diff --git a/apps/vscode-extension/package.json b/apps/vscode-extension/package.json
index 486fd36..cb51b0d 100644
--- a/apps/vscode-extension/package.json
+++ b/apps/vscode-extension/package.json
@@ -24,7 +24,7 @@
     "commands": [
       {
         "command": "extension.showWebview",
-        "title": "AtCoder Helper（编辑器）"
+        "title": "AtCoder Helper (Editor)"
       },
       {
         "command": "extension.setDeeplApiKey",
diff --git a/apps/vscode-extension/package.nls.zh-cn.json b/apps/vscode-extension/package.nls.zh-cn.json
new file mode 100644
index 0000000..367f62e
--- /dev/null
+++ b/apps/vscode-extension/package.nls.zh-cn.json
@@ -0,0 +1,3 @@
+{
+  "extension.showWebview": "AtCoder Helper（编辑器）"
+}
diff --git a/apps/vscode-extension/src/extension.ts b/apps/vscode-extension/src/extension.ts
index e7bdbe2..01809c9 100644
--- a/apps/vscode-extension/src/extension.ts
+++ b/apps/vscode-extension/src/extension.ts
@@ -5,6 +5,7 @@ import { runCommand } from "./tools/command";
 import { IncomingMessage } from "./tools/types";
 import { getWebviewContent } from "./tools/webview";
 import { AtCoderViewProvider } from "./viewProvider";
+import { init, t } from "./tools/i18n";
 
 let sidebarViewProvider: AtCoderViewProvider | undefined;
 
@@ -39,27 +40,27 @@ export async function pullSubmitStatu(contest: string, taskName: string, send: (
       send({ type: "statusUpdate", statuses: Object.fromEntries(statusMap) });
       const status = statusMap.get(taskName);
       if (status && judgeStatus.has(status)) {
-        send({ type: "update", text: `评测结果: ${status}` });
+        send({ type: "update", text: t("ext.judgeResult", { status }) });
         return;
       }
     } catch {
       //单次轮询失败,直接下一次
     }
   }
-  send({ type: "update", text: "评测超时，请稍后手动刷新查看结果" });
+  send({ type: "update", text: t("ext.judgeTimeout") });
 }
 
 function registerSetDeeplApiKey(context: vscode.ExtensionContext) {
   return vscode.commands.registerCommand("extension.setDeeplApiKey", async () => {
     const key = await vscode.window.showInputBox({
-      prompt: "请输入 DeepL API Key",
+      prompt: t("ext.promptDeeplKey"),
       password: true,
-      placeHolder: "例如 xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx:fx",
+      placeHolder: t("ext.placeholderDeeplKey"),
       ignoreFocusOut: true,
     });
     if (key?.trim()) {
       await context.secrets.store("deeplApiKey", key.trim());
-      vscode.window.showInformationMessage("DeepL API Key 已保存");
+      vscode.window.showInformationMessage(t("ext.deeplKeySaved"));
     }
   });
 }
@@ -67,9 +68,9 @@ function registerSetDeeplApiKey(context: vscode.ExtensionContext) {
 function registerSetAtCoderCookie(context: vscode.ExtensionContext) {
   return vscode.commands.registerCommand("extension.setAtCoderCookie", async () => {
     const cookie = await vscode.window.showInputBox({
-      prompt: "粘贴 AtCoder 的 Cookie（仅需 REVEL_SESSION）",
+      prompt: t("ext.promptCookie"),
       password: true,
-      placeHolder: "REVEL_SESSION=abcdef1234567890abcdef1234567890",
+      placeHolder: t("ext.placeholderCookie"),
       ignoreFocusOut: true,
     });
     if (!cookie?.trim()) return;
@@ -77,23 +78,23 @@ function registerSetAtCoderCookie(context: vscode.ExtensionContext) {
     if (!trimmed.startsWith("REVEL_SESSION=")) {
       const fix = `REVEL_SESSION=${trimmed}`;
       const choice = await vscode.window.showWarningMessage(
-        `Cookie 格式似乎不正确，是否添加 REVEL_SESSION= 前缀？`,
+        t("ext.cookieFormatWarn"),
         { modal: false },
-        "自动修复",
-        "取消"
+        t("ext.autoFix"),
+        t("ext.cancel")
       );
-      if (choice === "自动修复") {
+      if (choice === t("ext.autoFix")) {
         await context.secrets.store("atcoderCookie", fix);
         setSessionCookie(fix);
         notifyCookieChanged(true);
-        vscode.window.showInformationMessage("AtCoder Cookie 已保存并自动修复格式");
+        vscode.window.showInformationMessage(t("ext.cookieSavedFixed"));
       }
       return;
     }
     await context.secrets.store("atcoderCookie", trimmed);
     setSessionCookie(trimmed);
     notifyCookieChanged(true);
-    vscode.window.showInformationMessage("AtCoder Cookie 已保存");
+    vscode.window.showInformationMessage(t("ext.cookieSaved"));
   });
 }
 
@@ -168,7 +169,7 @@ export function openContestPanel(context: vscode.ExtensionContext, contest: stri
 export function openSubmissionPanel(context: vscode.ExtensionContext, contest: string, id: string) {
   const panel = vscode.window.createWebviewPanel(
     "atcoderSubmission",
-    `提交 ${id} - ${contest}`,
+    t("ext.submissionPanelTitle", { id, contest }),
     vscode.ViewColumn.One,
     {
       enableScripts: true,
@@ -201,6 +202,7 @@ export function openSubmissionPanel(context: vscode.ExtensionContext, contest: s
 
 export async function activate(context: vscode.ExtensionContext) {
   log.info("Extension is now active!");
+  init(vscode.env.language);
 
   setStaleCookieHandler(() => {
     // vscode.window.showWarningMessage(
diff --git a/apps/vscode-extension/src/tools/SignUpContest.ts b/apps/vscode-extension/src/tools/SignUpContest.ts
index 5d702d3..bee85ff 100644
--- a/apps/vscode-extension/src/tools/SignUpContest.ts
+++ b/apps/vscode-extension/src/tools/SignUpContest.ts
@@ -1,4 +1,5 @@
 import { fetchText, fetchTextPost, CfError, LoginRequiredError, ProxyError } from "./fetch";
+import { t } from "./i18n";
 
 export interface ContestPage {
     contest: string;
@@ -113,20 +114,20 @@ function buildFormBody(fields: FormField[]): string {
 
 function parseRegistrationResult(html: string): RegistrationResult {
     const isSigned = /Unregister|registered/i.test(html);
-    if (isSigned) return { success: true, message: "报名成功！" };
+    if (isSigned) return { success: true, message: t("register.success") };
     const successMatch = html.match(
         /<div[^>]*class="[^"]*alert-success[^"]*"[^>]*>([\s\S]*?)<\/div>/i
     );
     if (successMatch) {
         const msg = successMatch[1].replace(/<[^>]+>/g, "").trim();
-        return { success: true, message: msg || "报名成功！" };
+        return { success: true, message: msg || t("register.success") };
     }
     const errMatch = html.match(
         /<div[^>]*class="[^"]*(?:alert-danger|alert-error)[^"]*"[^>]*>([\s\S]*?)<\/div>/i
     );
     if (errMatch) {
         const msg = errMatch[1].replace(/<[^>]+>/g, "").trim();
-        return { success: false, message: msg || "报名失败" };
+        return { success: false, message: msg || t("register.failed") };
     }
     return { success: false, message: "" };
 }
@@ -151,7 +152,7 @@ async function completeRatedRegistration(
         `<form[^>]*action="[^"]*${contest}\\/rated_register"[^>]*>([\\s\\S]*?)<\\/form>`,
         "i"
     );
-    const fallback: RegistrationResult = { success: false, message: "报名失败，请检查 Cookie 是否有效" };
+    const fallback: RegistrationResult = { success: false, message: t("register.failedBadCookie") };
     const step2Form = stepHtml.match(now)?.[1];
     if (!step2Form) {
         const result = parseRegistrationResult(stepHtml);
@@ -185,7 +186,7 @@ async function registerFormBased(contest: string, formHtml: string, rated: boole
         if (result.message) return result;
         return {
             success: false,
-            message: "报名未成功：注册页返回校验结果，请确认表单必填信息（如姓名、邮箱、居住地等）填写完整",
+            message: t("register.formIncomplete"),
         };
     }
     return await completeRatedRegistration(contest, responseHtml, rated);
@@ -196,11 +197,11 @@ export async function signedUpContest(contest: string, csrfToken: string, rated?
     try {
         const registerHtml = await fetchText(registerUrl);
         if (/Unregister|already registered/i.test(registerHtml)) {
-            return { success: true, message: "已报名" };
+            return { success: true, message: t("register.alreadyDone") };
         }
         const formHtml = extractFormHtml(registerHtml, contest);
         if (!formHtml) {
-            return { success: false, message: "报名已截止或无法获取报名信息" };
+            return { success: false, message: t("register.closed") };
         }
         const freshCsrfMatch = formHtml.match(/name="csrf_token"[^>]*value="([^"]*)"/i);
         const freshCsrf = freshCsrfMatch ? freshCsrfMatch[1] : csrfToken;
@@ -212,6 +213,6 @@ export async function signedUpContest(contest: string, csrfToken: string, rated?
         if (error instanceof CfError || error instanceof LoginRequiredError || error instanceof ProxyError) {
             throw error;
         }
-        return { success: false, message: error instanceof Error ? error.message : "报名请求失败" };
+        return { success: false, message: error instanceof Error ? error.message : t("register.requestFailed") };
     }
 }
\ No newline at end of file
diff --git a/apps/vscode-extension/src/tools/command.ts b/apps/vscode-extension/src/tools/command.ts
index 6f52a07..511533c 100644
--- a/apps/vscode-extension/src/tools/command.ts
+++ b/apps/vscode-extension/src/tools/command.ts
@@ -2,6 +2,7 @@ import * as vscode from "vscode";
 import { copyMarkdown } from "./copy";
 import { IncomingMessage } from "./types";
 import { openContestPanel, openSubmissionPanel } from "../extension"
+import { t } from "./i18n";
 import {
   handleContestLoad,
   handleProblemLoad,
@@ -32,7 +33,7 @@ export async function runCommand(message: IncomingMessage, context: vscode.Exten
   else if (problemCommands.has(message.command!)) await runProblem(message, context, sendToWebview);
   else if (submitCommands.has(message.command!)) await runSubmit(message, context, sendToWebview);
   else if (contestCommands.has(message.command!)) await runContest(message, context, sendToWebview);
-  else throw new Error("unknown command");
+  else throw new Error(t("cmd.unknown"));
 }
 
 async function runContest(command: IncomingMessage, context: vscode.ExtensionContext, sendToWebview: (payload: Record<string, unknown>) => void,): Promise<boolean> {
@@ -89,7 +90,7 @@ async function runProblem(command: IncomingMessage, context: vscode.ExtensionCon
     case "copyMarkdown":
       if (command.problem) {
         await vscode.env.clipboard.writeText(copyMarkdown(command.problem));
-        sendToWebview({ type: "update", text: "已复制到剪贴板" });
+        sendToWebview({ type: "update", text: t("cmd.copied") });
       }
       return true;
     case "alert":
@@ -127,7 +128,7 @@ async function runDeepL(command: IncomingMessage, context: vscode.ExtensionConte
     case "setApiKey":
       if (command.text?.trim()) {
         await context.secrets.store("deeplApiKey", command.text.trim());
-        vscode.window.showInformationMessage("DeepL API Key 已保存");
+        vscode.window.showInformationMessage(t("ext.deeplKeySaved"));
       }
       return true;
     default:
diff --git a/apps/vscode-extension/src/tools/copy.ts b/apps/vscode-extension/src/tools/copy.ts
index 492b36c..48e1d2e 100644
--- a/apps/vscode-extension/src/tools/copy.ts
+++ b/apps/vscode-extension/src/tools/copy.ts
@@ -1,4 +1,5 @@
 import { AtCoderProblem } from "../atcoder";
+import { t } from "./i18n";
 
 function decodeEntities(text: string): string {
     return text
@@ -57,36 +58,36 @@ export function copyMarkdown(problem: AtCoderProblem): string {
     parts.push("");
 
     if (problem.statement) {
-        parts.push("### 题目描述");
+        parts.push(t("md.statement"));
         parts.push(htmlToText(problem.statement));
         parts.push("");
     }
 
     if (problem.constraints) {
-        parts.push("### 约束");
+        parts.push(t("md.constraints"));
         parts.push(htmlToText(problem.constraints));
         parts.push("");
     }
 
     if (problem.inputFormat) {
-        parts.push("### 输入格式");
+        parts.push(t("md.inputFormat"));
         parts.push(htmlToText(problem.inputFormat));
         parts.push("");
     }
 
     if (problem.outputFormat) {
-        parts.push("### 输出格式");
+        parts.push(t("md.outputFormat"));
         parts.push(htmlToText(problem.outputFormat));
         parts.push("");
     }
 
     if (problem.samples && problem.samples.length > 0) {
         for (const sample of problem.samples) {
-            parts.push(`### 样例 ${sample.index}`);
-            parts.push("输入");
+            parts.push(t("md.sample", { index: sample.index }));
+            parts.push(t("md.inputLabel"));
             parts.push("```\n" + sample.input + "\n```");
             parts.push("");
-            parts.push("输出");
+            parts.push(t("md.outputLabel"));
             parts.push("```\n" + sample.output + "\n```");
             parts.push("");
         }
diff --git a/apps/vscode-extension/src/tools/cph.ts b/apps/vscode-extension/src/tools/cph.ts
index 930fc32..7a8eefc 100644
--- a/apps/vscode-extension/src/tools/cph.ts
+++ b/apps/vscode-extension/src/tools/cph.ts
@@ -1,5 +1,6 @@
 import * as http from "http";
 import { AtCoderProblem } from "../atcoder";
+import { t } from "./i18n";
 
 export interface CphTestCase {
     input: string;
@@ -21,10 +22,7 @@ export interface CphProblem {
 
 export class CphNotRunningError extends Error {
     constructor() {
-        super(
-            "未检测到 CPH 插件（localhost:27121 无响应）。\n" +
-            "请安装并启用 Competitive Programming Helper 扩展后重试。"
-        );
+        super(t("cph.notRunning"));
         this.name = "CphNotRunningError";
     }
 }
@@ -66,7 +64,7 @@ export function sendToCph(problem: CphProblem): Promise<void> {
                     if (res.statusCode && res.statusCode >= 200 && res.statusCode < 300) {
                         resolve();
                     } else {
-                        reject(new Error(`CPH 返回状态码 ${res.statusCode}`));
+                        reject(new Error(t("cph.httpError", { status: res.statusCode })));
                     }
                 });
             }
@@ -75,7 +73,7 @@ export function sendToCph(problem: CphProblem): Promise<void> {
             if ((err as NodeJS.ErrnoException).code === "ECONNREFUSED") {
                 reject(new CphNotRunningError());
             } else {
-                reject(new Error(`连接 CPH 失败: ${err.message}`));
+                reject(new Error(t("cph.connectionFailed", { msg: err.message })));
             }
         });
         req.write(body);
diff --git a/apps/vscode-extension/src/tools/deepl.ts b/apps/vscode-extension/src/tools/deepl.ts
index 5f80550..6762ffb 100644
--- a/apps/vscode-extension/src/tools/deepl.ts
+++ b/apps/vscode-extension/src/tools/deepl.ts
@@ -1,4 +1,5 @@
 import * as https from "https";
+import { t } from "./i18n";
 
 let freeDeeplID = 1;
 
@@ -56,7 +57,7 @@ export async function translateTextFree(text: string, lang: string): Promise<str
                 res.on("end", () => {
                     settle(() => {
                         if (res.statusCode && res.statusCode >= 400) {
-                            reject(new Error(res.statusCode === 429 ? "翻译请求过于频繁，请稍后再试" : `翻译接口错误 (${res.statusCode})`));
+                            reject(new Error(res.statusCode === 429 ? t("deepl.tooFrequent") : t("deepl.httpError", { status: res.statusCode })));
                             return;
                         }
                         try {
@@ -64,19 +65,19 @@ export async function translateTextFree(text: string, lang: string): Promise<str
                             if (json?.result?.texts?.[0]?.text) {
                                 resolve(json.result.texts[0].text);
                             } else {
-                                reject(new Error("翻译接口返回异常"));
+                                reject(new Error(t("deepl.badResponse")));
                             }
                         } catch {
-                            reject(new Error("翻译接口返回异常"));
+                            reject(new Error(t("deepl.badResponse")));
                         }
                     });
                 });
             }
         );
 
-        req.setTimeout(20000, () => req.destroy(new Error("翻译请求超时")));
+        req.setTimeout(20000, () => req.destroy(new Error(t("deepl.timeout"))));
         req.on("error", (err: Error) =>
-            settle(() => reject(new Error(err.message === "翻译请求超时" ? "翻译请求超时" : `翻译请求失败: ${err.message}`)))
+            settle(() => reject(new Error(err.message === t("deepl.timeout") ? t("deepl.timeout") : t("deepl.failed", { msg: err.message }))))
         );
         req.write(postData);
         req.end();
@@ -104,17 +105,17 @@ export function translateTextRaw(text: string, targetLang: string, apiKey: strin
                     try {
                         const json = JSON.parse(data);
                         if (res.statusCode && res.statusCode >= 400) {
-                            reject(new Error(json.message || `翻译接口错误 (${res.statusCode})`));
+                            reject(new Error(json.message || t("deepl.httpError", { status: res.statusCode })));
                             return;
                         }
                         resolve(json.translations?.[0]?.text ?? text);
                     } catch {
-                        reject(new Error("翻译接口返回异常"));
+                        reject(new Error(t("deepl.badResponse")));
                     }
                 });
             }
         );
-        req.on("error", () => reject(new Error("翻译请求失败")));
+        req.on("error", () => reject(new Error(t("deepl.failedSimple"))));
         req.write(params.toString());
         req.end();
     });
diff --git a/apps/vscode-extension/src/tools/fetch.ts b/apps/vscode-extension/src/tools/fetch.ts
index b3b914e..db9a9df 100644
--- a/apps/vscode-extension/src/tools/fetch.ts
+++ b/apps/vscode-extension/src/tools/fetch.ts
@@ -5,12 +5,13 @@ import * as zlib from "zlib";
 import * as net from "net";
 import * as tls from "tls";
 import { SubRecord } from "./types"
+import { t } from "./i18n"
 
 
 export class CfError extends Error {
 	url: string;
 	constructor(url: string) {
-		super(`AtCoder 触发了 Cloudflare 验证，插件无法绕过。请在浏览器中直接访问 AtCoder。\nURL: ${url}`);
+		super(t("err.cf", { url }));
 		this.name = "CfError";
 		this.url = url;
 	}
@@ -18,14 +19,7 @@ export class CfError extends Error {
 
 export class ProxyError extends Error {
 	constructor() {
-		super(
-			`网络代理连接失败，无法访问 AtCoder。\n` +
-			`可能原因：在 WSL 2 中，代理地址 127.0.0.1 指向 WSL 而非 Windows 宿主机。\n` +
-			`解决方案：\n` +
-			`  1. 在 WSL 中执行: export NO_PROXY=.atcoder.jp\n` +
-			`  2. 或设置正确的宿主机 IP: export HTTPS_PROXY=http://$(hostname).local:7897\n` +
-			`  3. 或连接 Windows 宿主机的 WSL 网关 IP（查看 /etc/resolv.conf）`
-		);
+		super(t("err.proxy"));
 		this.name = "ProxyError";
 	}
 }
@@ -33,14 +27,7 @@ export class ProxyError extends Error {
 export class LoginRequiredError extends Error {
 	url: string;
 	constructor(url: string) {
-		super(
-			`访问需要登录，请设置 AtCoder Cookie。\n` +
-			`获取方法：\n` +
-			`  1. 在浏览器中登录 https://atcoder.jp\n` +
-			`  2. 按 F12 打开开发者工具 → Application → Cookies\n` +
-			`  3. 找到 atcoder.jp 下的 REVEL_SESSION，复制其 Value\n` +
-			`  4. 在插件设置中输入: REVEL_SESSION=复制的值`
-		);
+		super(t("err.login"));
 		this.name = "LoginRequiredError";
 		this.url = url;
 	}
@@ -278,7 +265,7 @@ function handleResponse(
 				reject(new CfError(url));
 			} else {
 				console.log(`${logPrefix} 403 但非 CF，可能 Cookie 无效`);
-				reject(new Error(`访问被拒绝 (403)。Cookie 可能无效或已过期，请重新登录 AtCoder 获取新的 REVEL_SESSION`));
+				reject(new Error(t("err.http403")));
 			}
 			return;
 		}
@@ -291,12 +278,12 @@ function handleResponse(
 			if (res.statusCode === 404) {
 				if (!sessionCookie) {
 					console.log(`${logPrefix} 404 且无 Cookie，需要登录`);
-					reject(new Error(`访问失败 (404)。题目不存在或需要登录，请先设置 AtCoder Cookie。`));
+					reject(new Error(t("err.http404NoCookie")));
 					return;
 				}
 				const rejectCookieInvalid = () => {
 					console.log(`${logPrefix} 404 但有 Cookie，可能 Cookie 无效`);
-					reject(new Error(`访问失败 (404)。Cookie 可能无效或已过期，请重新登录 AtCoder 获取新的 REVEL_SESSION`));
+					reject(new Error(t("err.http404BadCookie")));
 				};
 				const contest = extractContestFromUrl(url);
 				if (!contest) {
@@ -306,7 +293,7 @@ function handleResponse(
 				void isContestStarted(contest).then((started) => {
 					if (started === false) {
 						console.log(`${logPrefix} 404 且比赛未开始，题目未公开: ${url}`);
-						reject(new Error(`访问失败 (404)。比赛「${contest}」尚未开始，题目还未公开，请等待开赛后再试。`));
+						reject(new Error(t("err.http404NotStarted", { contest })));
 					} else {
 						rejectCookieInvalid();
 					}
@@ -314,7 +301,7 @@ function handleResponse(
 				return;
 			}
 			console.log(`${logPrefix} 非 200 状态码:`, res.statusCode);
-			reject(new Error(`Request failed with status ${res.statusCode}`));
+			reject(new Error(t("err.httpStatus", { status: res.statusCode })));
 			return;
 		}
 
@@ -371,7 +358,7 @@ function fetchTextOnce(url: string, withCookie: boolean): Promise<string> {
 				reject(new ProxyError());
 				return;
 			}
-			reject(new Error(`网络错误: ${err.message}`));
+			reject(new Error(t("err.network", { msg: err.message })));
 		});
 	});
 }
@@ -413,7 +400,7 @@ export function fetchTextPost(url: string, body: string): Promise<string> {
 				reject(new ProxyError());
 				return;
 			}
-			reject(new Error(`网络错误: ${err.message}`));
+			reject(new Error(t("err.network", { msg: err.message })));
 		});
 	});
 }
diff --git a/apps/vscode-extension/src/tools/handle.ts b/apps/vscode-extension/src/tools/handle.ts
index 36d040f..756240b 100644
--- a/apps/vscode-extension/src/tools/handle.ts
+++ b/apps/vscode-extension/src/tools/handle.ts
@@ -9,19 +9,20 @@ import { fetchStandings } from "./standings";
 import { fetchHomepageContests } from "./homepage";
 import { fetchSubmissionDetail } from "./submission";
 import { pullSubmitStatu, notifyCookieChanged } from "../extension";
+import { t } from "./i18n";
 
 export function handleErrorWithCfAndLogin(error: unknown, send: (payload: Record<string, unknown>) => void): boolean {
     if (error instanceof CfError) {
-        vscode.window.showErrorMessage(error.message, "在浏览器中打开").then((choice) => {
-            if (choice === "在浏览器中打开") vscode.env.openExternal(vscode.Uri.parse(error.url));
+        vscode.window.showErrorMessage(error.message, t("err.openInBrowser")).then((choice) => {
+            if (choice === t("err.openInBrowser")) vscode.env.openExternal(vscode.Uri.parse(error.url));
         });
         send({ type: "cf_challenge", url: error.url });
         return true;
     }
     if (error instanceof ProxyError) {
-        const fixNoProxy = "设置 NO_PROXY";
-        const fixWsl = "查看 WSL 代理说明";
-        vscode.window.showErrorMessage("代理连接失败，无法访问 AtCoder", fixNoProxy, fixWsl).then((choice) => {
+        const fixNoProxy = t("err.setNoProxy");
+        const fixWsl = t("err.viewWslDoc");
+        vscode.window.showErrorMessage(t("err.proxyFailedTitle"), fixNoProxy, fixWsl).then((choice) => {
             if (choice === fixNoProxy) vscode.env.openExternal(vscode.Uri.parse("https://github.com/anomalyco/opencode/issues"));
             if (choice === fixWsl) vscode.env.openExternal(vscode.Uri.parse("https://learn.microsoft.com/zh-cn/windows/wsl/networking"));
         });
@@ -36,7 +37,7 @@ export function handleErrorWithCfAndLogin(error: unknown, send: (payload: Record
 }
 
 export async function handleContestLoad(contest: string, send: (payload: Record<string, unknown>) => void) {
-    send({ type: "loading", text: `正在抓取 ${contest} 的题目列表...` });
+    send({ type: "loading", text: t("load.contestTasks", { contest }) });
     try {
         const tasks = await fetchAtCoderTasks(contest);
         try {
@@ -48,7 +49,7 @@ export async function handleContestLoad(contest: string, send: (payload: Record<
         }
     } catch (error) {
         if (!handleErrorWithCfAndLogin(error, send)) {
-            send({ type: "error", text: error instanceof Error ? error.message : "抓取题目失败" });
+            send({ type: "error", text: error instanceof Error ? error.message : t("err.contestTasks") });
         }
         return;
     }
@@ -76,40 +77,40 @@ export async function handleTranslate(
         if (translationMode === "free") {
             for (const [key, value] of Object.entries(texts)) {
                 if (typeof value === "string" && value.trim()) {
-                    send({ type: "loading", text: `正在翻译 ${key}...` });
+                    send({ type: "loading", text: t("load.translateItem", { name: key }) });
                     translated[key] = await translateTextFree(value, lang);
                 }
             }
         } else {
             const apiKey = await context.secrets.get("deeplApiKey");
             if (!apiKey) {
-                const set = "设置 API Key";
-                const choice = await vscode.window.showErrorMessage("请先设置 DeepL API Key", set);
+                const set = t("deepl.setKey");
+                const choice = await vscode.window.showErrorMessage(t("deepl.setKeyFirst"), set);
                 if (choice === set) vscode.commands.executeCommand("extension.setDeeplApiKey");
-                send({ type: "error", text: "未设置 DeepL API Key" });
+                send({ type: "error", text: t("deepl.noKey") });
                 return;
             }
             for (const [key, value] of Object.entries(texts)) {
                 if (typeof value === "string" && value.trim()) {
-                    send({ type: "loading", text: `正在翻译 ${key}...` });
+                    send({ type: "loading", text: t("load.translateItem", { name: key }) });
                     translated[key] = await translateTextRaw(value, lang, apiKey);
                 }
             }
         }
         send({ type: "translation", translated });
     } catch (error) {
-        send({ type: "error", text: error instanceof Error ? error.message : "翻译失败" });
+        send({ type: "error", text: error instanceof Error ? error.message : t("err.translate") });
     }
 }
 
 export async function handleProblemLoad(contest: string, task: string, send: (payload: Record<string, unknown>) => void) {
-    send({ type: "loading", text: `正在抓取 ${contest}/${task} 的题面...` });
+    send({ type: "loading", text: t("load.problem", { contest, task }) });
     try {
         const problem = await fetchAtCoderProblem(contest, task);
         send({ type: "problem", problem });
     } catch (error) {
         if (!handleErrorWithCfAndLogin(error, send)) {
-            send({ type: "error", text: error instanceof Error ? error.message : "抓取题面失败" });
+            send({ type: "error", text: error instanceof Error ? error.message : t("err.problem") });
         }
     }
 }
@@ -121,7 +122,7 @@ export async function handleGetCookie(context: vscode.ExtensionContext, send: (p
         type: "cookieStatus",
         hasCookie: !!storedCookie,
         masked,
-        statusMessage: storedCookie ? "✅ Cookie 已加载，可访问需要登录的题目" : "未设置 Cookie",
+        statusMessage: storedCookie ? t("cookie.loaded") : t("cookie.notSet"),
     });
 }
 
@@ -132,59 +133,59 @@ export async function handleSetCookie(
 ) {
     if (cookie) {
         if (!cookie.startsWith("REVEL_SESSION=")) {
-            send({ type: "cookieStatus", hasCookie: false, statusMessage: "❌ Cookie 格式错误，请以 REVEL_SESSION= 开头" });
+            send({ type: "cookieStatus", hasCookie: false, statusMessage: t("cookie.formatError") });
             return;
         }
         if (cookie.length < 20) {
-            send({ type: "cookieStatus", hasCookie: false, statusMessage: "❌ Cookie 值过短，请确认已完整复制 REVEL_SESSION 的值" });
+            send({ type: "cookieStatus", hasCookie: false, statusMessage: t("cookie.tooShort") });
             return;
         }
         await context.secrets.store("atcoderCookie", cookie);
         setSessionCookie(cookie);
-        vscode.window.showInformationMessage("AtCoder Cookie 已保存");
-        send({ type: "cookieStatus", hasCookie: true, statusMessage: "✅ Cookie 保存成功" });
+        vscode.window.showInformationMessage(t("cookie.saved"));
+        send({ type: "cookieStatus", hasCookie: true, statusMessage: t("cookie.saveSuccess") });
         notifyCookieChanged(true);
     } else {
         await context.secrets.delete("atcoderCookie");
         setSessionCookie("");
-        send({ type: "cookieStatus", hasCookie: false, statusMessage: "Cookie 已清除" });
+        send({ type: "cookieStatus", hasCookie: false, statusMessage: t("cookie.cleared") });
     }
 }
 
 export async function handleRegistration(contest: string, rated: boolean | undefined, send: (payload: Record<string, unknown>) => void) {
-    send({ type: "loading", text: `正在报名 ${contest} ...` });
+    send({ type: "loading", text: t("load.register", { contest }) });
     try {
         const page = await fetchContest(contest);
         if (page.signed) {
-            send({ type: "registrationStatus", signed: true, registrationMessage: "已报名，无需重复操作" });
+            send({ type: "registrationStatus", signed: true, registrationMessage: t("register.already") });
             return;
         }
         const result = await signedUpContest(contest, page.csrfToken, rated);
         send({ type: "registrationStatus", signed: result.success, registrationMessage: result.message });
     } catch (error) {
         if (!handleErrorWithCfAndLogin(error, send)) {
-            send({ type: "registrationStatus", signed: false, registrationMessage: error instanceof Error ? error.message : "报名失败" });
+            send({ type: "registrationStatus", signed: false, registrationMessage: error instanceof Error ? error.message : t("register.failed") });
         }
     }
 }
 
 export async function handleFetchSubmitPage(contest: string, send: (payload: Record<string, unknown>) => void) {
-    send({ type: "loading", text: `正在获取 ${contest} 提交页面信息...` });
+    send({ type: "loading", text: t("load.submitPage", { contest }) });
     try {
         const pageData = await fetchSubmitPage(contest);
         send({ type: "submitPage", submitTasks: pageData.tasks, languages: pageData.languages, csrfToken: pageData.csrfToken });
-        send({ type: "update", text: "已获取提交页面信息" });
+        send({ type: "update", text: t("submit.pageReady") });
     } catch (error) {
         if (error instanceof CfError) {
-            send({ type: "submitPageError", message: "该比赛提交需要 Cloudflare 验证，插件无法自动完成。请在浏览器中打开提交页完成验证后提交。", url: error.url });
+            send({ type: "submitPageError", message: t("submit.cfNeedBrowser"), url: error.url });
             return;
         }
         if (error instanceof LoginRequiredError) {
             send({
                 type: "submitPageError",
                 message: getSessionCookie()
-                    ? "提交需要登录，请检查 AtCoder Cookie 是否有效或已过期；若提交页触发 Cloudflare 验证，请用浏览器打开完成验证。"
-                    : "提交需要登录，请先设置 AtCoder Cookie 后再试。",
+                    ? t("submit.loginRequired")
+                    : t("submit.loginRequiredNoCookie"),
                 url: `https://atcoder.jp/contests/${contest}/submit`,
             });
             return;
@@ -192,7 +193,7 @@ export async function handleFetchSubmitPage(contest: string, send: (payload: Rec
         if (!handleErrorWithCfAndLogin(error, send)) {
             send({
                 type: "submitPageError",
-                message: error instanceof Error ? error.message : "获取提交页面失败",
+                message: error instanceof Error ? error.message : t("err.submitPage"),
                 url: `https://atcoder.jp/contests/${contest}/submit`,
             });
         }
@@ -207,15 +208,15 @@ export async function handleSubmitCode(
     send: (payload: Record<string, unknown>) => void,
 ) {
     if (!taskScreenName || !languageId || !sourceCode) {
-        send({ type: "submitResult", submitResult: { success: false, message: "提交参数不完整" } });
+        send({ type: "submitResult", submitResult: { success: false, message: t("submit.paramsIncomplete") } });
         return;
     }
-    send({ type: "loading", text: "正在提交代码..." });
+    send({ type: "loading", text: t("load.submitting") });
     try {
         const result = await submitCodeWithRedirect(contest, taskScreenName, languageId, sourceCode);
         send({ type: "submitResult", submitResult: result });
         if (result.success) {
-            send({ type: "update", text: "代码提交成功，正在获取评测结果..." });
+            send({ type: "update", text: t("submit.successWaiting") });
             try {
                 await pullSubmitStatu(contest, taskScreenName!, send);
             } catch {
@@ -229,7 +230,7 @@ export async function handleSubmitCode(
         } else send({ type: "error", text: result.message });
     } catch (error) {
         if (error instanceof CfError) {
-            send({ type: "submitResult", submitResult: { success: false, message: "该比赛提交需要 Cloudflare 验证，插件无法自动完成。请在浏览器中打开提交页完成验证后提交。" } });
+            send({ type: "submitResult", submitResult: { success: false, message: t("submit.cfNeedBrowser") } });
             return;
         }
         if (error instanceof LoginRequiredError) {
@@ -238,62 +239,62 @@ export async function handleSubmitCode(
                 submitResult: {
                     success: false,
                     message: getSessionCookie()
-                        ? "提交需要登录，请检查 AtCoder Cookie 是否有效或已过期；若提交页触发 Cloudflare 验证，请用浏览器打开完成验证。"
-                        : "提交需要登录，请先设置 AtCoder Cookie 后再试。",
+                        ? t("submit.loginRequired")
+                        : t("submit.loginRequiredNoCookie"),
                 },
             });
             return;
         }
         if (!handleErrorWithCfAndLogin(error, send)) {
-            send({ type: "submitResult", submitResult: { success: false, message: error instanceof Error ? error.message : "提交失败" } });
+            send({ type: "submitResult", submitResult: { success: false, message: error instanceof Error ? error.message : t("err.submit") } });
         }
     }
 }
 
 export async function handleFetchSubHistory(contest: string, send: (payload: Record<string, unknown>) => void) {
-    send({ type: "loading", text: `正在获取 ${contest} 提交记录...` });
+    send({ type: "loading", text: t("load.subHistory", { contest }) });
     try {
         const submissions = await fetchSubmitHistory(contest);
         send({ type: "submissionHistory", submissions });
     } catch (error) {
         if (!handleErrorWithCfAndLogin(error, send)) {
-            send({ type: "error", text: error instanceof Error ? error.message : "获取提交记录失败" });
+            send({ type: "error", text: error instanceof Error ? error.message : t("err.subHistory") });
         }
     }
 }
 
 export async function handleFetchSubmissionDetail(contest: string, id: string, send: (payload: Record<string, unknown>) => void) {
-    send({ type: "loading", text: `正在获取提交 ${id} 的详细信息...` });
+    send({ type: "loading", text: t("load.subDetail", { id }) });
     try {
         const detail = await fetchSubmissionDetail(contest, id);
         send({ type: "submissionDetail", submissionDetail: detail });
     } catch (error) {
         if (!handleErrorWithCfAndLogin(error, send)) {
-            send({ type: "error", text: error instanceof Error ? error.message : "获取提交详情失败" });
+            send({ type: "error", text: error instanceof Error ? error.message : t("err.subDetail") });
         }
     }
 }
 
 export async function handleFetchStandings(contest: string, send: (payload: Record<string, unknown>) => void) {
-    send({ type: "loading", text: `正在获取 ${contest} 排行榜...` });
+    send({ type: "loading", text: t("load.standings", { contest }) });
     try {
         const standings = await fetchStandings(contest);
         send({ type: "standings", contest, standings });
     } catch (error) {
         if (!handleErrorWithCfAndLogin(error, send)) {
-            send({ type: "error", text: error instanceof Error ? error.message : "获取排行榜失败" });
+            send({ type: "error", text: error instanceof Error ? error.message : t("err.standings") });
         }
     }
 }
 
 export async function handleGetContests(send: (payload: Record<string, unknown>) => void) {
-    send({ type: "loading", text: "正在抓取 AtCoder 首页比赛列表..." });
+    send({ type: "loading", text: t("load.homepage") });
     try {
         const contests = await fetchHomepageContests();
         send({ type: "contestList", contests });
     } catch (error) {
         if (!handleErrorWithCfAndLogin(error, send)) {
-            send({ type: "error", text: error instanceof Error ? error.message : "获取比赛列表失败" });
+            send({ type: "error", text: error instanceof Error ? error.message : t("err.homepage") });
         }
     }
 }
@@ -302,9 +303,9 @@ export async function handleExportToCph(problem: AtCoderProblem, send: (payload:
     try {
         const payload = buildCphProblem(problem);
         await sendToCph(payload);
-        send({ type: "cphExportResult", success: true, message: "success send to cph" });
+        send({ type: "cphExportResult", success: true, message: t("cph.exportSuccess") });
     } catch (error) {
-        const message = error instanceof Error ? error.message : "fail to send cph";
+        const message = error instanceof Error ? error.message : t("cph.exportFailed");
         send({ type: "cphExportResult", success: false, message: message });
     }
 }
\ No newline at end of file
diff --git a/apps/vscode-extension/src/tools/i18n/en.ts b/apps/vscode-extension/src/tools/i18n/en.ts
new file mode 100644
index 0000000..43c203b
--- /dev/null
+++ b/apps/vscode-extension/src/tools/i18n/en.ts
@@ -0,0 +1,120 @@
+import type { ZhDict } from "./zh";
+
+export const en: Record<keyof ZhDict, string> = {
+    "ext.judgeResult": "Judge result: {status}",
+    "ext.judgeTimeout": "Judging timed out, please refresh later to check the result",
+    "ext.promptDeeplKey": "Enter DeepL API Key",
+    "ext.placeholderDeeplKey": "e.g. xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx:fx",
+    "ext.deeplKeySaved": "DeepL API Key saved",
+    "ext.promptCookie": "Paste your AtCoder Cookie (REVEL_SESSION only)",
+    "ext.placeholderCookie": "REVEL_SESSION=abcdef1234567890abcdef1234567890",
+    "ext.cookieFormatWarn": "The Cookie format looks incorrect. Add the REVEL_SESSION= prefix?",
+    "ext.autoFix": "Auto fix",
+    "ext.cancel": "Cancel",
+    "ext.cookieSavedFixed": "AtCoder Cookie saved with auto-fixed format",
+    "ext.cookieSaved": "AtCoder Cookie saved",
+    "ext.submissionPanelTitle": "Submission {id} - {contest}",
+
+    "cmd.copied": "Copied to clipboard",
+    "cmd.unknown": "Unknown command",
+
+    "err.openInBrowser": "Open in Browser",
+    "err.proxyFailedTitle": "Proxy connection failed, cannot reach AtCoder",
+    "err.setNoProxy": "Set NO_PROXY",
+    "err.viewWslDoc": "View WSL proxy docs",
+    "load.contestTasks": "Fetching task list for {contest}...",
+    "err.contestTasks": "Failed to fetch task list",
+    "err.standingsParse": "Failed to parse standings data: {reason}",
+    "load.translateItem": "Translating {name}...",
+    "deepl.setKeyFirst": "Please set a DeepL API Key first",
+    "deepl.setKey": "Set API Key",
+    "deepl.noKey": "DeepL API Key is not set",
+    "err.translate": "Translation failed",
+    "load.problem": "Fetching statement for {contest}/{task}...",
+    "err.problem": "Failed to fetch statement",
+    "cookie.loaded": "✅ Cookie loaded, can access login-required problems",
+    "cookie.notSet": "Cookie not set",
+    "cookie.formatError": "❌ Invalid Cookie format, it must start with REVEL_SESSION=",
+    "cookie.tooShort": "❌ Cookie value is too short, please make sure you copied the full REVEL_SESSION value",
+    "cookie.saved": "AtCoder Cookie saved",
+    "cookie.saveSuccess": "✅ Cookie saved",
+    "cookie.cleared": "Cookie cleared",
+    "load.register": "Registering for {contest} ...",
+    "register.already": "Already registered, no need to register again",
+    "register.failed": "Registration failed",
+    "load.submitPage": "Fetching submit page for {contest}...",
+    "submit.pageReady": "Submit page loaded",
+    "submit.cfNeedBrowser": "Submitting to this contest requires Cloudflare verification, which cannot be automated. Please open the submit page in your browser to complete verification before submitting.",
+    "submit.loginRequired": "Submission requires login. Please check whether your AtCoder Cookie is valid or expired; if the submit page triggers Cloudflare verification, open it in your browser to complete it.",
+    "submit.loginRequiredNoCookie": "Submission requires login. Please set your AtCoder Cookie first.",
+    "err.submitPage": "Failed to fetch submit page",
+    "submit.paramsIncomplete": "Incomplete submission parameters",
+    "load.submitting": "Submitting code...",
+    "submit.successWaiting": "Code submitted, fetching judge result...",
+    "err.submit": "Submission failed",
+    "load.subHistory": "Fetching submission history for {contest}...",
+    "err.subHistory": "Failed to fetch submission history",
+    "load.subDetail": "Fetching details for submission {id}...",
+    "err.subDetail": "Failed to fetch submission details",
+    "load.standings": "Fetching standings for {contest}...",
+    "err.standings": "Failed to fetch standings",
+    "load.homepage": "Fetching AtCoder homepage contest list...",
+    "err.homepage": "Failed to fetch contest list",
+    "cph.exportSuccess": "success send to cph",
+    "cph.exportFailed": "fail to send cph",
+
+    "err.cf": "AtCoder triggered a Cloudflare verification that cannot be bypassed. Please open AtCoder in your browser.\nURL: {url}",
+    "err.proxy":
+        "Network proxy connection failed, cannot reach AtCoder.\n" +
+        "Possible cause: In WSL 2, the proxy address 127.0.0.1 points to WSL itself, not the Windows host.\n" +
+        "Solutions:\n" +
+        "  1. Run in WSL: export NO_PROXY=.atcoder.jp\n" +
+        "  2. Or set the correct host IP: export HTTPS_PROXY=http://$(hostname).local:7897\n" +
+        "  3. Or connect to the Windows host via the WSL gateway IP (see /etc/resolv.conf)",
+    "err.login":
+        "Login is required, please set your AtCoder Cookie.\n" +
+        "How to get it:\n" +
+        "  1. Sign in at https://atcoder.jp in your browser\n" +
+        "  2. Press F12 to open DevTools → Application → Cookies\n" +
+        "  3. Find REVEL_SESSION under atcoder.jp and copy its Value\n" +
+        "  4. Enter it in the extension settings as: REVEL_SESSION=<value>",
+    "err.http403": "Access denied (403). The Cookie may be invalid or expired. Please sign in to AtCoder again and get a fresh REVEL_SESSION",
+    "err.http404NoCookie": "Request failed (404). The problem may not exist or requires login. Please set your AtCoder Cookie first.",
+    "err.http404BadCookie": "Request failed (404). The Cookie may be invalid or expired. Please sign in to AtCoder again and get a fresh REVEL_SESSION",
+    "err.http404NotStarted": "Request failed (404). The contest \"{contest}\" has not started yet; the problems are not public. Please wait until it begins.",
+    "err.httpStatus": "Request failed with status {status}",
+    "err.network": "Network error: {msg}",
+
+    "deepl.tooFrequent": "Too many translation requests, please try again later",
+    "deepl.httpError": "Translation API error ({status})",
+    "deepl.badResponse": "Translation API returned an unexpected response",
+    "deepl.timeout": "Translation request timed out",
+    "deepl.failed": "Translation request failed: {msg}",
+    "deepl.failedSimple": "Translation request failed",
+
+    "submit.pageFetchFailed": "Cannot fetch the submit page: the contest may have ended, or the submit page structure has changed.",
+    "submit.noCsrf": "Cannot get CSRF Token, please check whether the Cookie is valid",
+    "submit.success": "Code submitted successfully",
+    "submit.failed": "Submission failed, please check whether the Cookie is valid",
+
+    "register.success": "Registered successfully!",
+    "register.failedBadCookie": "Registration failed, please check whether the Cookie is valid",
+    "register.formIncomplete": "Registration was not successful: the register page returned a validation result. Please make sure all required fields (e.g. name, email, location) are filled in.",
+    "register.alreadyDone": "Already registered",
+    "register.closed": "Registration is closed or the registration info could not be fetched",
+    "register.requestFailed": "Registration request failed",
+
+    "md.statement": "### Problem Statement",
+    "md.constraints": "### Constraints",
+    "md.inputFormat": "### Input Format",
+    "md.outputFormat": "### Output Format",
+    "md.sample": "### Sample {index}",
+    "md.inputLabel": "Input",
+    "md.outputLabel": "Output",
+
+    "cph.notRunning":
+        "CPH extension not detected (no response on localhost:27121).\n" +
+        "Please install and enable the Competitive Programming Helper extension and try again.",
+    "cph.httpError": "CPH returned status code {status}",
+    "cph.connectionFailed": "Failed to connect to CPH: {msg}",
+};
diff --git a/apps/vscode-extension/src/tools/i18n/index.ts b/apps/vscode-extension/src/tools/i18n/index.ts
new file mode 100644
index 0000000..1341c03
--- /dev/null
+++ b/apps/vscode-extension/src/tools/i18n/index.ts
@@ -0,0 +1,28 @@
+import { zh } from "./zh";
+import { en } from "./en";
+import type { ZhDict } from "./zh";
+
+type Dict = Record<string, string>;
+
+const dicts: Record<string, Dict> = { zh, en };
+const fallback: Dict = en;
+
+let currentLang = "en";
+
+export function init(language: string): void {
+    const lang = (language || "en").toLowerCase();
+    currentLang = lang.startsWith("zh") ? "zh" : "en";
+}
+
+export type I18nKey = keyof ZhDict;
+
+export function t(key: I18nKey, params?: Record<string, string | number | undefined>): string {
+    const dict = dicts[currentLang] ?? fallback;
+    let text = dict[key] ?? fallback[key] ?? key;
+    if (params) {
+        for (const [k, v] of Object.entries(params)) {
+            text = text.replace(new RegExp(`\\{${k}\\}`, "g"), String(v));
+        }
+    }
+    return text;
+}
diff --git a/apps/vscode-extension/src/tools/i18n/zh.ts b/apps/vscode-extension/src/tools/i18n/zh.ts
new file mode 100644
index 0000000..b73fcfe
--- /dev/null
+++ b/apps/vscode-extension/src/tools/i18n/zh.ts
@@ -0,0 +1,120 @@
+export const zh = {
+    "ext.judgeResult": "评测结果: {status}",
+    "ext.judgeTimeout": "评测超时，请稍后手动刷新查看结果",
+    "ext.promptDeeplKey": "请输入 DeepL API Key",
+    "ext.placeholderDeeplKey": "例如 xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx:fx",
+    "ext.deeplKeySaved": "DeepL API Key 已保存",
+    "ext.promptCookie": "粘贴 AtCoder 的 Cookie（仅需 REVEL_SESSION）",
+    "ext.placeholderCookie": "REVEL_SESSION=abcdef1234567890abcdef1234567890",
+    "ext.cookieFormatWarn": "Cookie 格式似乎不正确，是否添加 REVEL_SESSION= 前缀？",
+    "ext.autoFix": "自动修复",
+    "ext.cancel": "取消",
+    "ext.cookieSavedFixed": "AtCoder Cookie 已保存并自动修复格式",
+    "ext.cookieSaved": "AtCoder Cookie 已保存",
+    "ext.submissionPanelTitle": "提交 {id} - {contest}",
+
+    "cmd.copied": "已复制到剪贴板",
+    "cmd.unknown": "未知命令",
+
+    "err.openInBrowser": "在浏览器中打开",
+    "err.proxyFailedTitle": "代理连接失败，无法访问 AtCoder",
+    "err.setNoProxy": "设置 NO_PROXY",
+    "err.viewWslDoc": "查看 WSL 代理说明",
+    "load.contestTasks": "正在抓取 {contest} 的题目列表...",
+    "err.contestTasks": "抓取题目失败",
+    "err.standingsParse": "排行榜数据解析失败: {reason}",
+    "load.translateItem": "正在翻译 {name}...",
+    "deepl.setKeyFirst": "请先设置 DeepL API Key",
+    "deepl.setKey": "设置 API Key",
+    "deepl.noKey": "未设置 DeepL API Key",
+    "err.translate": "翻译失败",
+    "load.problem": "正在抓取 {contest}/{task} 的题面...",
+    "err.problem": "抓取题面失败",
+    "cookie.loaded": "✅ Cookie 已加载，可访问需要登录的题目",
+    "cookie.notSet": "未设置 Cookie",
+    "cookie.formatError": "❌ Cookie 格式错误，请以 REVEL_SESSION= 开头",
+    "cookie.tooShort": "❌ Cookie 值过短，请确认已完整复制 REVEL_SESSION 的值",
+    "cookie.saved": "AtCoder Cookie 已保存",
+    "cookie.saveSuccess": "✅ Cookie 保存成功",
+    "cookie.cleared": "Cookie 已清除",
+    "load.register": "正在报名 {contest} ...",
+    "register.already": "已报名，无需重复操作",
+    "register.failed": "报名失败",
+    "load.submitPage": "正在获取 {contest} 提交页面信息...",
+    "submit.pageReady": "已获取提交页面信息",
+    "submit.cfNeedBrowser": "该比赛提交需要 Cloudflare 验证，插件无法自动完成。请在浏览器中打开提交页完成验证后提交。",
+    "submit.loginRequired": "提交需要登录，请检查 AtCoder Cookie 是否有效或已过期；若提交页触发 Cloudflare 验证，请用浏览器打开完成验证。",
+    "submit.loginRequiredNoCookie": "提交需要登录，请先设置 AtCoder Cookie 后再试。",
+    "err.submitPage": "获取提交页面失败",
+    "submit.paramsIncomplete": "提交参数不完整",
+    "load.submitting": "正在提交代码...",
+    "submit.successWaiting": "代码提交成功，正在获取评测结果...",
+    "err.submit": "提交失败",
+    "load.subHistory": "正在获取 {contest} 提交记录...",
+    "err.subHistory": "获取提交记录失败",
+    "load.subDetail": "正在获取提交 {id} 的详细信息...",
+    "err.subDetail": "获取提交详情失败",
+    "load.standings": "正在获取 {contest} 排行榜...",
+    "err.standings": "获取排行榜失败",
+    "load.homepage": "正在抓取 AtCoder 首页比赛列表...",
+    "err.homepage": "获取比赛列表失败",
+    "cph.exportSuccess": "success send to cph",
+    "cph.exportFailed": "fail to send cph",
+
+    "err.cf": "AtCoder 触发了 Cloudflare 验证，插件无法绕过。请在浏览器中直接访问 AtCoder。\nURL: {url}",
+    "err.proxy":
+        "网络代理连接失败，无法访问 AtCoder。\n" +
+        "可能原因：在 WSL 2 中，代理地址 127.0.0.1 指向 WSL 而非 Windows 宿主机。\n" +
+        "解决方案：\n" +
+        "  1. 在 WSL 中执行: export NO_PROXY=.atcoder.jp\n" +
+        "  2. 或设置正确的宿主机 IP: export HTTPS_PROXY=http://$(hostname).local:7897\n" +
+        "  3. 或连接 Windows 宿主机的 WSL 网关 IP（查看 /etc/resolv.conf）",
+    "err.login":
+        "访问需要登录，请设置 AtCoder Cookie。\n" +
+        "获取方法：\n" +
+        "  1. 在浏览器中登录 https://atcoder.jp\n" +
+        "  2. 按 F12 打开开发者工具 → Application → Cookies\n" +
+        "  3. 找到 atcoder.jp 下的 REVEL_SESSION，复制其 Value\n" +
+        "  4. 在插件设置中输入: REVEL_SESSION=复制的值",
+    "err.http403": "访问被拒绝 (403)。Cookie 可能无效或已过期，请重新登录 AtCoder 获取新的 REVEL_SESSION",
+    "err.http404NoCookie": "访问失败 (404)。题目不存在或需要登录，请先设置 AtCoder Cookie。",
+    "err.http404BadCookie": "访问失败 (404)。Cookie 可能无效或已过期，请重新登录 AtCoder 获取新的 REVEL_SESSION",
+    "err.http404NotStarted": "访问失败 (404)。比赛「{contest}」尚未开始，题目还未公开，请等待开赛后再试。",
+    "err.httpStatus": "Request failed with status {status}",
+    "err.network": "网络错误: {msg}",
+
+    "deepl.tooFrequent": "翻译请求过于频繁，请稍后再试",
+    "deepl.httpError": "翻译接口错误 ({status})",
+    "deepl.badResponse": "翻译接口返回异常",
+    "deepl.timeout": "翻译请求超时",
+    "deepl.failed": "翻译请求失败: {msg}",
+    "deepl.failedSimple": "翻译请求失败",
+
+    "submit.pageFetchFailed": "无法获取提交页面：比赛可能已结束，或提交页面结构发生了变化。",
+    "submit.noCsrf": "无法获取 CSRF Token，请检查 Cookie 是否有效",
+    "submit.success": "代码提交成功",
+    "submit.failed": "提交失败，请检查 Cookie 是否有效",
+
+    "register.success": "报名成功！",
+    "register.failedBadCookie": "报名失败，请检查 Cookie 是否有效",
+    "register.formIncomplete": "报名未成功：注册页返回校验结果，请确认表单必填信息（如姓名、邮箱、居住地等）填写完整",
+    "register.alreadyDone": "已报名",
+    "register.closed": "报名已截止或无法获取报名信息",
+    "register.requestFailed": "报名请求失败",
+
+    "md.statement": "### 题目描述",
+    "md.constraints": "### 约束",
+    "md.inputFormat": "### 输入格式",
+    "md.outputFormat": "### 输出格式",
+    "md.sample": "### 样例 {index}",
+    "md.inputLabel": "输入",
+    "md.outputLabel": "输出",
+
+    "cph.notRunning":
+        "未检测到 CPH 插件（localhost:27121 无响应）。\n" +
+        "请安装并启用 Competitive Programming Helper 扩展后重试。",
+    "cph.httpError": "CPH 返回状态码 {status}",
+    "cph.connectionFailed": "连接 CPH 失败: {msg}",
+};
+
+export type ZhDict = typeof zh;
diff --git a/apps/vscode-extension/src/tools/standings.ts b/apps/vscode-extension/src/tools/standings.ts
index fe22297..e0fe1ae 100644
--- a/apps/vscode-extension/src/tools/standings.ts
+++ b/apps/vscode-extension/src/tools/standings.ts
@@ -1,4 +1,5 @@
 import { fetchText } from "./fetch";
+import { t } from "./i18n";
 
 export interface Standing {
     rank: number;
@@ -22,7 +23,7 @@ export async function fetchStandings(contest: string, limit = 100): Promise<Stan
         data = JSON.parse(text) as Standings;
     } catch (error) {
         const reason = error instanceof Error ? error.message : "invalid json";
-        throw new Error(`排行榜数据解析失败: ${reason}`);
+        throw new Error(t("err.standingsParse", { reason }));
     }
     const rows = data.StandingsData ?? [];
     return rows.slice(0, limit).map((item) => ({
diff --git a/apps/vscode-extension/src/tools/submit.ts b/apps/vscode-extension/src/tools/submit.ts
index a9b5e50..2f04e0a 100644
--- a/apps/vscode-extension/src/tools/submit.ts
+++ b/apps/vscode-extension/src/tools/submit.ts
@@ -1,4 +1,5 @@
 import { fetchText, fetchTextPost, CfError } from "./fetch";
+import { t } from "./i18n";
 
 export interface LanguageOption {
     id: string;
@@ -85,7 +86,7 @@ export async function fetchSubmitPage(contest: string): Promise<SubmitPage> {
     }
 
     if (!csrfToken || (tasks.length === 0 && langOptions.length === 0)) {
-        throw new Error("无法获取提交页面：比赛可能已结束，或提交页面结构发生了变化。");
+        throw new Error(t("submit.pageFetchFailed"));
     }
 
     const seen = new Set<string>();
@@ -129,18 +130,18 @@ export async function submitCode(contest: string, taskScreenName: string, langua
     if (responseHtml.includes("/submissions/me") || responseHtml.includes("Submission")) {
         return {
             success: true,
-            message: "代码提交成功",
+            message: t("submit.success"),
             url: `https://atcoder.jp/contests/${contest}/submissions/me`,
         };
     }
 
-    return { success: false, message: "提交失败，请检查 Cookie 是否有效" };
+    return { success: false, message: t("submit.failed") };
 }
 
 export async function submitCodeWithRedirect(contest: string, taskScreenName: string, languageId: string, sourceCode: string): Promise<SubmitStatus> {
     const pageData = await fetchSubmitPage(contest);
     if (!pageData.csrfToken) {
-        return { success: false, message: "无法获取 CSRF Token，请检查 Cookie 是否有效" };
+        return { success: false, message: t("submit.noCsrf") };
     }
     return await submitCode(contest, taskScreenName, languageId, sourceCode, pageData.csrfToken);
 }
diff --git a/apps/vscode-extension/src/tools/webview.ts b/apps/vscode-extension/src/tools/webview.ts
index 904f3a8..6aa9652 100644
--- a/apps/vscode-extension/src/tools/webview.ts
+++ b/apps/vscode-extension/src/tools/webview.ts
@@ -18,6 +18,7 @@ export function getWebviewContent(
     if (initSubmissionId) {
         globals.push(`window.__ATCODER_SUBMISSION_ID__ = ${JSON.stringify(initSubmissionId)};`);
     }
+    globals.push(`window.__ATCODER_LOCALE__ = ${JSON.stringify(vscode.env.language)};`);
     const initScript = globals.length > 0 ? `<script>${globals.join("")}</script>` : "";
     return `<!DOCTYPE html>
   <html lang="en">
diff --git a/packages/webview/src/ContestApp.tsx b/packages/webview/src/ContestApp.tsx
index 1005ec4..294891b 100644
--- a/packages/webview/src/ContestApp.tsx
+++ b/packages/webview/src/ContestApp.tsx
@@ -1,6 +1,7 @@
 import React from "react";
 import { Button, Card, Spinner } from "@template/ui";
 import { useVSCode } from "./VSCodeProvider";
+import { useI18n } from "./i18n";
 import type { ContestProblem, SampleCase, Standing, SubmissionRecord, WebviewMessage } from "./types";
 import { HtmlContent, TranslatedBlock } from "./components/HtmlContent";
 
@@ -28,10 +29,10 @@ interface TaskItem {
 }
 
 const TABS: Array<{ key: Tab; label: string }> = [
-    { key: "info", label: "信息" },
-    { key: "task", label: "题目" },
-    { key: "submit", label: "提交" },
-    { key: "rating", label: "排行" },
+    { key: "info", label: "ui.tabInfo" },
+    { key: "task", label: "ui.task" },
+    { key: "submit", label: "ui.submit" },
+    { key: "rating", label: "ui.tabRating" },
 ];
 
 const statusColor = (status: string): string => {
@@ -60,6 +61,7 @@ const formatSubmitTime = (time: string): string => {
 
 const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
     const vscode = useVSCode();
+    const { t } = useI18n();
     const contest = initContest;
     const [activeTab, setActiveTab] = React.useState<Tab>("task");
 
@@ -102,38 +104,38 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
 
     const loadProblem = (task: string) => {
         setIsLoading(true);
-        setStatus(`正在抓取 ${contest}/${task} 的题面...`);
+        setStatus(t("status.fetchingProblem", { contest, task }));
         setTranslated(translatedCache[task] ?? null);
         vscode.postMessage({ command: "loadProblem", contest, task });
     };
 
     const handleRegister = () => {
         setRegistrationMessage(null);
-        setStatus(`正在报名 ${contest} ...`);
+        setStatus(t("status.registration", { contest }));
         vscode.postMessage({ command: "registerContest", contest, rated: isRated });
     };
 
     const doTranslate = () => {
         if (!problem) return;
         setTranslating(true);
-        setStatus("正在翻译...");
+        setStatus(t("status.translating"));
         const texts: Record<string, string> = {};
-        if (problem.statement) texts["题目描述"] = problem.statement;
-        if (problem.constraints) texts["约束"] = problem.constraints;
-        if (problem.inputFormat) texts["输入格式"] = problem.inputFormat;
-        if (problem.outputFormat) texts["输出格式"] = problem.outputFormat;
+        if (problem.statement) texts[t("text.problemStatement")] = problem.statement;
+        if (problem.constraints) texts[t("text.constraints")] = problem.constraints;
+        if (problem.inputFormat) texts[t("text.inputFormat")] = problem.inputFormat;
+        if (problem.outputFormat) texts[t("text.outputFormat")] = problem.outputFormat;
         vscode.postMessage({ command: "translate", payload: texts, targetLang: "ZH", translationMode });
     };
 
     const doCopyMarkdown = () => {
         if (!problem) return;
         vscode.postMessage({ command: "copyMarkdown", problem });
-        setStatus("正在复制...");
+        setStatus(t("status.copying"));
     };
 
     const doExportToCph = () => {
         if (!problem) return;
-        setStatus("正在导出到 CPH...");
+        setStatus(t("status.exportingCph"));
         vscode.postMessage({ command: "sendCph", problem });
     };
 
@@ -143,14 +145,14 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
         setSubmitTasks([]);
         setSubmitLanguages([]);
         setSourceCode("");
-        setStatus("正在获取提交页面...");
+        setStatus(t("status.fetchingSubmitPage"));
         vscode.postMessage({ command: "fetchSubmitPage", contest });
     };
 
     const handleSubmitCode = () => {
         if (!selectedSubmitTask || !selectedSubmitLanguage || !sourceCode.trim()) return;
         setSubmitResult(null);
-        setStatus("正在提交代码...");
+        setStatus(t("status.submitting"));
         vscode.postMessage({
             command: "submitCode",
             contest,
@@ -162,7 +164,7 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
 
     const handleFetchHistory = () => {
         setLoadingHistory(true);
-        setStatus(`正在获取 ${contest} 提交记录...`);
+        setStatus(t("status.fetchingHistory", { contest }));
         vscode.postMessage({ command: "fetchSubmissionHistory", contest });
     };
 
@@ -170,7 +172,7 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
         setActiveTab(tab);
         if (tab === "rating" && !standingsCache.current[contest]) {
             setLoadingStandings(true);
-            setStatus(`正在获取 ${contest} 排行榜...`);
+            setStatus(t("status.fetchingStandings", { contest }));
             vscode.postMessage({ command: "fetchStandings", contest });
         }
     };
@@ -181,7 +183,7 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
 
     React.useEffect(() => {
         setIsLoading(true);
-        setStatus(`正在加载 ${contest} 的题目...`);
+        setStatus(t("status.loadingContest", { contest }));
         vscode.postMessage({ command: "loadContest", contest });
         vscode.postMessage({ command: "getCookie" });
     }, []);
@@ -193,7 +195,7 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
                 setTasks(message.tasks ?? []);
                 setSelectedTask("");
                 setProblem(null);
-                setStatus(`已加载 ${(message.tasks ?? []).length} 道题目`);
+                setStatus(t("status.tasksLoaded", { count: (message.tasks ?? []).length }));
                 setIsLoading(false);
             }
             if (message.type === "contestInfo") {
@@ -204,22 +206,22 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
             if (message.type === "cf_challenge") {
                 setCfUrl(message.url ?? null);
                 setIsLoading(false);
-                setStatus("AtCoder 触发 Cloudflare 验证，插件无法直接访问，请在浏览器中完成验证");
+                setStatus(t("status.cfChallenge"));
             }
             if (message.type === "loginRequired") {
                 setIsLoading(false);
-                setStatus("需要登录 AtCoder 账号，请在侧边栏设置 Cookie 后再试");
+                setStatus(t("status.loginRequiredSidebar"));
             }
             if (message.type === "problem") {
                 setProblem(message.problem ?? null);
-                setStatus(`已加载题面：${message.problem?.title ?? ""}`);
+                setStatus(t("status.problemLoaded", { title: message.problem?.title ?? "" }));
                 setIsLoading(false);
             }
             if (message.type === "loading" || message.type === "update") {
-                setStatus(message.text ?? "加载中...");
+                setStatus(message.text ?? t("status.loading"));
             }
             if (message.type === "error") {
-                setStatus(message.text ?? "操作失败");
+                setStatus(message.text ?? t("err.operationFailed"));
                 setIsLoading(false);
                 setTranslating(false);
                 setLoadingStandings(false);
@@ -232,7 +234,7 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
             if (message.type === "registrationStatus") {
                 setSigned(message.signed ?? false);
                 setRegistrationMessage(message.registrationMessage ?? null);
-                setStatus(message.registrationMessage ?? (message.signed ? "报名成功" : "报名失败"));
+                setStatus(message.registrationMessage ?? (message.signed ? t("status.registrationSuccess") : t("status.registrationFail")));
                 setIsLoading(false);
             }
             if (message.type === "translation") {
@@ -240,7 +242,7 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
                 setTranslatedCache((prev) => ({ ...prev, [key]: message.translated ?? {} }));
                 setTranslated(message.translated ?? null);
                 setTranslating(false);
-                setStatus("翻译完成");
+                setStatus(t("status.translationDone"));
             }
             if (message.type === "submitPage") {
                 setSubmitPageError(null);
@@ -252,34 +254,34 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
                 if (message.languages && message.languages.length > 0) {
                     setSelectedSubmitLanguage(message.languages[0].id);
                 }
-                setStatus("已获取提交页面信息");
+                setStatus(t("status.submitPageReady"));
                 setIsLoading(false);
             }
             if (message.type === "submitPageError") {
-                setSubmitPageError({ message: message.message ?? "提交页面无法访问", url: message.url });
-                setStatus(message.message ?? "提交页面无法访问");
+                setSubmitPageError({ message: message.message ?? t("err.submitPageUnavailable"), url: message.url });
+                setStatus(message.message ?? t("err.submitPageUnavailable"));
                 setIsLoading(false);
             }
             if (message.type === "submitResult") {
                 setSubmitResult(message.submitResult ?? null);
                 setIsLoading(false);
-                setStatus(message.submitResult?.success ? "代码提交成功" : (message.submitResult?.message ?? "提交失败"));
+                setStatus(message.submitResult?.success ? t("status.submitSuccess") : (message.submitResult?.message ?? t("status.submitFailed")));
             }
             if (message.type === "statusUpdate") {
                 const statuses = message.statuses ?? {};
-                setTasks((prev) => prev.map((t) => ({ ...t, status: statuses[t.value] })));
+                setTasks((prev) => prev.map((task) => ({ ...task, status: statuses[task.value] })));
             }
             if (message.type === "submissionHistory") {
                 setSubmissions(message.submissions ?? []);
                 setLoadingHistory(false);
-                setStatus(`已获取 ${(message.submissions ?? []).length} 条提交记录`);
+                setStatus(t("status.historyLoaded", { count: (message.submissions ?? []).length }));
             }
             if (message.type === "standings") {
                 const list = message.standings ?? [];
                 standingsCache.current[contest] = list;
                 setStandings(list);
                 setLoadingStandings(false);
-                setStatus(`已获取 ${list.length} 条排行`);
+                setStatus(t("status.standingsLoaded", { count: list.length }));
             }
         };
         window.addEventListener("message", handleMessage);
@@ -290,9 +292,9 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
         <div className="flex-1 overflow-y-auto p-3 space-y-3">
             <Card className="p-3 space-y-2">
                 <div className="space-y-1">
-                    <div className="text-[13px] font-semibold">{contestTitle || `比赛 ${contest}`}</div>
-                    <div className="text-[12px] opacity-70">比赛代号：{contest}</div>
-                    <div className="text-[12px] opacity-70">评级比赛：{rated ? "是" : "否"}</div>
+                    <div className="text-[13px] font-semibold">{contestTitle || t("ui.contest", { contest })}</div>
+                    <div className="text-[12px] opacity-70">{t("ui.contestId", { contest })}</div>
+                    <div className="text-[12px] opacity-70">{t("ui.isRated", { rated: rated ? t("ui.yes") : t("ui.no") })}</div>
                 </div>
                 <div className="flex items-center gap-2">
                     <Button
@@ -301,9 +303,9 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
                         variant={signed ? "secondary" : "primary"}
                         size="sm"
                         className="h-[28px] text-[12px]"
-                        title={!hasCookie ? "请先设置 AtCoder Cookie" : signed ? "已报名" : "报名比赛"}
+                        title={!hasCookie ? t("ui.setCookieFirst") : signed ? t("ui.registered") : t("ui.registerButton")}
                     >
-                        {signed ? "已报名" : "报名比赛"}
+                        {signed ? t("ui.registered") : t("ui.registerButton")}
                     </Button>
                     {rated && (
                         <label className="flex items-center gap-1 text-[12px] select-none cursor-pointer">
@@ -313,7 +315,7 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
                                 onChange={(e) => setIsRated(e.target.checked)}
                                 className="w-3 h-3"
                             />
-                            评级报名
+                            {t("ui.ratedRegistration")}
                         </label>
                     )}
                 </div>
@@ -326,7 +328,7 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
 
             {announcement && (
                 <Card className="p-3 space-y-2">
-                    <div className="text-[12px] font-semibold">公告</div>
+                    <div className="text-[12px] font-semibold">{t("ui.announcement")}</div>
                     <HtmlContent html={announcement} />
                 </Card>
             )}
@@ -337,7 +339,7 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
         <div className="flex-1 overflow-y-auto p-3 space-y-3">
             {tasks.length > 0 && (
                 <Card className="p-3 space-y-2">
-                    <div className="text-[13px] font-semibold">题目列表</div>
+                    <div className="text-[13px] font-semibold">{t("ui.taskList")}</div>
                     <div className="flex flex-wrap gap-2">
                         {tasks.map((task) => (
                             <Button
@@ -371,68 +373,68 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
                         </div>
                         <div className="flex flex-wrap gap-2 items-center">
                             <Button onClick={doTranslate} disabled={translating} size="sm" className="h-[26px] text-[11px]">
-                                {translating ? "翻译中..." : "翻译"}
+                                {translating ? t("ui.translating") : t("ui.translate")}
                             </Button>
                             <select
                                 value={translationMode}
                                 onChange={(e) => setTranslationMode(e.target.value as "api" | "free")}
                                 className="h-[26px] text-[11px] px-1 rounded border border-[var(--vscode-input-border,#6e7681)] bg-[var(--vscode-input-background)] text-[var(--vscode-input-foreground)] outline-none"
-                                title="翻译模式"
+                                title={t("ui.translationMode")}
                             >
-                                <option value="free">免费</option>
-                                <option value="api">API</option>
+                                <option value="free">{t("ui.free")}</option>
+                                <option value="api">{t("ui.api")}</option>
                             </select>
                             <Button onClick={doCopyMarkdown} size="sm" variant="secondary" className="h-[26px] text-[11px]">
-                                复制 Markdown
+                                {t("ui.copyMarkdown")}
                             </Button>
                             <Button
                                 onClick={doExportToCph}
                                 size="sm"
                                 variant="secondary"
                                 className="h-[26px] text-[11px]"
-                                title="导出到 CPH（需已安装 Competitive Programming Helper）"
+                                title={t("ui.exportCphTitle")}
                             >
-                                导出 CPH
+                                {t("ui.exportCph")}
                             </Button>
                         </div>
                     </div>
 
                     {problem.statement && (
                         <div className="space-y-1">
-                            <div className="text-[12px] font-semibold">题面</div>
+                            <div className="text-[12px] font-semibold">{t("ui.statement")}</div>
                             <HtmlContent html={problem.statement} />
-                            {translated?.["题目描述"] && (
-                                <TranslatedBlock original={problem.statement} translation={translated["题目描述"]} />
+                            {translated?.[t("text.problemStatement")] && (
+                                <TranslatedBlock original={problem.statement} translation={translated[t("text.problemStatement")]} />
                             )}
                         </div>
                     )}
 
                     {problem.constraints && (
                         <div className="space-y-1">
-                            <div className="text-[12px] font-semibold">约束</div>
+                            <div className="text-[12px] font-semibold">{t("text.constraints")}</div>
                             <HtmlContent html={problem.constraints} />
-                            {translated?.["约束"] && (
-                                <TranslatedBlock original={problem.constraints} translation={translated["约束"]} />
+                            {translated?.[t("text.constraints")] && (
+                                <TranslatedBlock original={problem.constraints} translation={translated[t("text.constraints")]} />
                             )}
                         </div>
                     )}
 
                     {problem.inputFormat && (
                         <div className="space-y-1">
-                            <div className="text-[12px] font-semibold">输入格式</div>
+                            <div className="text-[12px] font-semibold">{t("text.inputFormat")}</div>
                             <HtmlContent html={problem.inputFormat} />
-                            {translated?.["输入格式"] && (
-                                <TranslatedBlock original={problem.inputFormat} translation={translated["输入格式"]} />
+                            {translated?.[t("text.inputFormat")] && (
+                                <TranslatedBlock original={problem.inputFormat} translation={translated[t("text.inputFormat")]} />
                             )}
                         </div>
                     )}
 
                     {problem.outputFormat && (
                         <div className="space-y-1">
-                            <div className="text-[12px] font-semibold">输出格式</div>
+                            <div className="text-[12px] font-semibold">{t("text.outputFormat")}</div>
                             <HtmlContent html={problem.outputFormat} />
-                            {translated?.["输出格式"] && (
-                                <TranslatedBlock original={problem.outputFormat} translation={translated["输出格式"]} />
+                            {translated?.[t("text.outputFormat")] && (
+                                <TranslatedBlock original={problem.outputFormat} translation={translated[t("text.outputFormat")]} />
                             )}
                         </div>
                     )}
@@ -440,14 +442,14 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
                     {problem.samples?.length > 0 ? (
                         problem.samples.map((sample: SampleCase) => (
                             <div key={sample.index} className="space-y-2">
-                                <div className="text-[12px] font-semibold">Sample {sample.index}</div>
+                                <div className="text-[12px] font-semibold">{t("ui.sampleLabel", { index: sample.index })}</div>
                                 <div className="rounded bg-[var(--vscode-input-background)] p-2 relative group">
                                     <div className="text-[11px] opacity-60 mb-1">Input</div>
                                     <pre className="text-[12px] whitespace-pre-wrap break-words">{sample.input}</pre>
                                     <button
                                         onClick={() => copySampleText(`${sample.index}-in`, sample.input)}
                                         className="absolute top-1 right-1 opacity-0 group-hover:opacity-100 transition-opacity duration-200 w-5 h-5 flex items-center justify-center rounded hover:bg-[var(--vscode-toolbar-hoverBackground)]"
-                                        title="复制 Input"
+                                        title={t("ui.copyInput")}
                                     >
                                         <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="var(--vscode-editor-foreground)" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round"><rect x="9" y="9" width="13" height="13" rx="2" ry="2"/><path d="M5 15H4a2 2 0 0 1-2-2V4a2 2 0 0 1 2-2h9a2 2 0 0 1 2 2v1"/></svg>
                                     </button>
@@ -458,7 +460,7 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
                                     <button
                                         onClick={() => copySampleText(`${sample.index}-out`, sample.output)}
                                         className="absolute top-1 right-1 opacity-0 group-hover:opacity-100 transition-opacity duration-200 w-5 h-5 flex items-center justify-center rounded hover:bg-[var(--vscode-toolbar-hoverBackground)]"
-                                        title="复制 Output"
+                                        title={t("ui.copyOutput")}
                                     >
                                         <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="var(--vscode-editor-foreground)" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round"><rect x="9" y="9" width="13" height="13" rx="2" ry="2"/><path d="M5 15H4a2 2 0 0 1-2-2V4a2 2 0 0 1 2-2h9a2 2 0 0 1 2 2v1"/></svg>
                                     </button>
@@ -467,31 +469,31 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
                         ))
                     ) : problem.sampleUrl ? (
                         <div className="flex flex-col items-start gap-2">
-                            <div className="text-[12px] opacity-60">该题目没有内嵌样例，样例在外部链接中。</div>
+                            <div className="text-[12px] opacity-60">{t("ui.sampleExternal")}</div>
                             <Button
                                 onClick={() => vscode.postMessage({ command: "openBrowser", url: problem.sampleUrl! })}
                                 size="sm"
                                 className="h-[26px] text-[11px]"
                             >
-                                查看样例
+                                {t("ui.viewSamples")}
                             </Button>
                         </div>
                     ) : (
-                        <div className="text-[12px] opacity-60">当前题目没有找到样例。</div>
+                        <div className="text-[12px] opacity-60">{t("ui.noSamples")}</div>
                     )}
                 </Card>
             )}
 
             {!isLoading && tasks.length === 0 && (
                 <div className="flex flex-col items-center justify-center h-full text-[12px] opacity-60">
-                    {status || `暂无 ${contest} 的题目`}
+                    {status || t("ui.noTasks", { contest })}
                 </div>
             )}
 
             {isLoading && (
                 <div className="flex items-center gap-2 text-[12px] opacity-70">
                     <Spinner size="sm" />
-                    <span>正在抓取数据...</span>
+                    <span>{t("ui.fetchingData")}</span>
                 </div>
             )}
         </div>
@@ -501,19 +503,19 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
         <div className="flex-1 overflow-y-auto p-3 space-y-3">
             <Card className="p-3 space-y-3">
                 <div className="flex items-center justify-between flex-wrap gap-1">
-                    <div className="text-[13px] font-semibold">提交代码到 {contest}</div>
+                    <div className="text-[13px] font-semibold">{t("ui.submitTo", { contest })}</div>
                     <div className="flex gap-1 items-center">
                         <Button
                             onClick={() => vscode.postMessage({ command: "openBrowser", url: `https://atcoder.jp/contests/${contest}/submit` })}
                             size="sm"
                             variant="secondary"
                             className="h-[26px] text-[11px]"
-                            title="在浏览器中打开提交页（如遇 Cloudflare 验证可在浏览器中完成）"
+                            title={t("ui.openInBrowser")}
                         >
-                            浏览器打开
+                            {t("ui.browserOpen")}
                         </Button>
                         <Button onClick={handleFetchSubmitPage} disabled={isLoading} size="sm" className="h-[26px] text-[11px]">
-                            {submitTasks.length === 0 ? (isLoading ? "获取中..." : "获取提交页面") : "刷新"}
+                            {submitTasks.length === 0 ? (isLoading ? t("ui.fetching") : t("ui.fetchSubmitPage")) : t("ui.refresh")}
                         </Button>
                     </div>
                 </div>
@@ -526,15 +528,15 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
                             size="sm"
                             className="h-[26px] text-[11px]"
                         >
-                            在浏览器中打开提交页
+                            {t("ui.openSubmitPage")}
                         </Button>
                     </div>
                 ) : submitTasks.length === 0 && submitLanguages.length === 0 ? (
-                    <div className="text-[12px] opacity-60">点击「获取提交页面」开始提交。</div>
+                    <div className="text-[12px] opacity-60">{t("ui.clickToStart")}</div>
                 ) : (
                     <div className="space-y-3">
                         <div className="space-y-1">
-                            <div className="text-[11px] font-semibold">题目</div>
+                            <div className="text-[11px] font-semibold">{t("ui.task")}</div>
                             <select
                                 value={selectedSubmitTask}
                                 onChange={(e) => setSelectedSubmitTask(e.target.value)}
@@ -547,7 +549,7 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
                         </div>
 
                         <div className="space-y-1">
-                            <div className="text-[11px] font-semibold">语言</div>
+                            <div className="text-[11px] font-semibold">{t("ui.language")}</div>
                             <select
                                 value={selectedSubmitLanguage}
                                 onChange={(e) => setSelectedSubmitLanguage(e.target.value)}
@@ -560,11 +562,11 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
                         </div>
 
                         <div className="space-y-1">
-                            <div className="text-[11px] font-semibold">源代码</div>
+                            <div className="text-[11px] font-semibold">{t("ui.sourceCode")}</div>
                             <textarea
                                 value={sourceCode}
                                 onChange={(e) => setSourceCode(e.target.value)}
-                                placeholder="在此粘贴或输入代码..."
+                                placeholder={t("ui.codePlaceholder")}
                                 rows={10}
                                 className="w-full text-[12px] p-2 rounded border border-[var(--vscode-input-border,#6e7681)] bg-[var(--vscode-input-background)] text-[var(--vscode-input-foreground)] outline-none focus:border-[var(--vscode-focusBorder)] resize-vertical font-mono"
                             />
@@ -576,12 +578,12 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
                             size="sm"
                             className="h-[28px] text-[12px]"
                         >
-                            {isLoading ? "提交中..." : "提交"}
+                            {isLoading ? t("ui.submitting") : t("ui.submit")}
                         </Button>
 
                         {submitResult && (
                             <div className={`text-[12px] p-2 rounded ${submitResult.success ? "bg-green-500/10 text-green-500" : "bg-red-500/10 text-red-500"}`}>
-                                <div className="font-semibold mb-1">{submitResult.success ? "提交成功" : "提交失败"}</div>
+                                <div className="font-semibold mb-1">{submitResult.success ? t("ui.submitSuccessTitle") : t("ui.submitFailedTitle")}</div>
                                 <div>{submitResult.message}</div>
                                 {submitResult.url && (
                                     <div className="mt-1">
@@ -590,7 +592,7 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
                                             onClick={(e) => { e.preventDefault(); vscode.postMessage({ command: "openBrowser", url: submitResult.url }); }}
                                             className="underline"
                                         >
-                                            查看提交记录
+                                            {t("ui.viewSubmissionHistory")}
                                         </a>
                                     </div>
                                 )}
@@ -602,14 +604,14 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
 
             <Card className="p-3 space-y-2">
                 <div className="flex items-center justify-between">
-                    <div className="text-[12px] font-semibold">提交记录</div>
+                    <div className="text-[12px] font-semibold">{t("ui.submitHistoryTitle")}</div>
                     <Button onClick={handleFetchHistory} disabled={loadingHistory} size="sm" className="h-[24px] text-[11px]">
-                        {loadingHistory ? "刷新中..." : "刷新"}
+                        {loadingHistory ? t("ui.refreshing") : t("ui.refresh")}
                     </Button>
                 </div>
                 {submissions.length === 0 ? (
                     <div className="text-[12px] opacity-60">
-                        {loadingHistory ? "正在获取提交记录..." : "暂无提交记录"}
+                        {loadingHistory ? t("ui.loadingHistory") : t("ui.noHistory")}
                     </div>
                 ) : (
                     <div className="space-y-1 max-h-[300px] overflow-y-auto">
@@ -623,14 +625,14 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
                                     onClick={() => vscode.postMessage({ command: "openSubmission", contest, id: s.id })}
                                     className="text-[11px] underline opacity-60 hover:opacity-100 flex-shrink-0"
                                 >
-                                    详情
+                                    {t("ui.details")}
                                 </button>
                                 <a
                                     href="#"
                                     onClick={(e) => { e.preventDefault(); vscode.postMessage({ command: "openBrowser", url: `https://atcoder.jp/contests/${contest}/submissions/${s.id}` }); }}
                                     className="text-[11px] underline opacity-60 hover:opacity-100 flex-shrink-0"
                                 >
-                                    查看
+                                    {t("ui.view")}
                                 </a>
                             </div>
                         ))}
@@ -643,27 +645,27 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
     const renderRatingTab = () => (
         <div className="flex-1 overflow-y-auto p-3 space-y-3">
             <div className="flex items-center justify-between">
-                <div className="text-[13px] font-semibold">排行榜 - {contest}</div>
+                <div className="text-[13px] font-semibold">{t("ui.standingsTitle", { contest })}</div>
                 <Button
                     onClick={() => {
                         setLoadingStandings(true);
-                        setStatus(`正在获取 ${contest} 排行榜...`);
+                        setStatus(t("status.fetchingStandings", { contest }));
                         vscode.postMessage({ command: "fetchStandings", contest });
                     }}
                     disabled={loadingStandings}
                     size="sm"
                     className="h-[26px] text-[11px]"
                 >
-                    {loadingStandings ? "刷新中..." : "刷新"}
+                    {loadingStandings ? t("ui.refreshing") : t("ui.refresh")}
                 </Button>
             </div>
             {loadingStandings && standings.length === 0 ? (
                 <div className="flex items-center gap-2 text-[12px] opacity-70">
                     <Spinner size="sm" />
-                    <span>正在获取排行榜...</span>
+                    <span>{t("ui.fetchingStandings")}</span>
                 </div>
             ) : standings.length === 0 ? (
-                <div className="text-[12px] opacity-60">暂无排行数据</div>
+                <div className="text-[12px] opacity-60">{t("ui.noStandings")}</div>
             ) : (
                 <div className="space-y-1">
                     {standings.map((row) => (
@@ -690,7 +692,7 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
             <div className="h-[35px] flex items-center px-3 bg-[var(--vscode-titleBar-activeBackground)] text-[var(--vscode-titleBar-activeForeground)]">
                 <span className="text-[13px] select-none truncate">AtCoder - {contest}</span>
                 {hasCookie && (
-                    <span className="ml-2 w-2 h-2 rounded-full bg-green-500" title="已登录 AtCoder" />
+                    <span className="ml-2 w-2 h-2 rounded-full bg-green-500" title={t("cookie.loggedIn")} />
                 )}
             </div>
             <div className="flex border-b border-[var(--vscode-panel-border)]">
@@ -700,7 +702,7 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
                         onClick={() => openTab(tab.key)}
                         className={`flex-1 h-[30px] text-[12px] border-b-2 transition-colors ${activeTab === tab.key ? "border-[var(--vscode-focusBorder)] text-[var(--vscode-foreground)]" : "border-transparent opacity-60 hover:opacity-100"}`}
                     >
-                        {tab.label}
+                        {t(tab.label)}
                     </button>
                 ))}
             </div>
@@ -708,19 +710,19 @@ const ContestApp: React.FC<ContestAppProps> = ({ initContest = "" }) => {
             {cfUrl && (
                 <div className="absolute inset-0 z-10 flex items-center justify-center bg-[var(--vscode-editor-background)]/80">
                     <div className="p-6 flex flex-col items-center justify-center gap-4 max-w-md text-center">
-                        <div className="text-[14px] font-medium text-yellow-600">Cloudflare 验证</div>
+                        <div className="text-[14px] font-medium text-yellow-600">{t("ui.cfTitle")}</div>
                         <div className="text-[12px] opacity-70">
-                            AtCoder 触发了 Cloudflare 验证，插件无法直接访问。请点击下方按钮在浏览器中打开，完成验证后重新设置 Cookie 再试。
+                            {t("ui.cfContestBody")}
                         </div>
                         <div className="flex gap-3 mt-2 flex-wrap justify-center">
                             <Button
                                 onClick={() => vscode.postMessage({ command: "openBrowser", url: cfUrl })}
                                 className="h-[32px] text-[12px]"
                             >
-                                在浏览器中打开
+                                {t("ui.openInBrowser")}
                             </Button>
                             <Button onClick={() => setCfUrl(null)} variant="secondary" className="h-[32px] text-[12px]">
-                                关闭
+                                {t("ui.close")}
                             </Button>
                         </div>
                     </div>
diff --git a/packages/webview/src/SidebarApp.tsx b/packages/webview/src/SidebarApp.tsx
index fb4684e..11033fa 100644
--- a/packages/webview/src/SidebarApp.tsx
+++ b/packages/webview/src/SidebarApp.tsx
@@ -1,13 +1,14 @@
 import React from "react";
 import { Button, Spinner } from "@template/ui";
 import { useVSCode } from "./VSCodeProvider";
+import { useI18n } from "./i18n";
 import type { HomepageContest, SubmissionRecord, WebviewMessage } from "./types";
 
-const CATEGORY_GROUPS: Array<{ key: HomepageContest["category"]; label: string }> = [
-    { key: "active", label: "进行中" },
-    { key: "upcoming", label: "即将开始" },
-    { key: "recent", label: "最近" },
-    { key: "daily", label: "每日" },
+const CATEGORY_GROUPS: Array<{ key: HomepageContest["category"] }> = [
+    { key: "active" },
+    { key: "upcoming" },
+    { key: "recent" },
+    { key: "daily" },
 ];
 
 const statusColor = (status: string): string => {
@@ -38,6 +39,7 @@ const formatSubmitTime = (time: string): string => {
 
 const SidebarApp: React.FC = () => {
     const vscode = useVSCode();
+    const { t, nodes } = useI18n();
     const [contests, setContests] = React.useState<HomepageContest[]>([]);
     const [currentContest, setCurrentContest] = React.useState<string | null>(null);
     const [submissions, setSubmissions] = React.useState<SubmissionRecord[]>([]);
@@ -52,30 +54,30 @@ const SidebarApp: React.FC = () => {
 
     const fetchContests = () => {
         setLoadingList(true);
-        setStatus("正在抓取 AtCoder 首页比赛列表...");
+        setStatus(t("status.fetchingHomepage"));
         vscode.postMessage({ command: "getContests" });
     };
 
     const handleCookieSave = () => {
         const val = cookieInput.trim();
         if (!val) {
-            setStatus("请先复制 REVEL_SESSION 的值再保存");
+            setStatus(t("cookie.pasteFirst"));
             return;
         }
         const finalVal = val.startsWith("REVEL_SESSION=") ? val : `REVEL_SESSION=${val}`;
         setCookieInput("");
-        setStatus("Cookie 已保存");
+        setStatus(t("cookie.saved"));
         vscode.postMessage({ command: "setCookie", text: finalVal });
     };
 
     const handleCookieClear = () => {
         vscode.postMessage({ command: "setCookie", text: "" });
-        setStatus("Cookie 已清除");
+        setStatus(t("cookie.cleared"));
     };
 
     const fetchHistory = (contest: string) => {
         setLoadingHistory(true);
-        setStatus(`正在获取 ${contest} 的提交记录...`);
+        setStatus(t("status.fetchingHistory", { contest }));
         vscode.postMessage({ command: "fetchSubmissionHistory", contest });
     };
 
@@ -96,12 +98,12 @@ const SidebarApp: React.FC = () => {
             if (message.type === "contestList") {
                 setContests(message.contests ?? []);
                 setLoadingList(false);
-                setStatus(`已获取 ${(message.contests ?? []).length} 场比赛`);
+                setStatus(t("status.homepageLoaded", { count: (message.contests ?? []).length }));
             }
             if (message.type === "submissionHistory") {
                 setSubmissions(message.submissions ?? []);
                 setLoadingHistory(false);
-                setStatus(`已获取 ${(message.submissions ?? []).length} 条提交记录`);
+                setStatus(t("status.historyLoaded", { count: (message.submissions ?? []).length }));
             }
             if (message.type === "loading" || message.type === "update") {
                 setStatus(message.text ?? "");
@@ -114,7 +116,7 @@ const SidebarApp: React.FC = () => {
                         setCookieInput("");
                     }
                 }
-                setStatus("Cookie 已更新，正在刷新...");
+                setStatus(t("cookie.updated"));
                 fetchContests();
                 if (currentContestRef.current) {
                     fetchHistory(currentContestRef.current);
@@ -131,10 +133,10 @@ const SidebarApp: React.FC = () => {
             }
             if (message.type === "loginRequired") {
                 setShowLogin(true);
-                setStatus("需要登录 AtCoder 账号才能使用该功能");
+                setStatus(t("cookie.loginRequired"));
             }
             if (message.type === "error") {
-                setStatus(message.text ?? "操作失败");
+                setStatus(message.text ?? t("err.operationFailed"));
                 setLoadingList(false);
                 setLoadingHistory(false);
             }
@@ -161,11 +163,11 @@ const SidebarApp: React.FC = () => {
         <div className="h-screen flex flex-col bg-[var(--vscode-sideBar-background)] text-[var(--vscode-sideBar-foreground)]">
             {(showLogin || hasCookie === false) && (
                 <div className="p-2 space-y-2 border-b border-[var(--vscode-panel-border)] bg-[var(--vscode-textBlockQuote-background)]">
-                    <div className="text-[12px] font-semibold">需要登录 AtCoder 账号</div>
+                    <div className="text-[12px] font-semibold">{t("cookie.loginTitle")}</div>
                     <div className="text-[11px] opacity-70 leading-relaxed">
-                        提交记录、排行榜等需要登录。请在浏览器登录 AtCoder，按 F12 → Application → Cookies 复制{" "}
-                        <code className="bg-[var(--vscode-textBlockQuote-background)] px-1 rounded">REVEL_SESSION</code>{" "}
-                        的 Value 粘贴到下方。
+                        {nodes(t("cookie.loginDesc"), {
+                            code: <code className="bg-[var(--vscode-textBlockQuote-background)] px-1 rounded">REVEL_SESSION</code>,
+                        })}
                     </div>
                     <div className="flex gap-1">
                         <input
@@ -173,40 +175,40 @@ const SidebarApp: React.FC = () => {
                             value={cookieInput}
                             onChange={(e) => setCookieInput(e.target.value)}
                             onKeyDown={(e) => e.key === "Enter" && handleCookieSave()}
-                            placeholder={hasCookie ? "已保存 Cookie，输入新值可覆盖" : "粘贴 REVEL_SESSION 的 Value"}
+                            placeholder={hasCookie ? t("cookie.placeholderHas") : t("cookie.placeholderEmpty")}
                             className="flex-1 h-[26px] text-[12px] px-2 rounded border border-[var(--vscode-input-border,#6e7681)] bg-[var(--vscode-input-background)] text-[var(--vscode-input-foreground)] outline-none focus:border-[var(--vscode-focusBorder)]"
                         />
                         <Button onClick={handleCookieSave} size="sm" disabled={!cookieInput.trim()} className="h-[26px] text-[11px] flex-shrink-0">
-                            保存
+                            {t("ui.save")}
                         </Button>
                     </div>
                     {hasCookie && (
                         <Button onClick={handleCookieClear} size="sm" variant="secondary" className="h-[24px] text-[11px]">
-                            清除 Cookie
+                            {t("cookie.clearLabel")}
                         </Button>
                     )}
                 </div>
             )}
             <div className="flex-1 flex flex-col min-h-0 border-b border-[var(--vscode-panel-border)]">
                 <div className="p-2 flex items-center justify-between border-b border-[var(--vscode-panel-border)]">
-                    <div className="text-[12px] font-semibold">比赛列表</div>
+                    <div className="text-[12px] font-semibold">{t("ui.contestsTitle")}</div>
                     <Button
                         size="sm"
                         onClick={fetchContests}
                         disabled={loadingList}
                         className="h-[24px] text-[11px] flex-shrink-0"
                     >
-                        {loadingList ? "刷新中..." : "刷新"}
+                        {loadingList ? t("ui.refreshing") : t("ui.refresh")}
                     </Button>
                 </div>
                 <div className="flex-1 overflow-y-auto">
                     {loadingList && contests.length === 0 ? (
                         <div className="p-3 flex items-center gap-2 text-[12px] opacity-70">
                             <Spinner size="sm" />
-                            <span>正在抓取比赛列表...</span>
+                            <span>{t("ui.fetchingContests")}</span>
                         </div>
                     ) : contests.length === 0 ? (
-                        <div className="p-3 text-[12px] opacity-60">暂无比赛，点击刷新</div>
+                        <div className="p-3 text-[12px] opacity-60">{t("ui.noContests")}</div>
                     ) : (
                         CATEGORY_GROUPS.map((group) => {
                             const rows = contests.filter((c) => c.category === group.key);
@@ -214,7 +216,7 @@ const SidebarApp: React.FC = () => {
                             return (
                                 <div key={group.key}>
                                     <div className="px-2 py-1 text-[10px] font-semibold opacity-60 bg-[var(--vscode-sideBarSectionHeader-background)]">
-                                        {group.label}
+                                        {t(`cat.${group.key}`)}
                                     </div>
                                     {rows.map(renderContestRow)}
                                 </div>
@@ -227,7 +229,7 @@ const SidebarApp: React.FC = () => {
             <div className="flex-1 flex flex-col min-h-0">
                 <div className="p-2 flex items-center justify-between border-b border-[var(--vscode-panel-border)]">
                     <div className="text-[12px] font-semibold truncate">
-                        提交记录{currentContest ? ` - ${currentContest}` : ""}
+                        {t("ui.submitHistoryTitle")}{currentContest ? ` - ${currentContest}` : ""}
                     </div>
                     <Button
                         size="sm"
@@ -235,19 +237,19 @@ const SidebarApp: React.FC = () => {
                         disabled={!currentContest || loadingHistory}
                         className="h-[24px] text-[11px] flex-shrink-0"
                     >
-                        {loadingHistory ? "刷新中..." : "刷新"}
+                        {loadingHistory ? t("ui.refreshing") : t("ui.refresh")}
                     </Button>
                 </div>
                 <div className="flex-1 overflow-y-auto">
                     {!currentContest ? (
-                        <div className="p-3 text-[12px] opacity-60">点击比赛查看提交记录</div>
+                        <div className="p-3 text-[12px] opacity-60">{t("ui.clickContestForHistory")}</div>
                     ) : loadingHistory && submissions.length === 0 ? (
                         <div className="p-3 flex items-center gap-2 text-[12px] opacity-70">
                             <Spinner size="sm" />
-                            <span>正在获取提交记录...</span>
+                            <span>{t("ui.loadingHistory")}</span>
                         </div>
                     ) : submissions.length === 0 ? (
-                        <div className="p-3 text-[12px] opacity-60">暂无提交记录</div>
+                        <div className="p-3 text-[12px] opacity-60">{t("ui.noHistory")}</div>
                     ) : (
                         <div className="space-y-1 p-1">
                             {submissions.map((s) => (
@@ -265,7 +267,7 @@ const SidebarApp: React.FC = () => {
                                         onClick={() => vscode.postMessage({ command: "openSubmission", contest: currentContest, id: s.id })}
                                         className="text-[11px] underline opacity-60 hover:opacity-100 flex-shrink-0"
                                     >
-                                        详情
+                                        {t("ui.details")}
                                     </button>
                                     <a
                                         href="#"
@@ -278,7 +280,7 @@ const SidebarApp: React.FC = () => {
                                         }}
                                         className="text-[11px] underline opacity-60 hover:opacity-100 flex-shrink-0"
                                     >
-                                        查看
+                                        {t("ui.view")}
                                     </a>
                                 </div>
                             ))}
diff --git a/packages/webview/src/SubmissionDetailApp.tsx b/packages/webview/src/SubmissionDetailApp.tsx
index 137c326..5d8fe57 100644
--- a/packages/webview/src/SubmissionDetailApp.tsx
+++ b/packages/webview/src/SubmissionDetailApp.tsx
@@ -1,6 +1,7 @@
 import React from "react";
 import { Button, Card, Spinner } from "@template/ui";
 import { useVSCode } from "./VSCodeProvider";
+import { useI18n } from "./i18n";
 import type { SubmissionDetail, WebviewMessage } from "./types";
 
 interface SubmissionDetailAppProps {
@@ -29,6 +30,7 @@ const statusColor = (status: string): string => {
 
 const SubmissionDetailApp: React.FC<SubmissionDetailAppProps> = ({ initContest = "", initSubmissionId = "" }) => {
     const vscode = useVSCode();
+    const { t } = useI18n();
     const [detail, setDetail] = React.useState<SubmissionDetail | null>(null);
     const [isLoading, setIsLoading] = React.useState(false);
     const [copied, setCopied] = React.useState(false);
@@ -37,11 +39,11 @@ const SubmissionDetailApp: React.FC<SubmissionDetailAppProps> = ({ initContest =
 
     const fetchDetail = () => {
         if (!initContest || !initSubmissionId) {
-            setStatus("缺少比赛代号或提交 ID");
+            setStatus(t("ui.missingContestOrId"));
             return;
         }
         setIsLoading(true);
-        setStatus(`正在获取提交 ${initSubmissionId} 的详细信息...`);
+        setStatus(t("ui.fetchingDetail"));
         vscode.postMessage({ command: "fetchSubmissionDetail", contest: initContest, id: initSubmissionId });
     };
 
@@ -62,21 +64,21 @@ const SubmissionDetailApp: React.FC<SubmissionDetailAppProps> = ({ initContest =
             if (message.type === "submissionDetail") {
                 setDetail(message.submissionDetail ?? null);
                 setIsLoading(false);
-                setStatus(`已加载提交 ${message.submissionDetail?.id ?? ""}`);
+                setStatus(t("status.detailLoaded", { id: message.submissionDetail?.id ?? "" }));
             }
             if (message.type === "loading" || message.type === "update") {
                 setStatus(message.text ?? "");
             }
             if (message.type === "error") {
-                setStatus(message.text ?? "获取提交详情失败");
+                setStatus(message.text ?? t("err.detail"));
                 setIsLoading(false);
             }
             if (message.type === "cf_challenge") {
-                setStatus("AtCoder 触发 Cloudflare 验证，请在浏览器中打开查看");
+                setStatus(t("status.cfOpenBrowser"));
                 setIsLoading(false);
             }
             if (message.type === "loginRequired") {
-                setStatus("需要登录 AtCoder 账号，请在侧边栏设置 Cookie 后再试");
+                setStatus(t("status.loginRequiredSidebar"));
                 setIsLoading(false);
             }
         };
@@ -94,7 +96,7 @@ const SubmissionDetailApp: React.FC<SubmissionDetailAppProps> = ({ initContest =
     return (
         <div className="h-screen flex flex-col bg-[var(--vscode-editor-background)] text-[var(--vscode-editor-foreground)]">
             <div className="h-[35px] flex items-center px-3 bg-[var(--vscode-titleBar-activeBackground)] text-[var(--vscode-titleBar-activeForeground)]">
-                <span className="text-[13px] select-none truncate">提交 {initSubmissionId} - {initContest}</span>
+                <span className="text-[13px] select-none truncate">{t("ui.submissionTitle", { id: initSubmissionId, contest: initContest })}</span>
                 <div className="ml-auto flex items-center gap-1">
                     <Button
                         onClick={fetchDetail}
@@ -102,7 +104,7 @@ const SubmissionDetailApp: React.FC<SubmissionDetailAppProps> = ({ initContest =
                         size="sm"
                         className="h-[24px] text-[11px]"
                     >
-                        {isLoading ? "刷新中..." : "刷新"}
+                        {isLoading ? t("ui.refreshing") : t("ui.refresh")}
                     </Button>
                     <Button
                         onClick={() => vscode.postMessage({ command: "openBrowser", url: `https://atcoder.jp/contests/${initContest}/submissions/${initSubmissionId}` })}
@@ -110,7 +112,7 @@ const SubmissionDetailApp: React.FC<SubmissionDetailAppProps> = ({ initContest =
                         variant="secondary"
                         className="h-[24px] text-[11px]"
                     >
-                        浏览器打开
+                        {t("ui.browserOpen")}
                     </Button>
                 </div>
             </div>
@@ -119,10 +121,10 @@ const SubmissionDetailApp: React.FC<SubmissionDetailAppProps> = ({ initContest =
                 {isLoading && !detail ? (
                     <div className="flex items-center gap-2 text-[12px] opacity-70">
                         <Spinner size="sm" />
-                        <span>正在获取提交详情...</span>
+                        <span>{t("ui.fetchingDetail")}</span>
                     </div>
                 ) : !detail ? (
-                    <div className="text-[12px] opacity-60">{status || "无提交详情"}</div>
+                    <div className="text-[12px] opacity-60">{status || t("ui.noDetail")}</div>
                 ) : (
                     <>
                         <Card className="p-3 space-y-2">
@@ -133,26 +135,26 @@ const SubmissionDetailApp: React.FC<SubmissionDetailAppProps> = ({ initContest =
                                 </span>
                             </div>
                             <div className="grid grid-cols-2 gap-x-4 gap-y-1">
-                                {renderMeta("提交时间", detail.time)}
-                                {renderMeta("得分", detail.score)}
-                                {renderMeta("语言", detail.language)}
-                                {renderMeta("代码长度", detail.codeLength)}
-                                {renderMeta("执行时间", detail.execTime)}
-                                {renderMeta("内存", detail.memory)}
+                                {renderMeta(t("ui.submitTime"), detail.time)}
+                                {renderMeta(t("ui.score"), detail.score)}
+                                {renderMeta(t("ui.language"), detail.language)}
+                                {renderMeta(t("ui.codeLength"), detail.codeLength)}
+                                {renderMeta(t("ui.execTime"), detail.execTime)}
+                                {renderMeta(t("ui.memory"), detail.memory)}
                             </div>
                         </Card>
 
                         {detail.judgeSets && detail.judgeSets.length > 0 && (
                             <Card className="p-3 space-y-2">
                                 <div className="flex items-center justify-between">
-                                    <div className="text-[12px] font-semibold">测试点</div>
+                                    <div className="text-[12px] font-semibold">{t("ui.testPoints")}</div>
                                     <Button
                                         onClick={() => setShowJudgeSets((v) => !v)}
                                         size="sm"
                                         variant="secondary"
                                         className="h-[24px] text-[11px]"
                                     >
-                                        {showJudgeSets ? "收起" : "展开"}
+                                        {showJudgeSets ? t("ui.collapse") : t("ui.expand")}
                                     </Button>
                                 </div>
                                 {showJudgeSets && (
@@ -204,9 +206,9 @@ const SubmissionDetailApp: React.FC<SubmissionDetailAppProps> = ({ initContest =
 
                         <Card className="p-3 space-y-2">
                             <div className="flex items-center justify-between">
-                                <div className="text-[12px] font-semibold">源代码</div>
+                                <div className="text-[12px] font-semibold">{t("ui.sourceCode")}</div>
                                 <Button onClick={copyCode} size="sm" variant="secondary" className="h-[24px] text-[11px]">
-                                    {copied ? "已复制" : "复制"}
+                                    {copied ? t("ui.copied") : t("ui.copy")}
                                 </Button>
                             </div>
                             <pre className="text-[12px] leading-relaxed whitespace-pre-wrap break-words font-mono bg-[var(--vscode-input-background)] p-2 rounded">
diff --git a/packages/webview/src/WebviewApp.tsx b/packages/webview/src/WebviewApp.tsx
index 8459352..c248055 100644
--- a/packages/webview/src/WebviewApp.tsx
+++ b/packages/webview/src/WebviewApp.tsx
@@ -3,6 +3,7 @@ import { Button, Card, Input, Spinner } from "@template/ui";
 import "./styles.css";
 
 import { useVSCode } from "./VSCodeProvider";
+import { useI18n } from "./i18n";
 import type { WebviewMessage, ContestProblem, SampleCase, SubmitResult } from "./types";
 import { HtmlContent, TranslatedBlock } from "./components/HtmlContent";
 
@@ -14,11 +15,12 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
   title = "VSCode Extension",
 }) => {
   const vscode = useVSCode();
+  const { t, nodes } = useI18n();
   const [contest, setContest] = React.useState("");
   const [tasks, setTasks] = React.useState<Array<{ label: string; value: string; url: string; status?: string }>>([]);
   const [selectedTask, setSelectedTask] = React.useState<string>("");
   const [problem, setProblem] = React.useState<ContestProblem | null>(null);
-  const [status, setStatus] = React.useState("输入比赛代号并加载题目列表");
+  const [status, setStatus] = React.useState(t("ui.enterContestHint"));
   const [isLoading, setIsLoading] = React.useState(false);
   const [cfUrl, setCfUrl] = React.useState<string | null>(null);
   const [translated, setTranslated] = React.useState<Record<string, string> | null>(null);
@@ -48,44 +50,44 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
 
   const loadContest = async (nextContest: string) => {
     setIsLoading(true);
-    setStatus(`正在加载 ${nextContest} 的题目...`);
+    setStatus(t("status.loadingContest", { contest: nextContest }));
     vscode.postMessage({ command: "loadContest", contest: nextContest });
   };
 
   const loadProblem = async (nextContest: string, task: string) => {
     setIsLoading(true);
-    setStatus(`正在抓取 ${nextContest}/${task} 的题面...`);
+    setStatus(t("status.fetchingProblem", { contest: nextContest, task }));
     setTranslated(translatedCache[task] ?? null);
     vscode.postMessage({ command: "loadProblem", contest: nextContest, task });
   };
 
   const handleRegister = () => {
     setRegistrationMessage(null);
-    setStatus(`正在报名 ${contest} ...`);
+    setStatus(t("status.registration", { contest }));
     vscode.postMessage({ command: "registerContest", contest, rated: isRated });
   };
 
   const doCopyMarkdown = () => {
     if (!problem) return;
     vscode.postMessage({ command: "copyMarkdown", problem });
-    setStatus("正在复制...");
+    setStatus(t("status.copying"));
   };
 
   const doTranslate = () => {
     if (!problem) return;
     setTranslating(true);
-    setStatus("正在翻译...");
+    setStatus(t("status.translating"));
     const texts: Record<string, string> = {};
-    if (problem.statement) texts["题目描述"] = problem.statement;
-    if (problem.constraints) texts["约束"] = problem.constraints;
-    if (problem.inputFormat) texts["输入格式"] = problem.inputFormat;
-    if (problem.outputFormat) texts["输出格式"] = problem.outputFormat;
+    if (problem.statement) texts[t("text.problemStatement")] = problem.statement;
+    if (problem.constraints) texts[t("text.constraints")] = problem.constraints;
+    if (problem.inputFormat) texts[t("text.inputFormat")] = problem.inputFormat;
+    if (problem.outputFormat) texts[t("text.outputFormat")] = problem.outputFormat;
     vscode.postMessage({ command: "translate", payload: texts, targetLang: "ZH", translationMode } as WebviewMessage);
   };
 
   const doExportToCph = () => {
     if (!problem) return;
-    setStatus("正在导出到 CPH...");
+    setStatus(t("status.exportingCph"));
     vscode.postMessage({ command: "sendCph", problem });
   };
 
@@ -94,7 +96,7 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
     setSubmitTasks([]);
     setSubmitLanguages([]);
     setSourceCode("");
-    setStatus("正在获取提交页面...");
+    setStatus(t("status.fetchingSubmitPage"));
     vscode.postMessage({ command: "fetchSubmitPage", contest });
   };
 
@@ -106,14 +108,14 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
 
   const handleFetchSubmissionHistory = () => {
     setLoadingHistory(true);
-    setStatus("正在获取提交记录...");
+    setStatus(t("status.fetchingHistory"));
     vscode.postMessage({ command: "fetchSubmissionHistory", contest } as unknown as WebviewMessage);
   };
 
   const handleSubmitCode = () => {
     if (!selectedSubmitTask || !selectedSubmitLanguage || !sourceCode.trim()) return;
     setSubmitResult(null);
-    setStatus("正在提交代码...");
+    setStatus(t("status.submitting"));
     vscode.postMessage({
       command: "submitCode",
       contest,
@@ -144,7 +146,7 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
         setSelectedTask("");
         setProblem(null);
         setRated(true);
-        setStatus(`已加载 ${nextTasks.length} 道题目`);
+        setStatus(t("status.tasksLoaded", { count: nextTasks.length }));
         setIsLoading(false);
       }
       if (message.type === "contestInfo") {
@@ -152,37 +154,37 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
       }
       if (message.type === "problem") {
         setProblem(message.problem ?? null);
-        setStatus(`已加载题面：${message.problem?.title ?? ""}`);
+        setStatus(t("status.problemLoaded", { title: message.problem?.title ?? "" }));
         setIsLoading(false);
       }
       if (message.type === "loading" || message.type === "update") {
-        setStatus(message.text ?? "加载中...");
+        setStatus(message.text ?? t("status.loading"));
       }
       if (message.type === "error") {
-        setStatus(message.text ?? "操作失败");
+        setStatus(message.text ?? t("err.operationFailed"));
         setIsLoading(false);
         setTranslating(false);
       }
       if (message.type === "cphExportResult") {
         const ok = message.success === true;
-        setStatus(ok ? (message.message ?? "已发送到 CPH") : (message.message ?? "导出到 CPH 失败"));
+        setStatus(ok ? (message.message ?? t("status.sentToCph")) : (message.message ?? t("status.cphExportFailed")));
         setIsLoading(false);
       }
       if (message.type === "cf_challenge") {
         setCfUrl(message.url ?? null);
         setIsLoading(false);
-        setStatus("AtCoder 触发 Cloudflare 验证，插件无法直接访问，请在浏览器中使用");
+        setStatus(t("status.cfChallenge"));
       }
       if (message.type === "loginRequired") {
         setIsLoading(false);
         setShowSettings(true);
-        setStatus("需要登录 AtCoder 才能查看。请在浏览器中登录，然后将 Cookie 粘贴到设置中");
+        setStatus(t("status.loginRequired"));
       }
       if (message.type === "translation") {
         setTranslatedCache(prev => ({ ...prev, [selectedTaskRef.current]: message.translated ?? {} }));
         setTranslated(message.translated ?? null);
         setTranslating(false);
-        setStatus("翻译完成");
+        setStatus(t("status.translationDone"));
       }
       if (message.type === "cookieStatus") {
         setHasCookie(message.hasCookie ?? false);
@@ -198,7 +200,7 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
       if (message.type === "registrationStatus") {
         setSigned(message.signed ?? false);
         setRegistrationMessage(message.registrationMessage ?? null);
-        setStatus(message.registrationMessage ?? (message.signed ? "报名成功" : "报名失败"));
+        setStatus(message.registrationMessage ?? (message.signed ? t("status.registrationSuccess") : t("status.registrationFail")));
         setIsLoading(false);
       }
       if (message.type === "submitPage") {
@@ -211,16 +213,16 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
           setSelectedSubmitLanguage(message.languages[0].id);
         }
         setShowSubmitPanel(true);
-        setStatus("已获取提交页面信息");
+        setStatus(t("status.submitPageReady"));
         setIsLoading(false);
       }
       if (message.type === "submitResult") {
         setSubmitResult(message.submitResult ?? null);
         setIsLoading(false);
         if (message.submitResult?.success) {
-          setStatus("代码提交成功");
+          setStatus(t("status.submitSuccess"));
         } else {
-          setStatus(message.submitResult?.message ?? "提交失败");
+          setStatus(message.submitResult?.message ?? t("status.submitFailed"));
         }
       }
       if (message.type === "statusUpdate") {
@@ -236,7 +238,7 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
         }
         setTasks(prev => prev.map(t => ({ ...t, status: latest[t.value] })));
         setLoadingHistory(false);
-        setStatus(`已获取 ${(m.submissions ?? []).length} 条提交记录`);
+        setStatus(t("status.historyLoaded", { count: (m.submissions ?? []).length }));
         setShowSubmissionHistory(true);
       }
     };
@@ -247,7 +249,7 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
 
   function getStatusColor() {
     if (isLoading) return "bg-yellow-500";
-    if (status.includes("失败") || status.includes("Error")) return "bg-red-500";
+    if (/失败|failed|error/i.test(status)) return "bg-red-500";
     if (tasks.length > 0 || problem) return "bg-green-500";
     return "bg-gray-500";
   }
@@ -264,11 +266,11 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
           <span className="text-[13px] select-none">{title}</span>
         </div>
         <div className="ml-auto flex items-center gap-1">
-          {hasCookie && <span className="w-2 h-2 rounded-full bg-green-500" title="已登录 AtCoder" />}
+          {hasCookie && <span className="w-2 h-2 rounded-full bg-green-500" title={t("cookie.loggedIn")} />}
           <button
             onClick={() => setShowSettings(!showSettings)}
             className="text-[11px] opacity-60 hover:opacity-100 px-1 py-0.5 rounded hover:bg-[var(--vscode-toolbar-hoverBackground)]"
-            title="设置"
+            title={t("ui.settings")}
           >
             ⚙
           </button>
@@ -278,17 +280,48 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
       <div className="flex-1 flex flex-col bg-[var(--vscode-editor-background)] text-[var(--vscode-editor-foreground)]">
         {showSettings && (
           <div className="p-3 border-b border-[var(--vscode-panel-border)] space-y-2 bg-[var(--vscode-textBlockQuote-background)]">
-            <div className="text-[12px] font-semibold">AtCoder 登录 Cookie</div>
+            <div className="text-[12px] font-semibold">{t("cookie.title")}</div>
             <div className="space-y-1 text-[11px] opacity-70 leading-relaxed">
-              <div>AtCoder 仅需 <code className="bg-[var(--vscode-textBlockQuote-background)] px-1 rounded">REVEL_SESSION</code> 一个 Cookie 即可登录。</div>
-              <div className="font-medium mt-1">获取步骤：</div>
+              <div>
+                {nodes(t("cookie.onlyNeedRevel"), {
+                  code: <code className="bg-[var(--vscode-textBlockQuote-background)] px-1 rounded">REVEL_SESSION</code>,
+                })}
+              </div>
+              <div className="font-medium mt-1">{t("cookie.steps")}</div>
               <ol className="list-decimal pl-4 space-y-0.5">
-                <li>在浏览器中打开 <span className="underline cursor-pointer" onClick={() => vscode.postMessage({ command: "openBrowser", url: "https://atcoder.jp/login" })}>https://atcoder.jp/login</span> 并登录</li>
-                <li>按 <kbd className="px-1 rounded border border-[var(--vscode-input-border,#6e7681)]">F12</kbd> 打开开发者工具</li>
-                <li>切换到 <b>Application</b>（Chrome）或 <b>存储</b>（Edge）标签页</li>
-                <li>左侧找到 <b>Cookies</b> → <b>https://atcoder.jp</b></li>
-                <li>找到名为 <code className="bg-[var(--vscode-textBlockQuote-background)] px-1 rounded">REVEL_SESSION</code> 的行，双击 <b>Value</b> 列全选复制</li>
-                <li>粘贴到下方输入框（无需手动加前缀，插件会自动补全）</li>
+                <li>
+                  {nodes(t("cookie.step1"), {
+                    link: (
+                      <span className="underline cursor-pointer" onClick={() => vscode.postMessage({ command: "openBrowser", url: "https://atcoder.jp/login" })}>
+                        https://atcoder.jp/login
+                      </span>
+                    ),
+                  })}
+                </li>
+                <li>
+                  {nodes(t("cookie.step2"), {
+                    key: <kbd className="px-1 rounded border border-[var(--vscode-input-border,#6e7681)]">F12</kbd>,
+                  })}
+                </li>
+                <li>
+                  {nodes(t("cookie.step3"), {
+                    application: <b>{t("cookie.chromeApp")}</b>,
+                    storage: <b>{t("cookie.edgeStorage")}</b>,
+                  })}
+                </li>
+                <li>
+                  {nodes(t("cookie.step4"), {
+                    cookies: <b>Cookies</b>,
+                    site: <b>https://atcoder.jp</b>,
+                  })}
+                </li>
+                <li>
+                  {nodes(t("cookie.step5"), {
+                    code: <code className="bg-[var(--vscode-textBlockQuote-background)] px-1 rounded">REVEL_SESSION</code>,
+                    value: <b>Value</b>,
+                  })}
+                </li>
+                <li>{t("cookie.step6")}</li>
               </ol>
             </div>
             <div className="flex items-center gap-2">
@@ -296,40 +329,40 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
                 type="password"
                 value={cookieInput}
                 onChange={(e) => setCookieInput(e.target.value)}
-                placeholder={hasCookie ? "已保存 Cookie，输入新值可覆盖" : "粘贴 REVEL_SESSION 的 Value"}
+                placeholder={hasCookie ? t("cookie.placeholderHas") : t("cookie.placeholderEmpty")}
                 className="flex-1 h-[28px] text-[12px] px-2 rounded border border-[var(--vscode-input-border,#6e7681)] bg-[var(--vscode-input-background)] text-[var(--vscode-input-foreground)] outline-none focus:border-[var(--vscode-focusBorder)]"
               />
               <Button
                 onClick={() => {
                   const val = cookieInput.trim();
                   if (!val) {
-                    setStatus("请先复制 REVEL_SESSION 的值再保存");
+                    setStatus(t("cookie.pasteFirst"));
                     return;
                   }
                   const finalVal = val.startsWith("REVEL_SESSION=") ? val : `REVEL_SESSION=${val}`;
                   setCookieInput("");
                   setHasCookie(true);
-                  setStatus("Cookie 已保存");
+                  setStatus(t("cookie.saved"));
                   vscode.postMessage({ command: "setCookie", text: finalVal });
                 }}
                 size="sm"
                 className="h-[28px] text-[11px]"
                 disabled={!cookieInput.trim()}
               >
-                保存
+                {t("ui.save")}
               </Button>
               {hasCookie && (
                   <Button
                     onClick={() => {
                       vscode.postMessage({ command: "setCookie", text: "" });
                       setHasCookie(false);
-                      setStatus("Cookie 已清除");
+                      setStatus(t("cookie.cleared"));
                     }}
                     size="sm"
                     variant="secondary"
                     className="h-[28px] text-[11px]"
                   >
-                    清除
+                    {t("ui.clear")}
                   </Button>
               )}
             </div>
@@ -342,12 +375,12 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
               value={contest}
               onChange={(e) => setContest(e.target.value)}
               onKeyDown={(e) => e.key === "Enter" && void loadContest(contest)}
-              placeholder="输入比赛代码，如 abc345"
+              placeholder={t("ui.contestPlaceholder")}
               className="flex-1 h-[28px] text-[12px] bg-white! text-[#000000]! placeholder:text-[#000000]! placeholder:opacity-100! shadow-none!"
               disabled={isLoading}
             />
             <Button onClick={() => void loadContest(contest)} disabled={isLoading} className="h-[28px] text-[12px]">
-              加载题目
+              {t("ui.loadTasks")}
             </Button>
             <Button
               onClick={handleRegister}
@@ -355,9 +388,9 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
               variant={signed ? "secondary" : "primary"}
               size="sm"
               className="h-[28px] text-[12px]"
-              title={!hasCookie ? "请先设置 AtCoder Cookie" : signed ? "已报名" : "报名比赛"}
+              title={!hasCookie ? t("ui.setCookieFirst") : signed ? t("ui.registered") : t("ui.registerButton")}
             >
-              {signed ? "已报名" : "报名比赛"}
+              {signed ? t("ui.registered") : t("ui.registerButton")}
             </Button>
             <Button
               onClick={() => {
@@ -371,9 +404,9 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
               variant={showSubmitPanel ? "secondary" : "primary"}
               size="sm"
               className="h-[28px] text-[12px]"
-              title="提交代码"
+              title={t("ui.submit")}
             >
-              提交代码
+              {t("ui.submit")}
             </Button>
             <Button
               onClick={() => {
@@ -387,9 +420,9 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
               variant={showSubmissionHistory ? "secondary" : "primary"}
               size="sm"
               className="h-[28px] text-[12px]"
-              title="提交记录"
+              title={t("ui.submitHistoryTitle")}
             >
-              提交记录
+              {t("ui.submitHistoryTitle")}
             </Button>
           </div>
           {Rated && (
@@ -400,7 +433,7 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
                 onChange={(e) => setIsRated(e.target.checked)}
                 className="w-3 h-3"
               />
-              评级报名
+              {t("ui.ratedRegistration")}
             </label>
           )}
           {registrationMessage && (
@@ -415,25 +448,25 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
           <div className="border-b border-[var(--vscode-panel-border)] bg-[var(--vscode-textBlockQuote-background)]">
             <div className="p-3 space-y-3">
               <div className="flex items-center justify-between">
-                <div className="text-[12px] font-semibold">提交代码到 {contest}</div>
+                <div className="text-[12px] font-semibold">{t("ui.submitTo", { contest })}</div>
                 <Button
                   size="sm"
                   variant="secondary"
                   onClick={() => { setShowSubmitPanel(false); setSubmitResult(null); }}
                   className="h-[24px] text-[11px]"
                 >
-                  关闭
+                  {t("ui.close")}
                 </Button>
               </div>
 
               {submitTasks.length === 0 ? (
                 <Button onClick={handleFetchSubmitPage} disabled={isLoading} size="sm" className="h-[28px] text-[12px]">
-                  {isLoading ? "获取中..." : "获取提交页面"}
+                  {isLoading ? t("ui.fetching") : t("ui.fetchSubmitPage")}
                 </Button>
               ) : (
                 <div className="space-y-3">
                   <div className="space-y-1">
-                    <div className="text-[11px] font-semibold">题目</div>
+                    <div className="text-[11px] font-semibold">{t("ui.task")}</div>
                     <select
                       value={selectedSubmitTask}
                       onChange={(e) => setSelectedSubmitTask(e.target.value)}
@@ -446,7 +479,7 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
                   </div>
 
                   <div className="space-y-1">
-                    <div className="text-[11px] font-semibold">语言</div>
+                    <div className="text-[11px] font-semibold">{t("ui.language")}</div>
                     <select
                       value={selectedSubmitLanguage}
                       onChange={(e) => setSelectedSubmitLanguage(e.target.value)}
@@ -459,11 +492,11 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
                   </div>
 
                   <div className="space-y-1">
-                    <div className="text-[11px] font-semibold">源代码</div>
+                    <div className="text-[11px] font-semibold">{t("ui.sourceCode")}</div>
                     <textarea
                       value={sourceCode}
                       onChange={(e) => setSourceCode(e.target.value)}
-                      placeholder="在此粘贴或输入代码..."
+                      placeholder={t("ui.codePlaceholder")}
                       rows={8}
                       className="w-full text-[12px] p-2 rounded border border-[var(--vscode-input-border,#6e7681)] bg-[var(--vscode-input-background)] text-[var(--vscode-input-foreground)] outline-none focus:border-[var(--vscode-focusBorder)] resize-vertical font-mono"
                     />
@@ -476,7 +509,7 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
                       size="sm"
                       className="h-[28px] text-[12px]"
                     >
-                      {isLoading ? "提交中..." : "提交"}
+                      {isLoading ? t("ui.submitting") : t("ui.submit")}
                     </Button>
                     <Button
                       onClick={handleFetchSubmitPage}
@@ -485,13 +518,13 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
                       variant="secondary"
                       className="h-[28px] text-[12px]"
                     >
-                      刷新
+                      {t("ui.refresh")}
                     </Button>
                   </div>
 
                   {submitResult && (
                     <div className={`text-[12px] p-2 rounded ${submitResult.success ? "bg-green-500/10 text-green-500" : "bg-red-500/10 text-red-500"}`}>
-                      <div className="font-semibold mb-1">{submitResult.success ? "提交成功" : "提交失败"}</div>
+                      <div className="font-semibold mb-1">{submitResult.success ? t("ui.submitSuccessTitle") : t("ui.submitFailedTitle")}</div>
                       <div>{submitResult.message}</div>
                       {submitResult.url && (
                         <div className="mt-1">
@@ -500,7 +533,7 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
                             onClick={(e) => { e.preventDefault(); vscode.postMessage({ command: "openBrowser", url: submitResult.url }); }}
                             className="underline"
                           >
-                            查看提交记录
+                            {t("ui.viewSubmissionHistory")}
                           </a>
                         </div>
                       )}
@@ -516,7 +549,7 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
           <div className="border-b border-[var(--vscode-panel-border)] bg-[var(--vscode-textBlockQuote-background)]">
             <div className="p-3 space-y-3">
               <div className="flex items-center justify-between">
-                <div className="text-[12px] font-semibold">{contest} 提交记录</div>
+                <div className="text-[12px] font-semibold">{contest} {t("ui.submitHistoryTitle")}</div>
                 <div className="flex gap-2">
                   <Button
                     size="sm"
@@ -524,7 +557,7 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
                     disabled={loadingHistory}
                     className="h-[24px] text-[11px]"
                   >
-                    {loadingHistory ? "刷新中..." : "刷新"}
+                    {loadingHistory ? t("ui.refreshing") : t("ui.refresh")}
                   </Button>
                   <Button
                     size="sm"
@@ -532,14 +565,14 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
                     onClick={() => { setShowSubmissionHistory(false); }}
                     className="h-[24px] text-[11px]"
                   >
-                    关闭
+                    {t("ui.close")}
                   </Button>
                 </div>
               </div>
 
               {submissionHistory.length === 0 ? (
                 <div className="text-[12px] opacity-60">
-                  {loadingHistory ? "正在获取提交记录..." : "暂无提交记录"}
+                  {loadingHistory ? t("ui.loadingHistory") : t("ui.noHistory")}
                 </div>
               ) : (
                 <div className="space-y-1 max-h-[300px] overflow-y-auto">
@@ -562,7 +595,7 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
                         onClick={(e) => { e.preventDefault(); vscode.postMessage({ command: "openBrowser", url: `https://atcoder.jp/contests/${contest}/submissions/${s.id}` }); }}
                         className="text-[11px] underline opacity-60 hover:opacity-100 flex-shrink-0"
                       >
-                        查看
+                        {t("ui.view")}
                       </a>
                     </div>
                   ))}
@@ -575,7 +608,7 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
         <div className="flex-1 overflow-y-auto p-3 space-y-3">
           {tasks.length > 0 && (
             <Card className="p-3 space-y-2">
-              <div className="text-[13px] font-semibold">题目列表</div>
+              <div className="text-[13px] font-semibold">{t("ui.taskList")}</div>
               <div className="flex flex-wrap gap-2">
                 {tasks.map((task) => (
                   <Button
@@ -616,62 +649,62 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
                 </div>
                 <div className="flex flex-wrap gap-2 items-center">
                   <Button onClick={doTranslate} disabled={translating} size="sm" className="h-[26px] text-[11px]">
-                    {translating ? "翻译中..." : "翻译"}
+                    {translating ? t("ui.translating") : t("ui.translate")}
                   </Button>
                   <select
                     value={translationMode}
                     onChange={(e) => setTranslationMode(e.target.value as "api" | "free")}
                     className="h-[26px] text-[11px] px-1 rounded border border-[var(--vscode-input-border,#6e7681)] bg-[var(--vscode-input-background)] text-[var(--vscode-input-foreground)] outline-none"
-                    title="翻译模式"
+                    title={t("ui.translationMode")}
                   >
-                    <option value="free">免费</option>
-                    <option value="api">API</option>
+                    <option value="free">{t("ui.free")}</option>
+                    <option value="api">{t("ui.api")}</option>
                   </select>
                   <Button onClick={doCopyMarkdown} size="sm" variant="secondary" className="h-[26px] text-[11px]">
-                    复制 Markdown
+                    {t("ui.copyMarkdown")}
                   </Button>
-                  <Button onClick={doExportToCph} size="sm" variant="secondary" className="h-[26px] text-[11px]" title="导出到 CPH（需已安装 Competitive Programming Helper）">
-                    导出 CPH
+                  <Button onClick={doExportToCph} size="sm" variant="secondary" className="h-[26px] text-[11px]" title={t("ui.exportCphTitle")}>
+                    {t("ui.exportCph")}
                   </Button>
                 </div>
               </div>
 
               {problem.statement && (
                 <div className="space-y-1">
-                  <div className="text-[12px] font-semibold">题面</div>
+                  <div className="text-[12px] font-semibold">{t("ui.statement")}</div>
                   <HtmlContent html={problem.statement} />
-                  {translated?.["题目描述"] && (
-                    <TranslatedBlock original={problem.statement} translation={translated["题目描述"]} />
+                  {translated?.[t("text.problemStatement")] && (
+                    <TranslatedBlock original={problem.statement} translation={translated[t("text.problemStatement")]} />
                   )}
                 </div>
               )}
 
               {problem.constraints && (
                 <div className="space-y-1">
-                  <div className="text-[12px] font-semibold">约束</div>
+                  <div className="text-[12px] font-semibold">{t("text.constraints")}</div>
                   <HtmlContent html={problem.constraints} />
-                  {translated?.["约束"] && (
-                    <TranslatedBlock original={problem.constraints} translation={translated["约束"]} />
+                  {translated?.[t("text.constraints")] && (
+                    <TranslatedBlock original={problem.constraints} translation={translated[t("text.constraints")]} />
                   )}
                 </div>
               )}
 
               {problem.inputFormat && (
                 <div className="space-y-1">
-                  <div className="text-[12px] font-semibold">输入格式</div>
+                  <div className="text-[12px] font-semibold">{t("text.inputFormat")}</div>
                   <HtmlContent html={problem.inputFormat} />
-                  {translated?.["输入格式"] && (
-                    <TranslatedBlock original={problem.inputFormat} translation={translated["输入格式"]} />
+                  {translated?.[t("text.inputFormat")] && (
+                    <TranslatedBlock original={problem.inputFormat} translation={translated[t("text.inputFormat")]} />
                   )}
                 </div>
               )}
 
               {problem.outputFormat && (
                 <div className="space-y-1">
-                  <div className="text-[12px] font-semibold">输出格式</div>
+                  <div className="text-[12px] font-semibold">{t("text.outputFormat")}</div>
                   <HtmlContent html={problem.outputFormat} />
-                  {translated?.["输出格式"] && (
-                    <TranslatedBlock original={problem.outputFormat} translation={translated["输出格式"]} />
+                  {translated?.[t("text.outputFormat")] && (
+                    <TranslatedBlock original={problem.outputFormat} translation={translated[t("text.outputFormat")]} />
                   )}
                 </div>
               )}
@@ -679,14 +712,14 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
               {problem.samples?.length > 0 ? (
                 problem.samples.map((sample: SampleCase) => (
                   <div key={sample.index} className="space-y-2">
-                    <div className="text-[12px] font-semibold">Sample {sample.index}</div>
+                    <div className="text-[12px] font-semibold">{t("ui.sampleLabel", { index: sample.index })}</div>
                     <div className="rounded bg-[var(--vscode-input-background)] p-2 relative group">
                       <div className="text-[11px] opacity-60 mb-1">Input</div>
                       <pre className="text-[12px] whitespace-pre-wrap break-words">{sample.input}</pre>
                       <button
                         onClick={() => copySampleText(`${sample.index}-in`, sample.input)}
                         className="absolute top-1 right-1 opacity-0 group-hover:opacity-100 transition-opacity duration-200 w-5 h-5 flex items-center justify-center rounded hover:bg-[var(--vscode-toolbar-hoverBackground)]"
-                        title="复制 Input"
+                        title={t("ui.copyInput")}
                       >
                         {copiedSample[`${sample.index}-in`] ? (
                           <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="var(--vscode-editor-foreground)" strokeWidth="3" strokeLinecap="round" strokeLinejoin="round"><polyline points="20 6 9 17 4 12"/></svg>
@@ -701,7 +734,7 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
                       <button
                         onClick={() => copySampleText(`${sample.index}-out`, sample.output)}
                         className="absolute top-1 right-1 opacity-0 group-hover:opacity-100 transition-opacity duration-200 w-5 h-5 flex items-center justify-center rounded hover:bg-[var(--vscode-toolbar-hoverBackground)]"
-                        title="复制 Output"
+                        title={t("ui.copyOutput")}
                       >
                         {copiedSample[`${sample.index}-out`] ? (
                           <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="var(--vscode-editor-foreground)" strokeWidth="3" strokeLinecap="round" strokeLinejoin="round"><polyline points="20 6 9 17 4 12"/></svg>
@@ -714,40 +747,40 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
                 ))
               ) : problem.sampleUrl ? (
                 <div className="flex flex-col items-start gap-2">
-                  <div className="text-[12px] opacity-60">该题目没有内嵌样例，样例在外部链接中。</div>
+                  <div className="text-[12px] opacity-60">{t("ui.sampleExternal")}</div>
                   <Button
                     onClick={() => vscode.postMessage({ command: "openBrowser", url: problem.sampleUrl! })}
                     size="sm"
                     className="h-[26px] text-[11px]"
                   >
-                    查看样例
+                    {t("ui.viewSamples")}
                   </Button>
                 </div>
               ) : (
-                <div className="text-[12px] opacity-60">当前题目没有找到样例。</div>
+                <div className="text-[12px] opacity-60">{t("ui.noSamples")}</div>
               )}
             </Card>
           )}
 
           {!isLoading && tasks.length === 0 && !problem && !cfUrl && (
             <div className="flex flex-col items-center justify-center h-full text-[12px] opacity-60">
-              请输入比赛代号，例如 abc345，然后点击加载题目。
+              {t("ui.enterContestHint")}
             </div>
           )}
 
           {cfUrl && (
             <div className="p-6 flex flex-col items-center justify-center gap-4">
-              <div className="text-[14px] font-medium text-yellow-600">Cloudflare 验证</div>
+              <div className="text-[14px] font-medium text-yellow-600">{t("ui.cfTitle")}</div>
               <div className="text-[12px] opacity-70 text-center max-w-md">
-                <p className="mb-2">AtCoder 触发了 Cloudflare 验证，插件无法直接访问 AtCoder。</p>
-                <p>请直接在浏览器中打开 AtCoder 使用。</p>
+                <p className="mb-2">{t("ui.cfBody1")}</p>
+                <p>{t("ui.cfBody2")}</p>
               </div>
               <div className="flex gap-3 mt-2 flex-wrap justify-center">
                 <Button onClick={() => vscode.postMessage({ command: "openBrowser", url: cfUrl })} className="h-[32px] text-[12px]">
-                  在浏览器中打开
+                  {t("ui.openInBrowser")}
                 </Button>
                 <Button onClick={() => { setCfUrl(null); }} className="h-[32px] text-[12px]">
-                  关闭
+                  {t("ui.close")}
                 </Button>
               </div>
             </div>
@@ -756,7 +789,7 @@ const WebviewApp: React.FC<WebviewAppProps> = ({
           {isLoading && (
             <div className="flex items-center gap-2 text-[12px] opacity-70">
               <Spinner size="sm" />
-              <span>正在抓取数据...</span>
+              <span>{t("ui.fetchingData")}</span>
             </div>
           )}
         </div>
diff --git a/packages/webview/src/i18n/en.ts b/packages/webview/src/i18n/en.ts
new file mode 100644
index 0000000..2f365ab
--- /dev/null
+++ b/packages/webview/src/i18n/en.ts
@@ -0,0 +1,157 @@
+import type { zh } from "./zh";
+
+export type ZhDict = typeof zh;
+
+export const en: Record<keyof ZhDict, string> = {
+    "status.tasksLoaded": "Loaded {count} problems",
+    "status.problemLoaded": "Statement loaded: {title}",
+    "status.loading": "Loading...",
+    "err.operationFailed": "Operation failed",
+    "err.detail": "Failed to fetch submission details",
+    "err.submitPageUnavailable": "Submit page unavailable",
+    "status.translationDone": "Translation complete",
+    "status.registrationSuccess": "Registered",
+    "status.registrationFail": "Registration failed",
+    "status.submitPageReady": "Submit page loaded",
+    "status.submitSuccess": "Code submitted successfully",
+    "status.submitFailed": "Submission failed",
+    "status.historyLoaded": "Loaded {count} submissions",
+    "status.loadingContest": "Loading problems for {contest}...",
+    "status.fetchingProblem": "Fetching statement for {contest}/{task}...",
+    "status.registration": "Registering for {contest} ...",
+    "status.copying": "Copying...",
+    "status.translating": "Translating...",
+    "status.exportingCph": "Exporting to CPH...",
+    "status.fetchingSubmitPage": "Fetching submit page...",
+    "status.fetchingHistory": "Fetching submission history...",
+    "status.submitting": "Submitting code...",
+    "status.sentToCph": "Sent to CPH",
+    "status.cphExportFailed": "Failed to export to CPH",
+    "status.cfChallenge": "AtCoder triggered Cloudflare verification that cannot be bypassed. Please use your browser",
+    "status.loginRequired": "You need to sign in to AtCoder. Please sign in in your browser, then paste the Cookie into settings",
+    "status.standingsLoaded": "Loaded {count} standings entries",
+    "status.fetchingStandings": "Fetching standings for {contest}...",
+    "status.homepageLoaded": "Loaded {count} contests",
+    "status.fetchingHomepage": "Fetching AtCoder homepage contest list...",
+    "status.detailLoaded": "Loaded submission {id}",
+    "status.cfOpenBrowser": "AtCoder triggered Cloudflare verification, please open it in your browser",
+    "status.loginRequiredSidebar": "You need to sign in to AtCoder. Please set the Cookie in the sidebar and try again",
+
+    "text.problemStatement": "Problem Statement",
+    "text.constraints": "Constraints",
+    "text.inputFormat": "Input Format",
+    "text.outputFormat": "Output Format",
+
+    "ui.settings": "Settings",
+    "ui.save": "Save",
+    "ui.clear": "Clear",
+    "ui.close": "Close",
+    "ui.refresh": "Refresh",
+    "ui.refreshing": "Refreshing...",
+    "ui.view": "View",
+    "ui.details": "Details",
+    "ui.task": "Task",
+    "ui.language": "Language",
+    "ui.sourceCode": "Source code",
+    "ui.submit": "Submit",
+    "ui.submitting": "Submitting...",
+    "ui.fetching": "Fetching...",
+    "ui.openInBrowser": "Open in Browser",
+    "ui.browserOpen": "Open in browser",
+    "ui.fetchingData": "Fetching data...",
+    "ui.cfTitle": "Cloudflare Verification",
+    "ui.cfBody1": "AtCoder triggered Cloudflare verification, so the extension cannot access AtCoder directly.",
+    "ui.cfBody2": "Please open AtCoder in your browser.",
+    "ui.cfContestBody": "AtCoder triggered Cloudflare verification, so the extension cannot access it directly. Please click the button below to open it in your browser, complete verification, then set the Cookie again.",
+    "ui.registerButton": "Register",
+    "ui.registered": "Registered",
+    "ui.setCookieFirst": "Please set your AtCoder Cookie first",
+    "ui.ratedRegistration": "Rated registration",
+    "ui.announcement": "Announcement",
+    "ui.contest": "Contest {contest}",
+    "ui.contestId": "Contest ID: {contest}",
+    "ui.isRated": "Rated contest: {rated}",
+    "ui.yes": "Yes",
+    "ui.no": "No",
+    "ui.noTasks": "No problems for {contest}",
+    "ui.noHistory": "No submissions yet",
+    "ui.loadingHistory": "Fetching submission history...",
+    "ui.noStandings": "No standings data",
+    "ui.noContests": "No contests, click refresh",
+    "ui.fetchingContests": "Fetching contest list...",
+    "ui.contestsTitle": "Contests",
+    "ui.submitHistoryTitle": "Submissions",
+    "ui.clickContestForHistory": "Click a contest to view submissions",
+    "ui.submitTo": "Submit code to {contest}",
+    "ui.clickToStart": "Click \"Fetch submit page\" to start.",
+    "ui.submitSuccessTitle": "Submitted",
+    "ui.submitFailedTitle": "Submission failed",
+    "ui.viewSubmissionHistory": "View submission history",
+    "ui.taskList": "Problem list",
+    "ui.statement": "Statement",
+    "ui.translate": "Translate",
+    "ui.translating": "Translating...",
+    "ui.translationMode": "Translation mode",
+    "ui.free": "Free",
+    "ui.api": "API",
+    "ui.copyMarkdown": "Copy Markdown",
+    "ui.exportCph": "Export CPH",
+    "ui.exportCphTitle": "Export to CPH (requires Competitive Programming Helper)",
+    "ui.sampleLabel": "Sample {index}",
+    "ui.copyInput": "Copy Input",
+    "ui.copyOutput": "Copy Output",
+    "ui.sampleExternal": "This problem has no embedded samples; samples are in an external link.",
+    "ui.viewSamples": "View samples",
+    "ui.noSamples": "No samples found for this problem.",
+    "ui.enterContestHint": "Enter a contest ID, e.g. abc345, then click Load problems.",
+    "ui.standingsTitle": "Standings - {contest}",
+    "ui.tabInfo": "Info",
+    "ui.tabRating": "Standings",
+    "ui.fetchingStandings": "Fetching standings...",
+    "ui.openSubmitPage": "Open submit page in browser",
+    "ui.codePlaceholder": "Paste or type code here...",
+    "ui.contestPlaceholder": "Enter contest code, e.g. abc345",
+    "ui.loadTasks": "Load problems",
+    "ui.submissionTitle": "Submission {id} - {contest}",
+    "ui.missingContestOrId": "Missing contest ID or submission ID",
+    "ui.fetchingDetail": "Fetching submission details...",
+    "ui.noDetail": "No submission details",
+    "ui.submitTime": "Submission time",
+    "ui.score": "Score",
+    "ui.codeLength": "Code length",
+    "ui.execTime": "Exec time",
+    "ui.memory": "Memory",
+    "ui.testPoints": "Test cases",
+    "ui.collapse": "Collapse",
+    "ui.expand": "Expand",
+    "ui.copied": "Copied",
+    "ui.copy": "Copy",
+
+    "cat.active": "Active",
+    "cat.upcoming": "Upcoming",
+    "cat.recent": "Recent",
+    "cat.daily": "Daily",
+
+    "cookie.title": "AtCoder login Cookie",
+    "cookie.onlyNeedRevel": "AtCoder only needs a single {code} Cookie to sign in.",
+    "cookie.steps": "Steps:",
+    "cookie.step1": "Open {link} in your browser and sign in",
+    "cookie.step2": "Press {key} to open DevTools",
+    "cookie.step3": "Go to the {application} (Chrome) or {storage} (Edge) tab",
+    "cookie.step4": "On the left, find {cookies} → {site}",
+    "cookie.step5": "Find the row named {code}, double-click the {value} column to select and copy",
+    "cookie.step6": "Paste it into the input below (no need to add the prefix manually)",
+    "cookie.chromeApp": "Application",
+    "cookie.edgeStorage": "Storage",
+    "cookie.placeholderHas": "Cookie saved; enter a new value to overwrite",
+    "cookie.placeholderEmpty": "Paste the REVEL_SESSION value",
+    "cookie.pasteFirst": "Please copy the REVEL_SESSION value first",
+    "cookie.saved": "Cookie saved",
+    "cookie.cleared": "Cookie cleared",
+    "cookie.updated": "Cookie updated, refreshing...",
+    "cookie.clearLabel": "Clear Cookie",
+    "cookie.loginTitle": "Sign in to AtCoder",
+    "cookie.loginDesc": "Submissions and standings require login. Sign in to AtCoder in your browser, press F12 → Application → Cookies, copy the {code} value, and paste it below.",
+    "cookie.loginRequired": "Sign in to AtCoder to use this feature",
+    "cookie.loggedIn": "Signed in to AtCoder",
+};
diff --git a/packages/webview/src/i18n/index.tsx b/packages/webview/src/i18n/index.tsx
new file mode 100644
index 0000000..4bf46e2
--- /dev/null
+++ b/packages/webview/src/i18n/index.tsx
@@ -0,0 +1,62 @@
+import React, { createContext, useContext, useMemo, useState } from "react";
+import { zh } from "./zh";
+import { en } from "./en";
+import type { ZhDict } from "./zh";
+
+type Dict = Record<string, string>;
+
+const dicts: Record<string, Dict> = { zh, en };
+const fallback: Dict = en;
+
+function detectLocale(): string {
+    const lang = (window.__ATCODER_LOCALE__ || navigator.language || "en").toLowerCase();
+    return lang.startsWith("zh") ? "zh" : "en";
+}
+
+export interface I18nValue {
+    locale: string;
+    t: (key: string, params?: Record<string, string | number>) => string;
+    nodes: (template: string, nodeMap: Record<string, React.ReactNode>) => React.ReactNode[];
+}
+
+const I18nContext = createContext<I18nValue>({
+    locale: "en",
+    t: (key: string) => key,
+    nodes: (template: string) => [template],
+});
+
+export const I18nProvider: React.FC<{ children: React.ReactNode }> = ({ children }) => {
+    const [locale] = useState<string>(detectLocale());
+
+    const value = useMemo<I18nValue>(() => {
+        const dict = dicts[locale] ?? fallback;
+        const t = (key: string, params?: Record<string, string | number>): string => {
+            let text = dict[key] ?? fallback[key] ?? key;
+            if (params) {
+                for (const [k, v] of Object.entries(params)) {
+                    text = text.replace(new RegExp(`\\{${k}\\}`, "g"), String(v));
+                }
+            }
+            return text;
+        };
+        const nodes = (template: string, nodeMap: Record<string, React.ReactNode>): React.ReactNode[] => {
+            const parts: React.ReactNode[] = [];
+            const regex = /\{(\w+)\}/g;
+            let last = 0;
+            let m: RegExpExecArray | null;
+            let i = 0;
+            while ((m = regex.exec(template)) !== null) {
+                if (m.index > last) parts.push(template.slice(last, m.index));
+                parts.push(<React.Fragment key={i++}>{nodeMap[m[1]] ?? m[0]}</React.Fragment>);
+                last = regex.lastIndex;
+            }
+            if (last < template.length) parts.push(template.slice(last));
+            return parts;
+        };
+        return { locale, t, nodes };
+    }, [locale]);
+
+    return <I18nContext.Provider value={value}>{children}</I18nContext.Provider>;
+};
+
+export const useI18n = (): I18nValue => useContext(I18nContext);
diff --git a/packages/webview/src/i18n/zh.ts b/packages/webview/src/i18n/zh.ts
new file mode 100644
index 0000000..db5431e
--- /dev/null
+++ b/packages/webview/src/i18n/zh.ts
@@ -0,0 +1,152 @@
+export const zh = {
+    "status.tasksLoaded": "已加载 {count} 道题目",
+    "status.problemLoaded": "已加载题面：{title}",
+    "status.loading": "加载中...",
+    "err.operationFailed": "操作失败",
+    "err.detail": "获取提交详情失败",
+    "err.submitPageUnavailable": "提交页面无法访问",    "status.translationDone": "翻译完成",
+    "status.registrationSuccess": "报名成功",
+    "status.registrationFail": "报名失败",
+    "status.submitPageReady": "已获取提交页面信息",
+    "status.submitSuccess": "代码提交成功",
+    "status.submitFailed": "提交失败",
+    "status.historyLoaded": "已获取 {count} 条提交记录",
+    "status.loadingContest": "正在加载 {contest} 的题目...",
+    "status.fetchingProblem": "正在抓取 {contest}/{task} 的题面...",
+    "status.registration": "正在报名 {contest} ...",
+    "status.copying": "正在复制...",
+    "status.translating": "正在翻译...",
+    "status.exportingCph": "正在导出到 CPH...",
+    "status.fetchingSubmitPage": "正在获取提交页面...",
+    "status.fetchingHistory": "正在获取提交记录...",
+    "status.submitting": "正在提交代码...",
+    "status.sentToCph": "已发送到 CPH",
+    "status.cphExportFailed": "导出到 CPH 失败",
+    "status.cfChallenge": "AtCoder 触发 Cloudflare 验证，插件无法直接访问，请在浏览器中使用",
+    "status.loginRequired": "需要登录 AtCoder 才能查看。请在浏览器中登录，然后将 Cookie 粘贴到设置中",
+    "status.standingsLoaded": "已获取 {count} 条排行",
+    "status.fetchingStandings": "正在获取 {contest} 排行榜...",
+    "status.homepageLoaded": "已获取 {count} 场比赛",
+    "status.fetchingHomepage": "正在抓取 AtCoder 首页比赛列表...",
+    "status.detailLoaded": "已加载提交 {id}",
+    "status.cfOpenBrowser": "AtCoder 触发 Cloudflare 验证，请在浏览器中打开查看",
+    "status.loginRequiredSidebar": "需要登录 AtCoder 账号，请在侧边栏设置 Cookie 后再试",
+
+    "text.problemStatement": "题目描述",
+    "text.constraints": "约束",
+    "text.inputFormat": "输入格式",
+    "text.outputFormat": "输出格式",
+
+    "ui.settings": "设置",
+    "ui.save": "保存",
+    "ui.clear": "清除",
+    "ui.close": "关闭",
+    "ui.refresh": "刷新",
+    "ui.refreshing": "刷新中...",
+    "ui.view": "查看",
+    "ui.details": "详情",
+    "ui.task": "题目",
+    "ui.language": "语言",
+    "ui.sourceCode": "源代码",
+    "ui.submit": "提交",
+    "ui.submitting": "提交中...",
+    "ui.fetching": "获取中...",
+    "ui.openInBrowser": "在浏览器中打开",
+    "ui.browserOpen": "浏览器打开",
+    "ui.fetchingData": "正在抓取数据...",
+    "ui.cfTitle": "Cloudflare 验证",
+    "ui.cfBody1": "AtCoder 触发了 Cloudflare 验证，插件无法直接访问 AtCoder。",
+    "ui.cfBody2": "请直接在浏览器中打开 AtCoder 使用。",
+    "ui.cfContestBody": "AtCoder 触发了 Cloudflare 验证，插件无法直接访问。请点击下方按钮在浏览器中打开，完成验证后重新设置 Cookie 再试。",
+    "ui.registerButton": "报名比赛",
+    "ui.registered": "已报名",
+    "ui.setCookieFirst": "请先设置 AtCoder Cookie",
+    "ui.ratedRegistration": "评级报名",
+    "ui.announcement": "公告",
+    "ui.contest": "比赛 {contest}",
+    "ui.contestId": "比赛代号：{contest}",
+    "ui.isRated": "评级比赛：{rated}",
+    "ui.yes": "是",
+    "ui.no": "否",
+    "ui.noTasks": "暂无 {contest} 的题目",
+    "ui.noHistory": "暂无提交记录",
+    "ui.loadingHistory": "正在获取提交记录...",
+    "ui.noStandings": "暂无排行数据",
+    "ui.noContests": "暂无比赛，点击刷新",
+    "ui.fetchingContests": "正在抓取比赛列表...",
+    "ui.contestsTitle": "比赛列表",
+    "ui.submitHistoryTitle": "提交记录",
+    "ui.clickContestForHistory": "点击比赛查看提交记录",
+    "ui.submitTo": "提交代码到 {contest}",
+    "ui.clickToStart": "点击「获取提交页面」开始提交。",
+    "ui.submitSuccessTitle": "提交成功",
+    "ui.submitFailedTitle": "提交失败",
+    "ui.viewSubmissionHistory": "查看提交记录",
+    "ui.taskList": "题目列表",
+    "ui.statement": "题面",
+    "ui.translate": "翻译",
+    "ui.translating": "翻译中...",
+    "ui.translationMode": "翻译模式",
+    "ui.free": "免费",
+    "ui.api": "API",
+    "ui.copyMarkdown": "复制 Markdown",
+    "ui.exportCph": "导出 CPH",
+    "ui.exportCphTitle": "导出到 CPH（需已安装 Competitive Programming Helper）",
+    "ui.sampleLabel": "Sample {index}",
+    "ui.copyInput": "复制 Input",
+    "ui.copyOutput": "复制 Output",
+    "ui.sampleExternal": "该题目没有内嵌样例，样例在外部链接中。",
+    "ui.viewSamples": "查看样例",
+    "ui.noSamples": "当前题目没有找到样例。",
+    "ui.enterContestHint": "请输入比赛代号，例如 abc345，然后点击加载题目。",
+    "ui.standingsTitle": "排行榜 - {contest}",
+    "ui.tabInfo": "信息",
+    "ui.tabRating": "排行",
+    "ui.fetchingStandings": "正在获取排行榜...",
+    "ui.openSubmitPage": "在浏览器中打开提交页",
+    "ui.codePlaceholder": "在此粘贴或输入代码...",
+    "ui.contestPlaceholder": "输入比赛代码，如 abc345",
+    "ui.loadTasks": "加载题目",
+    "ui.submissionTitle": "提交 {id} - {contest}",
+    "ui.missingContestOrId": "缺少比赛代号或提交 ID",
+    "ui.fetchingDetail": "正在获取提交详情...",
+    "ui.noDetail": "无提交详情",
+    "ui.submitTime": "提交时间",
+    "ui.score": "得分",
+    "ui.codeLength": "代码长度",
+    "ui.execTime": "执行时间",
+    "ui.memory": "内存",
+    "ui.testPoints": "测试点",
+    "ui.collapse": "收起",
+    "ui.expand": "展开",
+    "ui.copied": "已复制",
+    "ui.copy": "复制",
+
+    "cat.active": "进行中",
+    "cat.upcoming": "即将开始",
+    "cat.recent": "最近",
+    "cat.daily": "每日",
+
+    "cookie.title": "AtCoder 登录 Cookie",
+    "cookie.onlyNeedRevel": "AtCoder 仅需 {code} 一个 Cookie 即可登录。",
+    "cookie.steps": "获取步骤：",
+    "cookie.step1": "在浏览器中打开 {link} 并登录",
+    "cookie.step2": "按 {key} 打开开发者工具",
+    "cookie.step3": "切换到 {application}（Chrome）或 {storage}（Edge）标签页",
+    "cookie.step4": "左侧找到 {cookies} → {site}",
+    "cookie.step5": "找到名为 {code} 的行，双击 {value} 列全选复制",
+    "cookie.step6": "粘贴到下方输入框（无需手动加前缀，插件会自动补全）",
+    "cookie.chromeApp": "Application",
+    "cookie.edgeStorage": "存储",
+    "cookie.placeholderHas": "已保存 Cookie，输入新值可覆盖",
+    "cookie.placeholderEmpty": "粘贴 REVEL_SESSION 的 Value",
+    "cookie.pasteFirst": "请先复制 REVEL_SESSION 的值再保存",
+    "cookie.saved": "Cookie 已保存",
+    "cookie.cleared": "Cookie 已清除",
+    "cookie.updated": "Cookie 已更新，正在刷新...",
+    "cookie.clearLabel": "清除 Cookie",
+    "cookie.loginTitle": "需要登录 AtCoder 账号",
+    "cookie.loginDesc": "提交记录、排行榜等需要登录。请在浏览器登录 AtCoder，按 F12 → Application → Cookies 复制 {code} 的 Value 粘贴到下方。",
+    "cookie.loginRequired": "需要登录 AtCoder 账号才能使用该功能",
+    "cookie.loggedIn": "已登录 AtCoder",
+};
diff --git a/packages/webview/src/index.tsx b/packages/webview/src/index.tsx
index 342f8c6..a12d8f3 100644
--- a/packages/webview/src/index.tsx
+++ b/packages/webview/src/index.tsx
@@ -1,6 +1,7 @@
 import React from "react";
 import { createRoot } from "react-dom/client";
 import { VSCodeProvider } from "./VSCodeProvider";
+import { I18nProvider } from "./i18n";
 import { WebviewApp } from "./WebviewApp";
 import { SidebarApp } from "./SidebarApp";
 import { ContestApp } from "./ContestApp";
@@ -14,20 +15,22 @@ if (container) {
   const root = createRoot(container);
   root.render(
     <React.StrictMode>
-      <VSCodeProvider>
-        {mode === "contest" ? (
-          <ContestApp initContest={window.__ATCODER_INIT_CONTEST__} />
-        ) : mode === "sidebar" ? (
-          <SidebarApp />
-        ) : mode === "submission" ? (
-          <SubmissionDetailApp
-            initContest={window.__ATCODER_INIT_CONTEST__}
-            initSubmissionId={window.__ATCODER_SUBMISSION_ID__}
-          />
-        ) : (
-          <WebviewApp />
-        )}
-      </VSCodeProvider>
+      <I18nProvider>
+        <VSCodeProvider>
+          {mode === "contest" ? (
+            <ContestApp initContest={window.__ATCODER_INIT_CONTEST__} />
+          ) : mode === "sidebar" ? (
+            <SidebarApp />
+          ) : mode === "submission" ? (
+            <SubmissionDetailApp
+              initContest={window.__ATCODER_INIT_CONTEST__}
+              initSubmissionId={window.__ATCODER_SUBMISSION_ID__}
+            />
+          ) : (
+            <WebviewApp />
+          )}
+        </VSCodeProvider>
+      </I18nProvider>
     </React.StrictMode>
   );
 }
diff --git a/packages/webview/src/types.ts b/packages/webview/src/types.ts
index 8194dd6..2e81368 100644
--- a/packages/webview/src/types.ts
+++ b/packages/webview/src/types.ts
@@ -126,6 +126,7 @@ declare global {
     __ATCODER_MODE__?: "editor" | "sidebar" | "contest" | "submission";
     __ATCODER_INIT_CONTEST__?: string;
     __ATCODER_SUBMISSION_ID__?: string;
+    __ATCODER_LOCALE__?: string;
   }
 }