className="text-dimmed">
-					ログアウトしても、アラートは送信されます。
-				</p>
+				<button className="btn block" onClick={onClickLogout}>{t('logout')}</button>
+				<p className="text-dimmed">{t('logoutDescription')}</p>
 			</Card>
 			<Card bodyClassName="vstack">
-				<button className="btn danger block" onClick={onClickDeleteAccount}>アカウント連携を解除する</button>
-				<p className="text-dimmed">
-					Misskeyとの連携設定を含むみす廃アラートのアカウントを削除します。
-				</p>
+				<button className="btn danger block" onClick={onClickDeleteAccount}>{t('deleteAccount')}</button>
+				<p className="text-dimmed">{t('deleteAccountDescription')}</p>
 			</Card>
 		</div>
 	);
diff --git a/src/frontend/langs/en_US.json5 b/src/frontend/langs/en_US.json5
index a2f2e62..3087fed 100644
--- a/src/frontend/langs/en_US.json5
+++ b/src/frontend/langs/en_US.json5
@@ -1,5 +1,99 @@
 {
 	translation: {
-		title: "Misskey Alert",
-	}
+		title: "Misskey Tools",
+		description1: "Misskeyは楽しいものです。気がついたら1日中入り浸っていることも多いでしょう。",
+		description2: "さあ、今すぐMisskey Toolsをインストールして、あなたの活動を把握しよう。",
+		notes: "Notes",
+		following: "Following",
+		followers: "Followers",
+		welcomeBack: "Welcome back, {{acct}}.",
+		alertMode: "How to Send Alerts",
+		visibility: "Visibility",
+		appearance: "Appearance",
+		template: "Template",
+		sendAlert: "Test your alert",
+		sendAlertDescription: "Send your alert with current settings to test.",
+		logout: "Log Out",
+		logoutDescription: "If you log out, alerts will be sent.",
+		deleteAccount: "Deactivate account integration",
+		deleteAccountDescription: "Delete your Misskey Tools account. This will deactivate integration with Misskey.",
+		instanceUrl: "Instance URL",
+		login: "Login",
+		localOnly: "Local Only",
+		remoteFollowersOnly: "Remote Followers and Local Only",
+		help: "Help",
+		save: "Save",
+		theme: "Theme",
+		language: "Language",
+		fetching: "Fetching...",
+		failedToFetch: "Failed to fetch",
+		registeredUsersCount: "Users",
+		isCalculating: "It is being calculated now. Please check back later!",
+		ok: "OK",
+		yes: "Yes",
+		no: "No",
+		termsOfService: "Terms of Service",
+		name: "Name",
+		_welcomeMessage: {
+			pattern1: "Overnoting Misskey?",
+			pattern2: "Overusing Misskey?",
+			pattern3: "How many notes did you write today?",
+			pattern4: "Do you really think you're lite-misskist?",
+			pattern5: "Misskey is my breathing!",
+			pattern6: "I'm Misskey freak!",
+		},
+		_sendAlertDialog: {
+			title: "Are you sure you want to send the alert for testing?",
+			message: "Send an alert with the current settings. Be sure to check whether you saved the settings before executing.",
+			success: "Alert sent.",
+			error: "Failed to send alert.",
+		},
+		_nav: {
+			data: "Data",
+			ranking: "Ranking",
+			settings: "Settings",
+		},
+		_missHai: {
+			ranking: "Miss-hai Ranking",
+			rankingDescription1: "ユーザーの「みす廃レート」を算出し、高い順にランキング表示しています。みす廃レートは、次のような条件で算出されます。",
+			rankingFormula: "(ノート数) / (アカウント登録からの経過日数)",
+			rankingDescription2: "廃人を極めるか、ノート数を控えるか、全てあなた次第！",
+			showAll: "Show All",
+			data: "Miss-hai Data",
+			dataBody: "",
+			dataScore: "Score",
+			dataDelta: "Difference",
+			rating: "Rating",
+			order: "Order",
+		},
+		_developerInfo: {
+			title: "Developer",
+			description: "If you want supports, send messages to the below accounts.",
+		},
+		_timeline: {
+			title: "Timeline",
+			description: "Shows latest notes including {{hashtag}} tags.",
+		},
+		_alertMode: {
+			note: "Automatic Note",
+			notification: "Notify to your account (Default)",
+			nothing: "Do Nothing",
+			notificationWarning: "'Notify to your account' option will not be work on legacy versions of Misskey.",
+		},
+		_visibility: {
+			public: "Public",
+			home: "Home",
+			followers: "Followers",
+			users: "Logged-in Users",
+		},
+		_themes: {
+			light: "Light",
+			dark: "Dark",
+			system: "Follows System Preferences",
+		},
+		_template: {
+			description: "アラートの自動投稿をカスタマイズできます。",
+			description2: "ハッシュタグ #misshaialert は、テンプレートに関わらず自動付与されます。",
+		},
+	},
 }
diff --git a/src/frontend/langs/ja_JP.json5 b/src/frontend/langs/ja_JP.json5
index d69ddca..b443c55 100644
--- a/src/frontend/langs/ja_JP.json5
+++ b/src/frontend/langs/ja_JP.json5
@@ -1,5 +1,99 @@
 {
 	translation: {
-		title: "みす廃アラート",
-	}
+		title: "Misskey Tools",
+		description1: "Misskeyは楽しいものです。気がついたら1日中入り浸っていることも多いでしょう。",
+		description2: "さあ、今すぐMisskey Toolsをインストールして、あなたの活動を把握しよう。",
+		notes: "ノート",
+		following: "フォロー",
+		followers: "フォロワー",
+		welcomeBack: "おかえりなさい、{{acct}}さん。",
+		alertMode: "アラート送信方法",
+		visibility: "公開範囲",
+		appearance: "表示設定",
+		template: "テンプレート",
+		sendAlert: "アラートをテスト送信する",
+		sendAlertDescription: "現在の設定を用いて、アラート送信をテストします。",
+		logout: "ログアウトする",
+		logoutDescription: "ログアウトしても、アラートは送信されます。",
+		deleteAccount: "アカウント連携を解除する",
+		deleteAccountDescription: "Misskey Toolsのアカウントを削除します。これにより、Misskeyとの連携設定も解除されます。",
+		instanceUrl: "インスタンスURL",
+		login: "ログイン",
+		localOnly: "ローカルのみ",
+		remoteFollowersOnly: "リモートフォロワーとローカル",
+		help: "ヘルプ",
+		save: "保存",
+		theme: "テーマ",
+		language: "言語",
+		fetching: "取得中……",
+		failedToFetch: "取得に失敗しました",
+		registeredUsersCount: "登録者数",
+		isCalculating: "現在算出中です。後ほどご確認ください！",
+		ok: "OK",
+		yes: "はい",
+		no: "いいえ",
+		termsOfService: "利用規約",
+		name: "名前",
+		_welcomeMessage: {
+			'pattern1': 'ついついノートしすぎていませんか？',
+			'pattern2': 'Misskey, しすぎていませんか？',
+			'pattern3': '今日、何ノート書いた？',
+			'pattern4': '10000 ノートは初心者、そう思っていませんか？',
+			'pattern5': '息するように Misskey、そんなあなたへ。',
+			'pattern6': 'あなたは真の Misskey 廃人ですか？',
+		},
+		_sendAlertDialog: {
+			title: "アラートをテスト送信しますか？",
+			message: "現在の設定でアラートを送信します。設定が保存済みであるかどうか、実行前に必ずご確認ください。",
+			success: "送信しました。",
+			error: "送信に失敗しました。",
+		},
+		_nav: {
+			data: "データ",
+			ranking: "ランキング",
+			settings: "設定",
+		},
+		_missHai: {
+			ranking: "ミス廃ランキング",
+			rankingDescription1: "ユーザーの「みす廃レート」を算出し、高い順にランキング表示しています。みす廃レートは、次のような条件で算出されます。",
+			rankingFormula: "(ノート数) / (アカウント登録からの経過日数)",
+			rankingDescription2: "廃人を極めるか、ノート数を控えるか、全てあなた次第！",
+			showAll: "全員分見る",
+			data: "みす廃データ",
+			dataBody: "内容",
+			dataScore: "スコア",
+			dataDelta: "前日比",
+			rating: "レート",
+			order: "順位",
+		},
+		_developerInfo: {
+			title: "開発者",
+			description: "何か困ったことがあったら、以下のアカウントにメッセージを送ってください。",
+		},
+		_timeline: {
+			title: "タイムライン",
+			description: "{{hashtag}} タグを含む最新ノートを表示します。",
+		},
+		_alertMode: {
+			note: "自動的にノートを投稿",
+			notification: "Misskeyに通知(標準)",
+			nothing: "通知しない",
+			notificationWarning: "「Misskey に通知」オプションは古いMisskeyでは動作しません。",
+		},
+		_visibility: {
+			public: "パブリック",
+			home: "ホーム",
+			followers: "フォロワー",
+			users: "ログインユーザー",
+		},
+		_themes: {
+			light: "ライトテーマ",
+			dark: "ダークテーマ",
+			system: "システム設定に準じる",
+		},
+		_template: {
+			description: "アラートの自動投稿をカスタマイズできます。",
+			description2: "ハッシュタグ #misshaialert は、テンプレートに関わらず自動付与されます。",
+		},
+	},
 }
diff --git a/src/frontend/misc/theme.ts b/src/frontend/misc/theme.ts
index 24ca003..b05514f 100644
--- a/src/frontend/misc/theme.ts
+++ b/src/frontend/misc/theme.ts
@@ -1,3 +1,13 @@
-export type Theme = ActualTheme | 'system';
+export const actualThemes = [
+	'light',
+	'dark',
+] as const;
 
-export type ActualTheme = 'light' | 'dark';
+export const themes = [
+	...actualThemes,
+	'system',
+] as const;
+
+export type Theme = typeof themes[number];
+
+export type ActualTheme = typeof actualThemes[number];
diff --git a/src/frontend/pages/index.session.tsx b/src/frontend/pages/index.session.tsx
index 1241fcc..0ff372f 100644
--- a/src/frontend/pages/index.session.tsx
+++ b/src/frontend/pages/index.session.tsx
@@ -5,15 +5,17 @@ import { SessionDataPage } from '../components/SessionDataPage';
 import { Ranking } from '../components/Ranking';
 import { Tab, TabItem } from '../components/Tab';
 import { SettingPage } from '../components/SettingPage';
+import { useTranslation } from 'react-i18next';
 
 export const IndexSessionPage: React.VFC = () => {
 	const [selectedTab, setSelectedTab] = useState<number>(0);
+	const {t, i18n} = useTranslation();
 
 	const items = useMemo<TabItem[]>(() => ([
-		{ label: 'データ' },
-		{ label: 'ランキング' },
-		{ label: '設定' },
-	]), []);
+		{ label: t('_nav.data') },
+		{ label: t('_nav.ranking') },
+		{ label: t('_nav.settings') },
+	]), [i18n.language]);
 
 	const component = useMemo(() => {
 		switch (selectedTab) {
diff --git a/src/frontend/pages/index.welcome.tsx b/src/frontend/pages/index.welcome.tsx
index 0075336..f9a61b3 100644
--- a/src/frontend/pages/index.welcome.tsx
+++ b/src/frontend/pages/index.welcome.tsx
@@ -1,5 +1,6 @@
 import React  from 'react';
 import { Link } from 'react-router-dom';
+import { useTranslation } from 'react-i18next';
 
 import { Ranking } from '../components/Ranking';
 import { LoginForm } from '../components/LoginForm';
@@ -8,20 +9,22 @@ import { HashtagTimeline } from '../components/HashtagTimeline';
 import { Header } from '../components/Header';
 
 export const IndexWelcomePage: React.VFC = () => {
+	const {t} = useTranslation();
+
 	return (
 		<>
 			<Header>
 				<article className="mt-4">
-					<p>Misskeyは楽しいものです。気がついたら1日中入り浸っていることも多いでしょう。</p>
-					<p>さあ、今すぐみす廃アラートをインストールして、あなたの活動を把握しよう。</p>
+					<p>{t('description1')}</p>
+					<p>{t('description2')}</p>
 				</article>
 				<LoginForm />
 			</Header>
 			<article className="xarticle card ghost">
 				<div className="body">
-					<h1 className="mb-1">みす廃ランキング</h1>
+					<h1 className="mb-1">{t('_missHai.ranking')}</h1>
 					<Ranking limit={10} />
-					<Link to="/ranking">全員分見る</Link>
+					<Link to="/ranking">{t('_missHai.showAll')}</Link>
 				</div>
 			</article>
 			<article className="xarticle mt-4 row">
diff --git a/src/frontend/pages/ranking.tsx b/src/frontend/pages/ranking.tsx
index 9d3b375..4ece520 100644
--- a/src/frontend/pages/ranking.tsx
+++ b/src/frontend/pages/ranking.tsx
@@ -1,18 +1,18 @@
 import React  from 'react';
+import { useTranslation } from 'react-i18next';
 import { Ranking } from '../components/Ranking';
 
 
 export const RankingPage: React.VFC = () => {
+	const {t} = useTranslation();
+
 	return (
 		<article className="xarticle">
-			<h2>みす廃ランキング</h2>
+			<h2>{t('_missHai.ranking')}</h2>
 			<section>
-				<p>
-					ユーザーの「みす廃レート」を算出し、高い順にランキング表示しています。
-					みす廃レートは、次のような条件で算出されます。
-				</p>
-				<p><strong>(ノート数) / (アカウント登録からの経過日数)</strong></p>
-				<p>廃人を極めるか、ノート数を控えるか、全てあなた次第！</p>
+				<p>{t('_missHai.rankingDescription1')}</p>
+				<p><strong>{t('_missHai.rankingFormula')}</strong></p>
+				<p>{t('_missHai.rankingDescription2')}</p>
 			</section>
 			<section className="pt-2">
 				<Ranking />
diff --git a/src/frontend/pages/term.tsx b/src/frontend/pages/term.tsx
index fe30655..ddeec9b 100644
--- a/src/frontend/pages/term.tsx
+++ b/src/frontend/pages/term.tsx
@@ -1,6 +1,7 @@
 import React  from 'react';
 
 export const TermPage: React.VFC = () => {
+	// TODO: 外部サイトに誘導する
 	return (
 		<article className="xarticle">
 			<h2>利用規約</h2>
diff --git a/src/frontend/style.scss b/src/frontend/style.scss
index 1f9f633..997ec20 100644
--- a/src/frontend/style.scss
+++ b/src/frontend/style.scss
@@ -71,8 +71,10 @@ small {
     z-index: 40000;
 }
 
-.dark .card.dialog {
-    background: var(--tone-2);
+.card.dialog {
+    .dark & {
+        background: var(--tone-2);
+    }
     min-width: min(100vw, 320px);
     max-width: min(100vw, 600px);
 }
\ No newline at end of file
diff --git a/yarn.lock b/yarn.lock
index 09944e9..2a09f7d 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -411,6 +411,11 @@
   resolved "https://registry.yarnpkg.com/@types/http-errors/-/http-errors-1.8.1.tgz#e81ad28a60bee0328c6d2384e029aec626f1ae67"
   integrity sha512-e+2rjEwK6KDaNOm5Aa9wNGgyS9oSZU/4pfSMMPYNOfjvFI0WVXm29+ITRFr6aKDvvKo7uU1jV68MW4ScsfDi7Q==
 
+"@types/insert-text-at-cursor@^0.3.0":
+  version "0.3.0"
+  resolved "https://registry.yarnpkg.com/@types/insert-text-at-cursor/-/insert-text-at-cursor-0.3.0.tgz#c7fafad758e26cd7f6bd82c46bf3601fec7afc3e"
+  integrity sha512-58a+1l6hz5DQ25NjODvZEYmJUWA1ALbUxcf/GHjMfh92r41lZkI6buNN0NwxIvJQDkTFNqL73G2Fduu5ctHVhA==
+
 "@types/json-schema@*", "@types/json-schema@^7.0.7", "@types/json-schema@^7.0.8":
   version "7.0.9"
   resolved "https://registry.yarnpkg.com/@types/json-schema/-/json-schema-7.0.9.tgz#97edc9037ea0c38585320b28964dde3b39e4660d"
@@ -2703,6 +2708,11 @@ ini@^1.3.4, ini@~1.3.0:
   resolved "https://registry.yarnpkg.com/ini/-/ini-1.3.8.tgz#a29da425b48806f34767a4efce397269af28432c"
   integrity sha512-JV/yugV2uzW5iMRSiZAyDtQd+nxtUnjeLt0acNdw98kKLrvuRVyB80tsREOE7yvGVgalhZ6RNXCmEHkUKBKxew==
 
+insert-text-at-cursor@^0.3.0:
+  version "0.3.0"
+  resolved "https://registry.yarnpkg.com/insert-text-at-cursor/-/insert-text-at-cursor-0.3.0.tgz#1819607680ec1570618347c4cd475e791faa25da"
+  integrity sha512-/nPtyeX9xPUvxZf+r0518B7uqNKlP+LqNJqSiXFEaa2T71rWIwTVXGH7hB9xO/EVdwa5/pWlFCPwShOW81XIxQ==
+
 internal-slot@^1.0.3:
   version "1.0.3"
   resolved "https://registry.yarnpkg.com/internal-slot/-/internal-slot-1.0.3.tgz#7347e307deeea2faac2ac6205d4bc7d34967f59c"