feat: ship minecraft theme updates and platform workflow improvements

2026-02-15 17:36:56 +08:00
--- a/frontend/src/app/api/image-cache/route.ts
+++ b/frontend/src/app/api/image-cache/route.ts
@@ -8,6 +8,16 @@ export const runtime = "nodejs";

 const CACHE_DIR = process.env.CSP_IMAGE_CACHE_DIR ?? "/tmp/csp-image-cache";
 const MAX_BYTES = 5 * 1024 * 1024;
+const IMAGE_EXT_TO_TYPE: Record<string, string> = {
+  ".png": "image/png",
+  ".jpg": "image/jpeg",
+  ".jpeg": "image/jpeg",
+  ".webp": "image/webp",
+  ".gif": "image/gif",
+  ".svg": "image/svg+xml",
+  ".bmp": "image/bmp",
+  ".ico": "image/x-icon",
+};

 function toArrayBuffer(view: Uint8Array): ArrayBuffer {
  return view.buffer.slice(
@@ -28,6 +38,25 @@ function pickExt(urlObj: URL, contentType: string): string {
  return ".img";
 }

+function inferImageType(urlObj: URL, contentType: string): string {
+  const raw = contentType.split(";")[0].trim().toLowerCase();
+  if (raw.startsWith("image/")) return raw;
+  const ext = path.extname(urlObj.pathname || "").toLowerCase();
+  return IMAGE_EXT_TO_TYPE[ext] ?? raw;
+}
+
+function looksLikeImage(urlObj: URL, contentType: string): boolean {
+  if (contentType.startsWith("image/")) return true;
+  const ext = path.extname(urlObj.pathname || "").toLowerCase();
+  return Boolean(IMAGE_EXT_TO_TYPE[ext]);
+}
+
+function redirectToTarget(target: URL): NextResponse {
+  const res = NextResponse.redirect(target.toString(), 307);
+  res.headers.set("Cache-Control", "no-store");
+  return res;
+}
+
 async function readCachedByKey(
  key: string
 ): Promise<{ data: Uint8Array; contentType: string } | null> {
@@ -94,14 +123,12 @@ export async function GET(req: NextRequest) {
    });

    if (!resp.ok) {
-      return NextResponse.json(
-        { ok: false, error: `fetch image failed: HTTP ${resp.status}` },
-        { status: 502 }
-      );
+      return redirectToTarget(target);
    }

-    const contentType = (resp.headers.get("content-type") ?? "").toLowerCase();
-    if (!contentType.startsWith("image/")) {
+    const headerType = (resp.headers.get("content-type") ?? "").toLowerCase();
+    const contentType = inferImageType(target, headerType);
+    if (!looksLikeImage(target, contentType)) {
      return NextResponse.json({ ok: false, error: "url is not an image" }, { status: 400 });
    }

@@ -125,11 +152,8 @@ export async function GET(req: NextRequest) {
        "Cache-Control": "public, max-age=31536000, immutable",
      },
    });
-  } catch (e: unknown) {
-    return NextResponse.json(
-      { ok: false, error: `fetch image failed: ${String(e)}` },
-      { status: 502 }
-    );
+  } catch {
+    return redirectToTarget(target);
  } finally {
    clearTimeout(timer);
  }
--- a/frontend/src/app/backend-logs/page.tsx
+++ b/frontend/src/app/backend-logs/page.tsx
@@ -59,6 +59,20 @@ type TriggerMissingResp = {
  max_solutions: number;
 };

+type AdminUser = {
+  id: number;
+  username: string;
+  rating: number;
+  created_at: number;
+};
+
+type AdminUsersResp = {
+  items: AdminUser[];
+  total_count: number;
+  page: number;
+  page_size: number;
+};
+
 function fmtTs(v: number | null | undefined): string {
  if (!v) return "-";
  return new Date(v * 1000).toLocaleString();
@@ -81,17 +95,24 @@ export default function BackendLogsPage() {
  const [queuedIds, setQueuedIds] = useState<number[]>([]);
  const [triggerLoading, setTriggerLoading] = useState(false);
  const [triggerMsg, setTriggerMsg] = useState("");
+  const [users, setUsers] = useState<AdminUser[]>([]);
+  const [deleteUserId, setDeleteUserId] = useState<number | null>(null);
+  const [userMsg, setUserMsg] = useState("");

  const refresh = async () => {
    if (!isAdmin || !token) return;
    setLoading(true);
    setError("");
    try {
-      const data = await apiFetch<BackendLogsResp>(
-        `/api/v1/backend/logs?limit=${limit}&running_limit=20&queued_limit=100`,
-        {},
-        token
-      );
+      const [data, usersData] = await Promise.all([
+        apiFetch<BackendLogsResp>(
+          `/api/v1/backend/logs?limit=${limit}&running_limit=20&queued_limit=100`,
+          {},
+          token
+        ),
+        apiFetch<AdminUsersResp>("/api/v1/admin/users?page=1&page_size=200", {}, token),
+      ]);
+
      setPendingJobs(data.pending_jobs ?? 0);
      setMissingProblems(data.missing_problems ?? 0);
      setItems(data.items ?? []);
@@ -99,6 +120,7 @@ export default function BackendLogsPage() {
      setQueuedJobs(data.queued_jobs ?? []);
      setRunningIds(data.running_problem_ids ?? []);
      setQueuedIds(data.queued_problem_ids ?? []);
+      setUsers(usersData.items ?? []);
    } catch (e: unknown) {
      setError(String(e));
    } finally {
@@ -185,6 +207,45 @@ export default function BackendLogsPage() {
    }
  };

+  const deleteUser = async (user: AdminUser) => {
+    if (!isAdmin || !token) return;
+    if (user.username === "admin") {
+      setError(tx("保留管理员账号不可删除", "Reserved admin account cannot be deleted"));
+      return;
+    }
+    const ok = window.confirm(
+      tx(
+        `确认删除用户 ${user.username}(#${user.id})？该用户提交记录、错题本、草稿、积分记录会被级联删除。`,
+        `Delete user ${user.username}(#${user.id})? Submissions, wrong-book, drafts, and points records will be removed by cascade.`
+      )
+    );
+    if (!ok) return;
+
+    setDeleteUserId(user.id);
+    setError("");
+    setUserMsg("");
+    try {
+      await apiFetch(
+        `/api/v1/admin/users/${user.id}`,
+        {
+          method: "DELETE",
+        },
+        token
+      );
+      setUserMsg(
+        tx(
+          `已删除用户 ${user.username}(#${user.id})`,
+          `Deleted user ${user.username}(#${user.id}).`
+        )
+      );
+      await refresh();
+    } catch (e: unknown) {
+      setError(String(e));
+    } finally {
+      setDeleteUserId(null);
+    }
+  };
+
  useEffect(() => {
    if (!isAdmin || !token) return;
    const timer = setInterval(() => {
@@ -250,12 +311,94 @@ export default function BackendLogsPage() {

      {error && <p className="mt-3 text-sm text-red-600">{error}</p>}
      {triggerMsg && <p className="mt-3 text-sm text-emerald-700">{triggerMsg}</p>}
+      {userMsg && <p className="mt-3 text-sm text-emerald-700">{userMsg}</p>}
      <p className="mt-3 text-xs text-zinc-500">
        {tx(
          "系统已自动单线程异步处理待队列任务，无需手工点击；上方按钮仅用于立即手动补全。",
          "System auto-processes queued jobs in single-thread async mode; the button above is only for manual trigger."
        )}
      </p>
+
+      <section className="mt-4 rounded-xl border bg-white p-3">
+        <div className="flex flex-wrap items-center justify-between gap-2">
+          <h2 className="text-sm font-medium">{tx("用户管理（可删除）", "User Management (Delete Supported)")}</h2>
+          <p className="text-xs text-zinc-600">
+            {tx("总用户", "Total users")} {users.length}
+          </p>
+        </div>
+
+        <div className="mt-3 divide-y md:hidden">
+          {users.map((user) => (
+            <article key={user.id} className="space-y-1 py-2 text-xs">
+              <p className="font-medium">
+                #{user.id} · {user.username}
+              </p>
+              <p className="text-zinc-600">
+                Rating {user.rating} · {tx("创建", "Created")} {fmtTs(user.created_at)}
+              </p>
+              <button
+                className="rounded border px-2 py-1 text-xs text-red-700 hover:bg-red-50 disabled:opacity-60"
+                disabled={deleteUserId === user.id || user.username === "admin"}
+                onClick={() => void deleteUser(user)}
+              >
+                {user.username === "admin"
+                  ? tx("保留账号", "Reserved")
+                  : deleteUserId === user.id
+                    ? tx("删除中...", "Deleting...")
+                    : tx("删除用户", "Delete User")}
+              </button>
+            </article>
+          ))}
+          {!loading && users.length === 0 && (
+            <p className="py-4 text-center text-sm text-zinc-500">{tx("暂无用户数据", "No users found")}</p>
+          )}
+        </div>
+
+        <div className="mt-2 hidden overflow-x-auto md:block">
+          <table className="min-w-full text-xs">
+            <thead className="bg-zinc-100 text-left">
+              <tr>
+                <th className="px-2 py-2">ID</th>
+                <th className="px-2 py-2">{tx("用户名", "Username")}</th>
+                <th className="px-2 py-2">Rating</th>
+                <th className="px-2 py-2">{tx("创建时间", "Created At")}</th>
+                <th className="px-2 py-2">{tx("操作", "Action")}</th>
+              </tr>
+            </thead>
+            <tbody>
+              {users.map((user) => (
+                <tr key={user.id} className="border-t">
+                  <td className="px-2 py-2">{user.id}</td>
+                  <td className="px-2 py-2">{user.username}</td>
+                  <td className="px-2 py-2">{user.rating}</td>
+                  <td className="px-2 py-2 text-zinc-600">{fmtTs(user.created_at)}</td>
+                  <td className="px-2 py-2">
+                    <button
+                      className="rounded border px-2 py-1 text-xs text-red-700 hover:bg-red-50 disabled:opacity-60"
+                      disabled={deleteUserId === user.id || user.username === "admin"}
+                      onClick={() => void deleteUser(user)}
+                    >
+                      {user.username === "admin"
+                        ? tx("保留账号", "Reserved")
+                        : deleteUserId === user.id
+                          ? tx("删除中...", "Deleting...")
+                          : tx("删除用户", "Delete User")}
+                    </button>
+                  </td>
+                </tr>
+              ))}
+              {!loading && users.length === 0 && (
+                <tr>
+                  <td className="px-2 py-4 text-center text-zinc-500" colSpan={5}>
+                    {tx("暂无用户数据", "No users found")}
+                  </td>
+                </tr>
+              )}
+            </tbody>
+          </table>
+        </div>
+      </section>
+
      <section className="mt-4 grid gap-3 md:grid-cols-2">
        <article className="rounded-xl border bg-white p-3">
          <h2 className="text-sm font-medium">{tx("正在处理（Running）", "Running Jobs")}</h2>
--- a/frontend/src/app/globals.css
+++ b/frontend/src/app/globals.css
@@ -35,6 +35,11 @@ body {
  font-size: 1em;
 }

+.solution-code-block {
+  font-size: calc(0.875rem * 0.7) !important;
+  line-height: 1.05rem !important;
+}
+
 .print-only {
  display: none;
 }
--- a/frontend/src/app/me/page.tsx
+++ b/frontend/src/app/me/page.tsx
@@ -2,6 +2,7 @@

 import { useEffect, useMemo, useState } from "react";

+import { PixelAvatar } from "@/components/pixel-avatar";
 import { apiFetch } from "@/lib/api";
 import { readToken } from "@/lib/auth";
 import { useI18nText } from "@/lib/i18n";
@@ -218,10 +219,23 @@ export default function MePage() {

      {profile && (
        <section className="mt-4 rounded-xl border bg-white p-4 text-sm">
-          <p>ID: {profile.id}</p>
-          <p>{tx("用户名", "Username")}: {profile.username}</p>
-          <p>Rating: {profile.rating}</p>
-          <p>{tx("创建时间", "Created At")}: {fmtTs(profile.created_at)}</p>
+          <div className="flex flex-wrap items-center gap-4">
+            <PixelAvatar
+              seed={`${profile.username}-${profile.id}`}
+              size={72}
+              className="border-zinc-700"
+              alt={`${profile.username} avatar`}
+            />
+            <div className="space-y-1">
+              <p>ID: {profile.id}</p>
+              <p>{tx("用户名", "Username")}: {profile.username}</p>
+              <p>Rating: {profile.rating}</p>
+              <p>{tx("创建时间", "Created At")}: {fmtTs(profile.created_at)}</p>
+              <p className="text-xs text-zinc-500">
+                {tx("默认像素头像按账号随机生成，可作为主题角色形象。", "Default pixel avatar is randomly generated by account as your theme character.")}
+              </p>
+            </div>
+          </div>
        </section>
      )}

--- a/frontend/src/app/problems/[id]/page.tsx
+++ b/frontend/src/app/problems/[id]/page.tsx
@@ -2,7 +2,7 @@

 import Link from "next/link";
 import { useParams } from "next/navigation";
-import { useEffect, useMemo, useState } from "react";
+import { useEffect, useMemo, useRef, useState } from "react";

 import { CodeEditor } from "@/components/code-editor";
 import { MarkdownRenderer } from "@/components/markdown-renderer";
@@ -100,6 +100,12 @@ function scoreRatio(score: number): number {
  return Math.max(0, Math.min(100, score));
 }

+function buildDraftSignature(code: string, stdinText: string): string {
+  const normCode = normalizeCodeText(code);
+  const normStdin = (stdinText ?? "").replace(/\r\n?/g, "\n");
+  return `${normCode}\n__STDIN__\n${normStdin}`;
+}
+
 type ResultTone = {
  title: string;
  icon: string;
@@ -154,7 +160,8 @@ type DraftResp = {
  language: string;
  code: string;
  stdin: string;
-  updated_at: number;
+  updated_at: number | null;
+  exists?: boolean;
 };

 type SolutionItem = {
@@ -292,6 +299,14 @@ export default function ProblemDetailPage() {
  const [solutionData, setSolutionData] = useState<SolutionResp | null>(null);
  const [solutionMsg, setSolutionMsg] = useState("");
  const [printAnswerMarkdown, setPrintAnswerMarkdown] = useState("");
+  const draftLatestRef = useRef<{ code: string; stdin: string }>({
+    code: starterCode,
+    stdin: defaultRunInput,
+  });
+  const draftLastSavedSigRef = useRef<string>(
+    buildDraftSignature(starterCode, defaultRunInput)
+  );
+  const draftAutoSavingRef = useRef(false);

  const llmProfile = useMemo<LlmProfile | null>(() => {
    if (!problem?.llm_profile_json) return null;
@@ -392,8 +407,14 @@ export default function ProblemDetailPage() {
    setShowSolutions(false);
    setSolutionData(null);
    setSolutionMsg("");
+    draftLatestRef.current = { code: starterCode, stdin: defaultRunInput };
+    draftLastSavedSigRef.current = buildDraftSignature(starterCode, defaultRunInput);
  }, [id]);

+  useEffect(() => {
+    draftLatestRef.current = { code, stdin: runInput };
+  }, [code, runInput]);
+
  useEffect(() => {
    const clearPrintCache = () => setPrintAnswerMarkdown("");
    window.addEventListener("afterprint", clearPrintCache);
@@ -477,9 +498,21 @@ export default function ProblemDetailPage() {
      if (!token) return;
      try {
        const draft = await apiFetch<DraftResp>(`/api/v1/problems/${id}/draft`, undefined, token);
-        if (draft.code) setCode(draft.code);
-        if (draft.stdin) setRunInput(draft.stdin);
-        setDraftMsg(tx("已自动加载草稿", "Draft auto-loaded"));
+        const hasDraft = Boolean(draft.exists) || Boolean(draft.code) || Boolean(draft.stdin);
+        let nextCode = draftLatestRef.current.code;
+        let nextStdin = draftLatestRef.current.stdin;
+        if (draft.code) {
+          nextCode = draft.code;
+          setCode(draft.code);
+        }
+        if (typeof draft.stdin === "string" && draft.stdin.length > 0) {
+          nextStdin = draft.stdin;
+          setRunInput(draft.stdin);
+        }
+        draftLastSavedSigRef.current = buildDraftSignature(nextCode, nextStdin);
+        if (hasDraft) {
+          setDraftMsg(tx("已自动加载草稿", "Draft auto-loaded"));
+        }
      } catch {
        // ignore empty draft / unauthorized
      }
@@ -487,6 +520,39 @@ export default function ProblemDetailPage() {
    void loadDraft();
  }, [id, tx]);

+  useEffect(() => {
+    if (!Number.isFinite(id) || id <= 0) return;
+    const timer = window.setInterval(() => {
+      const token = readToken();
+      if (!token || draftAutoSavingRef.current) return;
+
+      const payload = draftLatestRef.current;
+      const nextSig = buildDraftSignature(payload.code, payload.stdin);
+      if (nextSig === draftLastSavedSigRef.current) return;
+
+      draftAutoSavingRef.current = true;
+      void apiFetch<{ saved: boolean }>(
+        `/api/v1/problems/${id}/draft`,
+        {
+          method: "PUT",
+          body: JSON.stringify({ language: "cpp", code: payload.code, stdin: payload.stdin }),
+        },
+        token
+      )
+        .then(() => {
+          draftLastSavedSigRef.current = nextSig;
+          setDraftMsg(tx("草稿已自动保存（每60秒）", "Draft auto-saved (every 60s)"));
+        })
+        .catch(() => {
+          // Keep silent to avoid noisy notifications on transient network errors.
+        })
+        .finally(() => {
+          draftAutoSavingRef.current = false;
+        });
+    }, 60000);
+    return () => window.clearInterval(timer);
+  }, [id, tx]);
+
  useEffect(() => {
    if (!problemId) return;
    setRunInput((prev) => (prev.trim().length > 0 ? prev : sampleInput || defaultRunInput));
@@ -555,6 +621,7 @@ export default function ProblemDetailPage() {
        },
        token
      );
+      draftLastSavedSigRef.current = buildDraftSignature(code, runInput);
      setDraftMsg(tx("草稿已保存", "Draft saved"));
    } catch (e: unknown) {
      setError(String(e));
@@ -1084,7 +1151,7 @@ export default function ProblemDetailPage() {
                              {tx("写入并试运行", "Insert & Run")}
                            </button>
                          </div>
-                          <pre className="overflow-x-auto whitespace-pre p-3 text-sm leading-6 text-zinc-100">
+                          <pre className="solution-code-block overflow-x-auto whitespace-pre p-3 text-sm leading-6 text-zinc-100">
                            {normalizeCodeText(item.code_cpp)}
                          </pre>
                        </div>
--- a/frontend/src/components/app-nav.tsx
+++ b/frontend/src/components/app-nav.tsx
@@ -3,6 +3,7 @@
 import { usePathname, useRouter } from "next/navigation";
 import { useEffect, useMemo, useRef, useState } from "react";

+import { PixelAvatar } from "@/components/pixel-avatar";
 import { useUiPreferences } from "@/components/ui-preference-provider";
 import { apiFetch } from "@/lib/api";
 import { clearToken, readToken } from "@/lib/auth";
@@ -19,6 +20,11 @@ type NavGroup = {
  links: NavLink[];
 };

+type MeProfile = {
+  id?: number;
+  username?: string;
+};
+
 function buildNavGroups(t: (key: string) => string, isAdmin: boolean): NavGroup[] {
  const groups: NavGroup[] = [
    {
@@ -97,12 +103,13 @@ export function AppNav() {

  const [hasToken, setHasToken] = useState<boolean>(() => Boolean(readToken()));
  const [isAdmin, setIsAdmin] = useState(false);
+  const [meProfile, setMeProfile] = useState<MeProfile | null>(null);
  const [menuOpen, setMenuOpen] = useState(false);
  const [desktopOpenGroup, setDesktopOpenGroup] = useState<string | null>(null);
  const desktopMenuRef = useRef<HTMLDivElement | null>(null);
  const navGroups = useMemo(() => buildNavGroups(t, isAdmin), [isAdmin, t]);
  const activeGroup = resolveActiveGroup(pathname, navGroups);
-  const usePopupSecondary = theme === "default";
+  const usePopupSecondary = theme === "default" || theme === "minecraft";

  useEffect(() => {
    let canceled = false;
@@ -112,15 +119,20 @@ export function AppNav() {
      setHasToken(Boolean(token));
      if (!token) {
        setIsAdmin(false);
+        setMeProfile(null);
        return;
      }
      try {
-        const me = await apiFetch<{ username?: string }>("/api/v1/me", {}, token);
+        const me = await apiFetch<MeProfile>("/api/v1/me", {}, token);
        if (!canceled) {
          setIsAdmin((me?.username ?? "") === "admin");
+          setMeProfile(me ?? null);
        }
      } catch {
-        if (!canceled) setIsAdmin(false);
+        if (!canceled) {
+          setIsAdmin(false);
+          setMeProfile(null);
+        }
      }
    };
    const onRefresh = () => {
@@ -149,6 +161,16 @@ export function AppNav() {
  }, [desktopOpenGroup, usePopupSecondary]);

  const currentGroup = navGroups.find((g) => g.key === activeGroup) ?? navGroups[0];
+  const avatarSeed = meProfile
+    ? `${meProfile.username ?? "user"}-${meProfile.id ?? ""}`
+    : "guest";
+  const handleLogout = () => {
+    clearToken();
+    setHasToken(false);
+    setIsAdmin(false);
+    setMeProfile(null);
+    setDesktopOpenGroup(null);
+  };

  return (
    <header className="print-hidden border-b bg-[color:var(--surface)]/95 backdrop-blur supports-[backdrop-filter]:bg-[color:var(--surface)]/85">
@@ -188,7 +210,11 @@ export function AppNav() {
                        {group.label}
                      </button>
                      {opened && (
-                        <div className="absolute left-0 top-full z-50 mt-2 min-w-[11rem] rounded-md border bg-[color:var(--surface)] p-1 shadow-lg">
+                        <div
+                          className={`absolute left-0 top-full z-50 mt-2 rounded-md border bg-[color:var(--surface)] p-1 shadow-lg ${
+                            group.key === "account" ? "min-w-[18rem]" : "min-w-[11rem]"
+                          }`}
+                        >
                          {group.links.map((item) => {
                            const linkActive = isActivePath(pathname, item.href);
                            return (
@@ -207,6 +233,64 @@ export function AppNav() {
                              </button>
                            );
                          })}
+                          {group.key === "account" && (
+                            <div className="mt-2 space-y-2 border-t border-zinc-200 px-2 pt-2">
+                              <label className="block text-xs">
+                                <span className="text-zinc-500">{t("prefs.theme")}</span>
+                                <select
+                                  className="mt-1 w-full rounded-md border px-2 py-1 text-xs"
+                                  value={theme}
+                                  onChange={(e) => setTheme(e.target.value as ThemeId)}
+                                >
+                                  {themes.map((item) => (
+                                    <option key={item.id} value={item.id}>
+                                      {item.labels[language]}
+                                    </option>
+                                  ))}
+                                </select>
+                              </label>
+                              <label className="block text-xs">
+                                <span className="text-zinc-500">{t("prefs.language")}</span>
+                                <select
+                                  className="mt-1 w-full rounded-md border px-2 py-1 text-xs"
+                                  value={language}
+                                  onChange={(e) => setLanguage(e.target.value === "zh" ? "zh" : "en")}
+                                >
+                                  <option value="en">{t("prefs.lang.en")}</option>
+                                  <option value="zh">{t("prefs.lang.zh")}</option>
+                                </select>
+                              </label>
+                              <div className="flex items-center justify-between gap-2 rounded-md border border-zinc-200 px-2 py-1.5">
+                                <div className="flex min-w-0 items-center gap-2">
+                                  <span className={hasToken ? "text-emerald-700" : "text-zinc-500"}>
+                                    {hasToken ? t("nav.logged_in") : t("nav.logged_out")}
+                                  </span>
+                                  {hasToken && (
+                                    <>
+                                      <PixelAvatar
+                                        seed={avatarSeed}
+                                        size={20}
+                                        className="border-zinc-700"
+                                        alt={meProfile?.username ? `${meProfile.username} avatar` : "avatar"}
+                                      />
+                                      {meProfile?.username && (
+                                        <span className="truncate text-xs text-zinc-500">{meProfile.username}</span>
+                                      )}
+                                    </>
+                                  )}
+                                </div>
+                                {hasToken && (
+                                  <button
+                                    type="button"
+                                    className="rounded-md border px-2 py-1 text-xs hover:bg-zinc-100"
+                                    onClick={handleLogout}
+                                  >
+                                    {t("nav.logout")}
+                                  </button>
+                                )}
+                              </div>
+                            </div>
+                          )}
                        </div>
                      )}
                    </div>
@@ -274,7 +358,7 @@ export function AppNav() {
          </div>
        </div>

-        <div className="mt-2 flex flex-wrap items-center justify-end gap-2 text-xs sm:text-sm">
+        <div className={`mt-2 flex flex-wrap items-center justify-end gap-2 text-xs sm:text-sm ${usePopupSecondary ? "md:hidden" : ""}`}>
          <label className="inline-flex items-center gap-1">
            <span className="text-zinc-500">{t("prefs.theme")}</span>
            <select
@@ -306,13 +390,17 @@ export function AppNav() {
          <span className={hasToken ? "text-emerald-700" : "text-zinc-500"}>
            {hasToken ? t("nav.logged_in") : t("nav.logged_out")}
          </span>
+          {hasToken && (
+            <PixelAvatar
+              seed={avatarSeed}
+              size={24}
+              className="border-zinc-700"
+              alt={meProfile?.username ? `${meProfile.username} avatar` : "avatar"}
+            />
+          )}
          {hasToken && (
            <button
-              onClick={() => {
-                clearToken();
-                setHasToken(false);
-                setIsAdmin(false);
-              }}
+              onClick={handleLogout}
              className="rounded-md border px-3 py-1 hover:bg-zinc-100"
            >
              {t("nav.logout")}
--- a/frontend/src/components/code-editor.tsx
+++ b/frontend/src/components/code-editor.tsx
@@ -4,11 +4,13 @@ import dynamic from "next/dynamic";
 import { useCallback, useEffect, useRef } from "react";
 import type { editor as MonacoEditorNS, IDisposable, MarkerSeverity, IPosition } from "monaco-editor";

+import { useUiPreferences } from "@/components/ui-preference-provider";
 import { analyzeCpp14Policy, type Cpp14PolicyIssue } from "@/lib/cpp14-policy";
 import { useI18nText } from "@/lib/i18n";

 const MonacoEditor = dynamic(() => import("@monaco-editor/react"), { ssr: false });
 const POLICY_MARKER_OWNER = "csp-cpp14-policy";
+const MINECRAFT_MONACO_THEME = "csp-minecraft-dark";

 type Props = {
  value: string;
@@ -94,6 +96,40 @@ function localizePolicyIssue(
  return { ...issue, ...localized };
 }

+function defineMinecraftMonacoTheme(monaco: typeof import("monaco-editor")): void {
+  monaco.editor.defineTheme(MINECRAFT_MONACO_THEME, {
+    base: "vs-dark",
+    inherit: true,
+    rules: [
+      { token: "", foreground: "ECECEC", background: "111317" },
+      { token: "comment", foreground: "7F8A99", fontStyle: "italic" },
+      { token: "keyword", foreground: "C792EA" },
+      { token: "type", foreground: "82AAFF" },
+      { token: "number", foreground: "F78C6C" },
+      { token: "string", foreground: "C3E88D" },
+      { token: "operator", foreground: "89DDFF" },
+      { token: "delimiter.bracket", foreground: "D8DEE9" },
+      { token: "predefined", foreground: "FFD580" },
+    ],
+    colors: {
+      "editor.background": "#111317",
+      "editor.foreground": "#ECECEC",
+      "editorCursor.foreground": "#FFE082",
+      "editorLineNumber.foreground": "#768296",
+      "editorLineNumber.activeForeground": "#C7D0DE",
+      "editor.selectionBackground": "#2A3347",
+      "editor.inactiveSelectionBackground": "#232B3C",
+      "editor.lineHighlightBackground": "#171D26",
+      "editor.wordHighlightBackground": "#303A4E99",
+      "editorIndentGuide.background": "#2A3240",
+      "editorIndentGuide.activeBackground": "#3D485A",
+      "editorBracketMatch.background": "#2B364A",
+      "editorBracketMatch.border": "#89DDFF88",
+      "editorGutter.background": "#111317",
+    },
+  });
+}
+
 export function CodeEditor({
  value,
  onChange,
@@ -101,10 +137,12 @@ export function CodeEditor({
  fontSize = 14,
  onPolicyIssuesChange,
 }: Props) {
+  const { theme } = useUiPreferences();
  const { tx } = useI18nText();
  const editorRef = useRef<MonacoEditorNS.IStandaloneCodeEditor | null>(null);
  const monacoRef = useRef<typeof import("monaco-editor") | null>(null);
  const completionRef = useRef<IDisposable | null>(null);
+  const editorTheme = theme === "minecraft" ? MINECRAFT_MONACO_THEME : "vs";

  const updatePolicyIssues = useCallback(
    (nextCode: string) => {
@@ -145,10 +183,20 @@ export function CodeEditor({
    []
  );

+  useEffect(() => {
+    const monaco = monacoRef.current;
+    if (!monaco) return;
+    if (editorTheme === MINECRAFT_MONACO_THEME) {
+      defineMinecraftMonacoTheme(monaco);
+    }
+    monaco.editor.setTheme(editorTheme);
+  }, [editorTheme]);
+
  return (
    <MonacoEditor
      height={height}
      language="cpp"
+      theme={editorTheme}
      value={value}
      options={{
        fontSize,
@@ -167,6 +215,10 @@ export function CodeEditor({
      onMount={(editor, monaco) => {
        editorRef.current = editor;
        monacoRef.current = monaco;
+        if (editorTheme === MINECRAFT_MONACO_THEME) {
+          defineMinecraftMonacoTheme(monaco);
+        }
+        monaco.editor.setTheme(editorTheme);

        if (!completionRef.current) {
          completionRef.current = monaco.languages.registerCompletionItemProvider("cpp", {
--- a/frontend/src/components/pixel-avatar.tsx
+++ b/frontend/src/components/pixel-avatar.tsx
@@ -0,0 +1,39 @@
+"use client";
+
+import Image from "next/image";
+import { useMemo } from "react";
+
+import { buildAvatarSeed, generatePixelAvatarDataUri } from "@/lib/pixel-avatar";
+
+type PixelAvatarProps = {
+  seed: string;
+  size?: number;
+  className?: string;
+  alt?: string;
+};
+
+export function PixelAvatar({
+  seed,
+  size = 40,
+  className = "",
+  alt = "pixel avatar",
+}: PixelAvatarProps) {
+  const resolvedSeed = useMemo(() => buildAvatarSeed(seed), [seed]);
+  const src = useMemo(() => generatePixelAvatarDataUri(resolvedSeed), [resolvedSeed]);
+
+  return (
+    <span
+      className={`pixel-avatar-frame inline-flex items-center justify-center overflow-hidden rounded border ${className}`.trim()}
+      style={{ width: size, height: size }}
+    >
+      <Image
+        src={src}
+        alt={alt}
+        width={size}
+        height={size}
+        unoptimized
+        className="pixel-avatar-image h-full w-full object-cover"
+      />
+    </span>
+  );
+}
--- a/frontend/src/lib/api.ts
+++ b/frontend/src/lib/api.ts
@@ -3,9 +3,9 @@ export const API_BASE =
  (process.env.NODE_ENV === "development" ? "http://localhost:8080" : "/admin139");

 function uiText(zhText: string, enText: string): string {
-  if (typeof window === "undefined") return enText;
+  if (typeof window === "undefined") return zhText;
  const lang = window.localStorage.getItem("csp.ui.language");
-  return lang === "zh" ? zhText : enText;
+  return lang === "en" ? enText : zhText;
 }

 type ApiEnvelope<T> =
--- a/frontend/src/lib/cpp14-policy.ts
+++ b/frontend/src/lib/cpp14-policy.ts
@@ -186,21 +186,5 @@ export function analyzeCpp14Policy(code: string): Cpp14PolicyIssue[] {
    );
  }

-  if (!/\bfreopen\s*\(/.test(text) && /\bint\s+main\s*\(/.test(text)) {
-    const idx = text.search(/\bint\s+main\s*\(/);
-    const pos = offsetToPosition(lineStarts, Math.max(0, idx));
-    pushIssue(
-      issues,
-      "freopen-tip",
-      "hint",
-      "未检测到 freopen（福建二轮常见文件读写要求）",
-      "若考场题面要求 *.in/*.out，请按官方文件名补上 freopen。",
-      pos.line,
-      pos.column,
-      pos.line,
-      pos.column + 3
-    );
-  }
-
  return issues;
 }
--- a/frontend/src/lib/i18n.ts
+++ b/frontend/src/lib/i18n.ts
@@ -1,15 +1,20 @@
 "use client";

+import { useCallback } from "react";
+
 import { useUiPreferences } from "@/components/ui-preference-provider";

 export function readUiLanguage(): "en" | "zh" {
-  if (typeof window === "undefined") return "en";
-  return window.localStorage.getItem("csp.ui.language") === "zh" ? "zh" : "en";
+  if (typeof window === "undefined") return "zh";
+  return window.localStorage.getItem("csp.ui.language") === "en" ? "en" : "zh";
 }

 export function useI18nText() {
  const { language } = useUiPreferences();
  const isZh = language === "zh";
-  const tx = (zhText: string, enText: string) => (isZh ? zhText : enText);
+  const tx = useCallback(
+    (zhText: string, enText: string) => (isZh ? zhText : enText),
+    [isZh]
+  );
  return { language, isZh, tx };
 }
--- a/frontend/src/lib/pixel-avatar.ts
+++ b/frontend/src/lib/pixel-avatar.ts
@@ -0,0 +1,74 @@
+function hashSeed(seed: string): number {
+  let h = 2166136261 >>> 0;
+  for (let i = 0; i < seed.length; i += 1) {
+    h ^= seed.charCodeAt(i);
+    h = Math.imul(h, 16777619) >>> 0;
+  }
+  return h >>> 0;
+}
+
+function mulberry32(seed: number): () => number {
+  let t = seed >>> 0;
+  return () => {
+    t += 0x6d2b79f5;
+    let x = Math.imul(t ^ (t >>> 15), t | 1);
+    x ^= x + Math.imul(x ^ (x >>> 7), x | 61);
+    return ((x ^ (x >>> 14)) >>> 0) / 4294967296;
+  };
+}
+
+const SKIN_PALETTE = ["#f6d3b3", "#e6be95", "#d7a980", "#f8dec6", "#c99264"];
+const HAIR_PALETTE = ["#2f1b12", "#4a2f1d", "#6d4c41", "#212121", "#4e342e", "#1b5e20"];
+const ACCENT_PALETTE = ["#7cb342", "#00b0d6", "#ffb300", "#8d6e63", "#ab47bc", "#ef5350"];
+
+export function buildAvatarSeed(...parts: Array<string | number | null | undefined>): string {
+  const cleaned = parts
+    .map((part) => String(part ?? "").trim())
+    .filter((part) => part.length > 0);
+  return cleaned.length > 0 ? cleaned.join("|") : "guest|pixel";
+}
+
+export function generatePixelAvatarDataUri(seedInput: string, pixelSize = 10): string {
+  const seed = buildAvatarSeed(seedInput);
+  const rng = mulberry32(hashSeed(seed));
+  const skin = SKIN_PALETTE[Math.floor(rng() * SKIN_PALETTE.length)] ?? SKIN_PALETTE[0];
+  const hair = HAIR_PALETTE[Math.floor(rng() * HAIR_PALETTE.length)] ?? HAIR_PALETTE[0];
+  const accent = ACCENT_PALETTE[Math.floor(rng() * ACCENT_PALETTE.length)] ?? ACCENT_PALETTE[0];
+  const bg = rng() > 0.5 ? "#1f1f1f" : "#2b2b2b";
+  const border = rng() > 0.5 ? "#000000" : "#3e2723";
+
+  const width = 8 * pixelSize;
+  const height = 8 * pixelSize;
+  const rects: string[] = [
+    `<rect width="${width}" height="${height}" fill="${bg}"/>`,
+    `<rect x="0" y="0" width="${width}" height="${pixelSize}" fill="${accent}" opacity="0.4"/>`,
+  ];
+
+  for (let y = 0; y < 8; y += 1) {
+    for (let x = 0; x < 4; x += 1) {
+      const fillFace = y >= 1 && y <= 6 && x >= 1;
+      const threshold = fillFace ? 0.2 : 0.52;
+      if (rng() < threshold) continue;
+
+      const color = y <= 1 ? hair : y >= 6 ? accent : skin;
+      const leftX = x * pixelSize;
+      const rightX = (7 - x) * pixelSize;
+      const yPos = y * pixelSize;
+      rects.push(`<rect x="${leftX}" y="${yPos}" width="${pixelSize}" height="${pixelSize}" fill="${color}"/>`);
+      if (rightX !== leftX) {
+        rects.push(`<rect x="${rightX}" y="${yPos}" width="${pixelSize}" height="${pixelSize}" fill="${color}"/>`);
+      }
+    }
+  }
+
+  const eyeY = 3 * pixelSize;
+  rects.push(`<rect x="${2 * pixelSize}" y="${eyeY}" width="${pixelSize}" height="${pixelSize}" fill="#111"/>`);
+  rects.push(`<rect x="${5 * pixelSize}" y="${eyeY}" width="${pixelSize}" height="${pixelSize}" fill="#111"/>`);
+
+  const mouthY = 5 * pixelSize;
+  rects.push(`<rect x="${3 * pixelSize}" y="${mouthY}" width="${2 * pixelSize}" height="${pixelSize}" fill="${hair}" opacity="0.8"/>`);
+  rects.push(`<rect x="${0}" y="${0}" width="${width}" height="${height}" fill="none" stroke="${border}" stroke-width="${Math.max(2, Math.floor(pixelSize / 4))}"/>`);
+
+  const svg = `<svg xmlns="http://www.w3.org/2000/svg" width="${width}" height="${height}" viewBox="0 0 ${width} ${height}" shape-rendering="crispEdges">${rects.join("")}</svg>`;
+  return `data:image/svg+xml;utf8,${encodeURIComponent(svg)}`;
+}
--- a/frontend/src/themes/README.md
+++ b/frontend/src/themes/README.md
@@ -247,6 +247,8 @@ labels: {
 来源参考：

 - `ref/CSP-Minecraft-UI-Kit/docs/Design-Delivery-Document.html`
+- `ref/CSP-Minecraft-UI-Kit/html/index.html`
+- `ref/CSP-Minecraft-UI-Kit/html/pages/*.html`

 已落地核心规范：

@@ -256,6 +258,7 @@ labels: {
 - 输入控件像素化风格。
 - 背景纹理与图片 `image-rendering: pixelated`。
 - 标题字体与文本阴影风格。
+- 像素默认头像（按账号随机种子生成）。

 ---

@@ -291,4 +294,3 @@ labels: {
 - 将“按钮、卡片、输入框、徽章”收敛为主题化组件（而非纯 class 覆盖）。
 - 增加主题视觉回归截图（关键页面自动快照）。
 - 建立对比度检测脚本，避免低对比度文本上线。
-
--- a/frontend/src/themes/minecraft/theme.css
+++ b/frontend/src/themes/minecraft/theme.css
@@ -1,49 +1,51 @@
@font-face {
-  font-family: "DelaGothicOne";
-  src: url("https://assets-persist.lovart.ai/agent-static-assets/DelaGothicOne-Regular.ttf");
+  font-family: "PressStart2P";
+  src: url("https://fonts.gstatic.com/s/pressstart2p/v15/e3t4euO8T-267oIAQAu6jDQyK3nVivM.woff2")
+    format("woff2");
  font-display: swap;
 }

@font-face {
-  font-family: "MiSans";
-  src: url("https://assets-persist.lovart.ai/agent-static-assets/MiSans-Regular.ttf");
-  font-display: swap;
-}
-
-@font-face {
-  font-family: "MiSansBold";
-  src: url("https://assets-persist.lovart.ai/agent-static-assets/MiSans-Bold.ttf");
+  font-family: "VT323";
+  src: url("https://fonts.gstatic.com/s/vt323/v17/pxiKyp0ihIEF2hsY.woff2") format("woff2");
  font-display: swap;
 }

 :root[data-theme="minecraft"] {
-  --mc-grass-top: #5cb85c;
-  --mc-grass-side: #4cae4c;
+  --mc-grass-top: #7cb342;
+  --mc-grass-dark: #558b2f;
  --mc-dirt: #795548;
+  --mc-wood-dark: #5d4037;
+  --mc-wood: #8d6e63;
+  --mc-plank: #c69c6d;
+  --mc-plank-light: #efebe9;
  --mc-stone: #9e9e9e;
  --mc-stone-dark: #616161;
-  --mc-obsidian: #212121;
-  --mc-wood: #8d6e63;
-  --mc-wood-dark: #5d4037;
-  --mc-gold: #ffd700;
-  --mc-diamond: #40e0d0;
-  --mc-redstone: #f44336;
+  --mc-obsidian: #1f1f1f;
+  --mc-diamond: #00b0d6;
+  --mc-gold: #ffb300;
+  --mc-red: #ef5350;
+  --mc-shadow: #000000;

-  --background: #1a1a1a;
+  --background: #161616;
  --foreground: #f5f5f5;
-  --surface: #2d2d2d;
-  --surface-soft: #242424;
+  --surface: #262626;
+  --surface-soft: #1f1f1f;
  --border: #000000;
 }

 :root[data-theme="minecraft"] body {
  background-color: var(--background);
  background-image:
-    linear-gradient(rgba(26, 26, 26, 0.9), rgba(26, 26, 26, 0.9)),
-    url("https://a.lovart.ai/artifacts/agent/W1iXxVdg3xIm5fP9.png");
-  background-size: 320px 320px;
+    linear-gradient(45deg, #1f1f1f 25%, transparent 25%),
+    linear-gradient(-45deg, #1f1f1f 25%, transparent 25%),
+    linear-gradient(45deg, transparent 75%, #1f1f1f 75%),
+    linear-gradient(-45deg, transparent 75%, #1f1f1f 75%);
+  background-size: 40px 40px;
+  background-position: 0 0, 0 20px, 20px -20px, -20px 0;
  color: var(--foreground);
-  font-family: "MiSans", "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
+  font-family: "VT323", "MiSans", "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
+  font-size: 1.06rem;
 }

 :root[data-theme="minecraft"] h1,
@@ -52,9 +54,9 @@
 :root[data-theme="minecraft"] h4,
 :root[data-theme="minecraft"] h5,
 :root[data-theme="minecraft"] h6 {
-  color: #ffffff;
-  font-family: "DelaGothicOne", "MiSansBold", "MiSans", sans-serif;
+  font-family: "PressStart2P", "VT323", sans-serif;
  letter-spacing: 0.04em;
+  line-height: 1.5;
  text-shadow: 2px 2px 0 #000000;
 }

@@ -65,19 +67,35 @@
 }

 :root[data-theme="minecraft"] ::-webkit-scrollbar-thumb {
-  background: var(--mc-stone);
-  border: 2px solid var(--mc-obsidian);
+  background: var(--mc-wood);
+  border: 2px solid #000;
+}
+
+:root[data-theme="minecraft"] .print-hidden {
+  image-rendering: pixelated;
 }

 :root[data-theme="minecraft"] header.print-hidden {
-  background: rgba(33, 33, 33, 0.96) !important;
-  border-bottom: 4px solid var(--mc-stone-dark);
-  box-shadow: 0 4px 0 rgba(0, 0, 0, 0.35);
+  background: linear-gradient(180deg, #1d1d1d 0%, #2b2b2b 100%) !important;
+  border-bottom: 4px solid #000 !important;
+  box-shadow: 0 6px 0 rgba(0, 0, 0, 0.4);
+  position: relative;
+}
+
+:root[data-theme="minecraft"] header.print-hidden::before {
+  content: "";
+  position: absolute;
+  left: 0;
+  top: 0;
+  width: 100%;
+  height: 8px;
+  background: linear-gradient(180deg, var(--mc-grass-top) 0%, var(--mc-grass-dark) 100%);
+  border-bottom: 2px solid #2e7d32;
 }

 :root[data-theme="minecraft"] nav.print-hidden.fixed {
-  background: rgba(33, 33, 33, 0.96) !important;
-  border-top: 4px solid var(--mc-stone-dark);
+  background: linear-gradient(180deg, #1d1d1d 0%, #2b2b2b 100%) !important;
+  border-top: 4px solid #000;
 }

 :root[data-theme="minecraft"] .rounded-xl.border,
@@ -85,28 +103,39 @@
 :root[data-theme="minecraft"] .rounded-md.border,
 :root[data-theme="minecraft"] .rounded.border {
  border-radius: 0 !important;
-  border-color: #000000 !important;
-  border-width: 3px !important;
-  box-shadow: 6px 6px 0 rgba(0, 0, 0, 0.45);
+  border: 3px solid #000 !important;
+  box-shadow:
+    5px 5px 0 rgba(0, 0, 0, 0.48),
+    inset 2px 2px 0 rgba(255, 255, 255, 0.08);
+}
+
+:root[data-theme="minecraft"] main section.rounded-xl.border.bg-white,
+:root[data-theme="minecraft"] main article.rounded-xl.border.bg-white {
+  background: linear-gradient(180deg, #2a2a2a 0%, #232323 100%) !important;
 }

 :root[data-theme="minecraft"] .bg-white {
-  background-color: #2d2d2d !important;
+  background-color: #292929 !important;
 }

 :root[data-theme="minecraft"] .bg-zinc-50 {
-  background-color: #252525 !important;
+  background-color: #242424 !important;
 }

 :root[data-theme="minecraft"] .bg-zinc-100 {
-  background-color: #343434 !important;
+  background-color: #323232 !important;
 }

 :root[data-theme="minecraft"] .text-zinc-400,
 :root[data-theme="minecraft"] .text-zinc-500,
 :root[data-theme="minecraft"] .text-zinc-600,
 :root[data-theme="minecraft"] .text-zinc-700 {
-  color: #d0d0d0 !important;
+  color: #d7d7d7 !important;
+}
+
+:root[data-theme="minecraft"] .text-zinc-800,
+:root[data-theme="minecraft"] .text-zinc-900 {
+  color: #ececec !important;
 }

 :root[data-theme="minecraft"] .text-blue-600,
@@ -125,24 +154,26 @@

 :root[data-theme="minecraft"] .text-red-600,
 :root[data-theme="minecraft"] .text-red-700 {
-  color: var(--mc-redstone) !important;
+  color: var(--mc-red) !important;
 }

 :root[data-theme="minecraft"] button {
-  background: linear-gradient(180deg, var(--mc-stone) 0%, var(--mc-stone-dark) 100%) !important;
-  border: 3px solid #000000 !important;
+  background: linear-gradient(180deg, var(--mc-wood) 0%, var(--mc-wood-dark) 100%) !important;
+  border: 3px solid #000 !important;
  border-bottom-width: 7px !important;
  border-radius: 0 !important;
-  box-shadow: 4px 4px 0 rgba(0, 0, 0, 0.45);
-  color: #ffffff !important;
-  font-family: "DelaGothicOne", "MiSansBold", "MiSans", sans-serif;
-  letter-spacing: 0.03em;
-  text-shadow: 1px 1px 0 #000000;
+  color: #fff !important;
+  font-family: "PressStart2P", "VT323", sans-serif !important;
+  font-size: 0.62rem !important;
+  letter-spacing: 0.04em;
+  line-height: 1.4;
+  text-shadow: 1px 1px 0 #000;
+  box-shadow: 4px 4px 0 rgba(0, 0, 0, 0.48);
  transition: transform 0.08s ease, filter 0.08s ease;
 }

 :root[data-theme="minecraft"] button:hover:not(:disabled) {
-  filter: brightness(1.08);
+  filter: brightness(1.07);
  transform: translateY(-1px);
 }

@@ -152,23 +183,25 @@
 }

 :root[data-theme="minecraft"] button:disabled {
-  filter: saturate(0.25);
-  opacity: 0.7;
+  opacity: 0.68;
+  filter: saturate(0.28);
 }

 :root[data-theme="minecraft"] input,
 :root[data-theme="minecraft"] textarea,
 :root[data-theme="minecraft"] select {
  background: #1f1f1f !important;
-  border: 3px solid #000000 !important;
+  border: 3px solid #000 !important;
  border-radius: 0 !important;
-  box-shadow: inset 2px 2px 0 rgba(255, 255, 255, 0.1);
-  color: #f2f2f2 !important;
+  color: #f4f4f4 !important;
+  box-shadow: inset 2px 2px 0 rgba(255, 255, 255, 0.12);
+  font-family: "VT323", "MiSans", sans-serif;
+  font-size: 1rem;
 }

 :root[data-theme="minecraft"] input::placeholder,
 :root[data-theme="minecraft"] textarea::placeholder {
-  color: #acacac;
+  color: #adadad;
 }

 :root[data-theme="minecraft"] a {
@@ -180,22 +213,80 @@
 }

 :root[data-theme="minecraft"] table thead {
-  background: #333333 !important;
+  background: #353535 !important;
 }

 :root[data-theme="minecraft"] table tr {
-  border-color: #000000 !important;
+  border-color: #000 !important;
 }

 :root[data-theme="minecraft"] pre {
-  border: 2px solid #000000;
+  border: 2px solid #000;
  box-shadow: inset 1px 1px 0 rgba(255, 255, 255, 0.08);
 }

+:root[data-theme="minecraft"] code {
+  font-family: "VT323", ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
+}
+
+:root[data-theme="minecraft"] .monaco-editor,
+:root[data-theme="minecraft"] .monaco-editor .margin,
+:root[data-theme="minecraft"] .monaco-editor .monaco-editor-background,
+:root[data-theme="minecraft"] .monaco-editor-background,
+:root[data-theme="minecraft"] .monaco-editor .inputarea.ime-input {
+  background-color: #111317 !important;
+}
+
+:root[data-theme="minecraft"] .monaco-editor .current-line {
+  border-color: #232b3c !important;
+}
+
+:root[data-theme="minecraft"] .monaco-editor .suggest-widget,
+:root[data-theme="minecraft"] .monaco-editor .parameter-hints-widget {
+  border: 2px solid #000 !important;
+  background: #161a22 !important;
+  color: #ececec !important;
+}
+
+:root[data-theme="minecraft"] .monaco-editor .suggest-widget .monaco-list-row.focused {
+  background: #2a3347 !important;
+}
+
 :root[data-theme="minecraft"] img {
  image-rendering: pixelated;
 }

+:root[data-theme="minecraft"] .pixel-avatar-frame {
+  border: 3px solid #000 !important;
+  border-radius: 0 !important;
+  background: linear-gradient(180deg, var(--mc-plank) 0%, var(--mc-dirt) 100%);
+  box-shadow:
+    3px 3px 0 rgba(0, 0, 0, 0.45),
+    inset 1px 1px 0 rgba(255, 255, 255, 0.18);
+}
+
+:root[data-theme="minecraft"] .pixel-avatar-image {
+  image-rendering: pixelated;
+}
+
 :root[data-theme="minecraft"] .problem-markdown-compact {
  font-size: 66%;
 }
+
+:root[data-theme="minecraft"] .problem-markdown-compact article {
+  color: #ececec !important;
+}
+
+:root[data-theme="minecraft"] .problem-markdown-compact blockquote {
+  color: #d9d9d9 !important;
+  border-left-color: #8d6e63 !important;
+}
+
+:root[data-theme="minecraft"] .problem-markdown-compact th,
+:root[data-theme="minecraft"] .problem-markdown-compact td {
+  color: #ececec !important;
+}
+
+:root[data-theme="minecraft"] .problem-markdown-compact th {
+  background: #3a3a3a !important;
+}
--- a/frontend/src/themes/types.ts
+++ b/frontend/src/themes/types.ts
@@ -2,7 +2,7 @@ export type ThemeId = "default" | "minecraft";
 export type UiLanguage = "en" | "zh";

 export const DEFAULT_THEME: ThemeId = "default";
-export const DEFAULT_LANGUAGE: UiLanguage = "en";
+export const DEFAULT_LANGUAGE: UiLanguage = "zh";

 export type ThemeMessages = Record<string, string>;