diff --git a/apps/api/src/index.ts b/apps/api/src/index.ts
index 51f5b12..d2f9b97 100644
--- a/apps/api/src/index.ts
+++ b/apps/api/src/index.ts
@@ -15,6 +15,7 @@ import { achievementRoutes } from "./routes/achievement"
 import { aiRoutes } from "./routes/ai"
 import { flowchartRoutes } from "./routes/flowchart"
 import { problemRoutes } from "./routes/problem"
+import { problemStatsRoutes } from "./routes/problem-stats"
 import { submissionRoutes } from "./routes/submission"
 import { trialRunRoutes } from "./routes/trial-run"
 import { siteRoutes } from "./routes/site"
@@ -40,6 +41,7 @@ app.route("/api", achievementRoutes)
 app.route("/api", aiRoutes)
 app.route("/api", flowchartRoutes)
 app.route("/api", problemRoutes)
+app.route("/api", problemStatsRoutes)
 app.route("/api", submissionRoutes)
 app.route("/api", trialRunRoutes)
 app.route("/api", judgeServerRoutes)
diff --git a/apps/api/src/routes/problem-stats.ts b/apps/api/src/routes/problem-stats.ts
new file mode 100644
index 0000000..74b2777
--- /dev/null
+++ b/apps/api/src/routes/problem-stats.ts
@@ -0,0 +1,259 @@
+import { type ProblemClassDetail, type ProblemStats } from "@oj2/contract"
+import { and, eq, isNotNull, sql } from "drizzle-orm"
+import { Hono } from "hono"
+
+import { optionalAuth, type AppEnv } from "../auth/middleware"
+import { db, schema } from "../db"
+import { failure, success } from "../http"
+import { JudgeStatus, UNJUDGED_RESULTS, type JudgeStatusValue } from "../judge/status"
+import { canAccessContest, contestDetailsAllowed, findAccessibleContest } from "../services/contest"
+import { accepted } from "../services/learning-stats"
+import { localTime } from "../time"
+import { isAdminRole, isTeacherOrAbove, queryInteger, stripClassPrefix } from "./helpers"
+
+export const problemStatsRoutes = new Hono<AppEnv>()
+
+/**
+ * 同一天班里至少这么多人交过，才算「这个班一起做过这题」。只看总人数不行：
+ * 2079 有个班 2 月里零星补做了 6 个人，比 12 月全班 26 人做的那次还「近」，默认就选成了它
+ */
+const CLASS_MIN_TRIED = 5
+
+const EMPTY: ProblemStats = {
+  locked: false,
+  tried: 0,
+  solved: 0,
+  tries: { one: 0, few: 0, many: 0 },
+  failures: [],
+  wrongAnswerFirstCase: 0,
+  me: null,
+  myClass: null,
+  classes: null,
+  classDetail: null,
+}
+
+// type 而不是 interface：db.execute 的泛型约束是 Record<string, unknown>，interface 不带索引签名
+type UserRow = {
+  user_id: number
+  username: string | null
+  class_name: string | null
+  attempts: number
+  /** 做对之前（含做对那次）交了几次；没做对就是全部次数 */
+  tries: number
+  solved: boolean
+  last_result: JudgeStatusValue
+  last_time: string
+}
+
+/**
+ * 题目页「统计」页签。id 是内部题号（problem.id）：比赛题的展示题号是 1、2、3，
+ * 拿 displayId 查会撞上同号的公开题（原来的「历年 AC 率」就是这么查错的）。
+ * `className` 只有老师用：选中哪个班看明细，不填就是最近做过这题的那个班。
+ */
+problemStatsRoutes.get("/problems/:id/stats", optionalAuth, async (c) => {
+  const user = c.get("user")
+  const id = queryInteger(c.req.param("id"), 0, { min: 1 })
+  const [problem] = await db
+    .select({
+      id: schema.problem.id,
+      contestId: schema.problem.contestId,
+      visible: schema.problem.visible,
+    })
+    .from(schema.problem)
+    .where(eq(schema.problem.id, id))
+    .limit(1)
+  if (!problem) return failure(c, 404, "problem-not-found", "Problem does not exist")
+
+  const inContest = problem.contestId !== null
+  if (inContest) {
+    const contest = await findAccessibleContest(user, problem.contestId!)
+    if (!contest) return failure(c, 404, "problem-not-found", "Problem does not exist")
+    const access = await canAccessContest(c, contest, "problems")
+    if (!access.ok) return failure(c, 403, access.code, access.message)
+    // 比赛没结束：别人几次做对、错在哪一律不给，和题目详情里计数归零同一个口径
+    if (!contestDetailsAllowed(user, contest)) {
+      return success(c, { ...EMPTY, locked: true } satisfies ProblemStats)
+    }
+  } else if (!problem.visible && !isAdminRole(user)) {
+    return failure(c, 404, "problem-not-found", "Problem does not exist")
+  }
+
+  const acceptedList = sql.join(
+    accepted.map((value) => sql`${value}`),
+    sql`, `,
+  )
+  const unjudgedList = sql.join(
+    UNJUDGED_RESULTS.map((value) => sql`${value}`),
+    sql`, `,
+  )
+  // 每人一行：窗口函数先给每条提交标上这个人第一次做对的时刻，再按人数到那一刻为止交了几次
+  const day = sql<string>`to_char(${localTime(schema.submission.createTime)}, 'YYYY-MM-DD')`
+  const [users, failureRows, firstCase, classDays] = await Promise.all([
+    db.execute<UserRow>(sql`
+      select s.user_id, u.username, u.class_name,
+        count(*)::int as attempts,
+        count(*) filter (where s.first_ac is null or s.create_time <= s.first_ac)::int as tries,
+        (min(s.first_ac) is not null) as solved,
+        (array_agg(s.result order by s.create_time desc))[1] as last_result,
+        max(s.create_time) as last_time
+      from (
+        select user_id, result, create_time,
+          min(create_time) filter (where result in (${acceptedList}))
+            over (partition by user_id) as first_ac
+        from ${schema.submission}
+        where problem_id = ${problem.id} and result not in (${unjudgedList})
+      ) s
+      left join ${schema.user} u on u.id = s.user_id
+      group by s.user_id, u.username, u.class_name
+    `),
+    db.execute<{ class_name: string | null; result: JudgeStatusValue; n: number }>(sql`
+      select u.class_name, s.result, count(*)::int as n
+      from ${schema.submission} s
+      left join ${schema.user} u on u.id = s.user_id
+      where s.problem_id = ${problem.id}
+        and s.result not in (${acceptedList})
+        and s.result not in (${unjudgedList})
+      group by u.class_name, s.result
+    `),
+    // 判题机按测试点回一个数组，test_case 是 "1"、"2"……
+    db.execute<{ n: number }>(sql`
+      select count(*)::int as n from ${schema.submission}
+      where problem_id = ${problem.id} and result = ${JudgeStatus.WRONG_ANSWER}
+        and jsonb_typeof(info->'data') = 'array'
+        and exists (
+          select 1 from jsonb_array_elements(info->'data') e
+          where e->>'test_case' = '1' and (e->>'result')::int <> 0
+        )
+    `),
+    // 每个班每天几个人交过，取人最多的那天当「这个班做这题的那天」
+    db
+      .select({
+        className: schema.user.className,
+        day,
+        users: sql<number>`count(distinct ${schema.submission.userId})::int`,
+      })
+      .from(schema.submission)
+      .innerJoin(schema.user, eq(schema.user.id, schema.submission.userId))
+      .where(and(eq(schema.submission.problemId, problem.id), isNotNull(schema.user.className)))
+      .groupBy(schema.user.className, day),
+  ])
+
+  const solvedUsers = users.filter((row) => row.solved)
+  const tries = { one: 0, few: 0, many: 0 }
+  for (const row of solvedUsers) {
+    if (row.tries <= 1) tries.one++
+    else if (row.tries <= 3) tries.few++
+    else tries.many++
+  }
+  const sortFailures = (map: Map<JudgeStatusValue, number>) =>
+    [...map].map(([result, count]) => ({ result, count })).sort((a, b) => b.count - a.count)
+  const siteFailures = new Map<JudgeStatusValue, number>()
+  for (const row of failureRows) {
+    siteFailures.set(row.result, (siteFailures.get(row.result) ?? 0) + row.n)
+  }
+
+  const mine = user ? users.find((row) => row.user_id === user.id) : undefined
+  const myClassName = !inContest && user?.className ? user.className : null
+  const classmates = myClassName ? users.filter((row) => row.class_name === myClassName) : []
+
+  let classes: ProblemStats["classes"] = null
+  let classDetail: ProblemClassDetail | null = null
+  if (!inContest && isTeacherOrAbove(user)) {
+    const byClass = new Map<string, UserRow[]>()
+    for (const row of users) {
+      if (!row.class_name) continue
+      byClass.set(row.class_name, [...(byClass.get(row.class_name) ?? []), row])
+    }
+    const peak = new Map<string, { day: string; users: number }>()
+    for (const row of classDays) {
+      const current = peak.get(row.className!)
+      const later = current && row.users === current.users && row.day > current.day
+      if (!current || row.users > current.users || later) {
+        peak.set(row.className!, { day: row.day, users: row.users })
+      }
+    }
+    const lessonClasses = [...byClass]
+      .filter(([className]) => (peak.get(className)?.users ?? 0) >= CLASS_MIN_TRIED)
+      .map(([className, rows]) => ({
+        className,
+        tried: rows.length,
+        solved: rows.filter((row) => row.solved).length,
+        day: peak.get(className)!.day,
+      }))
+      .sort((a, b) => b.day.localeCompare(a.day))
+    classes = lessonClasses
+    // 地址里指定的班不在列表里（零星几个人做过）也照样给明细
+    const wanted = c.req.query("className")?.trim()
+    const selected = wanted && byClass.has(wanted) ? wanted : lessonClasses[0]?.className
+    if (selected) {
+      classDetail = await buildClassDetail(
+        selected,
+        peak.get(selected)!.day,
+        byClass.get(selected)!,
+        failureRows,
+      )
+    }
+  }
+
+  return success(c, {
+    locked: false,
+    tried: users.length,
+    solved: solvedUsers.length,
+    tries,
+    failures: sortFailures(siteFailures),
+    wrongAnswerFirstCase: firstCase[0]?.n ?? 0,
+    me: user ? { attempts: mine?.attempts ?? 0, solved: mine?.solved ?? false } : null,
+    myClass: myClassName
+      ? {
+          className: myClassName,
+          tried: classmates.length,
+          solved: classmates.filter((row) => row.solved).length,
+        }
+      : null,
+    classes,
+    classDetail,
+  } satisfies ProblemStats)
+})
+
+async function buildClassDetail(
+  className: string,
+  day: string,
+  rows: UserRow[],
+  failureRows: { class_name: string | null; result: JudgeStatusValue; n: number }[],
+): Promise<ProblemClassDetail> {
+  // 花名册只数学生：老师、助教也可能挂着班级
+  const roster = await db
+    .select({ id: schema.user.id, username: schema.user.username })
+    .from(schema.user)
+    .where(
+      and(
+        eq(schema.user.className, className),
+        eq(schema.user.adminType, "Regular User"),
+        eq(schema.user.isDisabled, false),
+      ),
+    )
+  const triedIds = new Set(rows.map((row) => row.user_id))
+  const name = (username: string | null) => stripClassPrefix(username ?? "", className)
+  return {
+    className,
+    roster: roster.length,
+    day,
+    failures: failureRows
+      .filter((row) => row.class_name === className)
+      .map((row) => ({ result: row.result, count: row.n }))
+      .sort((a, b) => b.count - a.count),
+    unsolved: rows
+      .filter((row) => !row.solved)
+      .sort((a, b) => b.attempts - a.attempts)
+      .map((row) => ({
+        realName: name(row.username),
+        attempts: row.attempts,
+        lastResult: row.last_result,
+      })),
+    solved: rows
+      .filter((row) => row.solved)
+      .sort((a, b) => a.last_time.localeCompare(b.last_time))
+      .map((row) => name(row.username)),
+    untouched: roster.filter((row) => !triedIds.has(row.id)).map((row) => name(row.username)),
+  }
+}
diff --git a/apps/api/src/routes/problem.ts b/apps/api/src/routes/problem.ts
index ee6bff0..de0cf70 100644
--- a/apps/api/src/routes/problem.ts
+++ b/apps/api/src/routes/problem.ts
@@ -1,11 +1,4 @@
-import type {
-  ProblemAuthor,
-  ProblemDetail,
-  ProblemList,
-  ProblemListItem,
-  Tag,
-  YearlyAc,
-} from "@oj2/contract"
+import type { ProblemAuthor, ProblemDetail, ProblemList, ProblemListItem, Tag } from "@oj2/contract"
 import {
   and,
   asc,
@@ -13,7 +6,6 @@ import {
   countDistinct,
   desc,
   eq,
-  gte,
   ilike,
   inArray,
   isNull,
@@ -29,7 +21,6 @@ import { db, schema } from "../db"
 import { astRequirements } from "../judge/ast"
 import { failure, success } from "../http"
 import { JudgeStatus } from "../judge/status"
-import { dayStart, localTime, shiftMonthsByCalendar } from "../time"
 import {
   asFilterValue,
   countFailedSubmissions,
@@ -245,47 +236,6 @@ problemRoutes.get("/problem-authors", async (c) => {
   return success(c, rows satisfies ProblemAuthor[])
 })
 
-problemRoutes.get("/problems/:id/beat-count", optionalAuth, async (c) => {
-  const user = c.get("user")
-  if (!user) return success(c, "0")
-  const id = queryInteger(c.req.param("id"), 0, { min: 1 })
-  const [mine] = await db
-    .select({ value: count() })
-    .from(schema.submission)
-    .where(
-      and(
-        eq(schema.submission.userId, user.id),
-        eq(schema.submission.problemId, id),
-        inArray(schema.submission.result, [JudgeStatus.ACCEPTED, JudgeStatus.AST_CHECK_FAILED]),
-      ),
-    )
-  if (!mine?.value) return success(c, "0")
-  // 「近两年」按东八区日历算到当天零点
-  const since = dayStart(shiftMonthsByCalendar(new Date(), -24))
-  const [active, accepted] = await Promise.all([
-    db
-      .select({ value: count() })
-      .from(schema.user)
-      .where(and(eq(schema.user.isDisabled, false), gte(schema.user.lastLogin, since))),
-    db
-      .select({ value: countDistinct(schema.submission.userId) })
-      .from(schema.submission)
-      .where(
-        and(
-          eq(schema.submission.problemId, id),
-          inArray(schema.submission.result, [0, 10]),
-          gte(schema.submission.createTime, since),
-        ),
-      ),
-  ])
-  const total = active[0]?.value ?? 0
-  const solved = accepted[0]?.value ?? 0
-  return success(
-    c,
-    total > 0 && solved < total ? (((total - solved) / total) * 100).toFixed(2) : "0",
-  )
-})
-
 problemRoutes.get("/problems/:displayId/similar", optionalAuth, async (c) => {
   const [target] = await db
     .select({ id: schema.problem.id })
@@ -360,48 +310,6 @@ problemRoutes.get("/problems/:displayId/similar", optionalAuth, async (c) => {
   )
 })
 
-problemRoutes.get("/problems/:displayId/yearly-ac", async (c) => {
-  const [problem] = await db
-    .select({ id: schema.problem.id })
-    .from(schema.problem)
-    .where(
-      and(
-        sql`lower(${schema.problem.displayId}) = lower(${c.req.param("displayId")})`,
-        isNull(schema.problem.contestId),
-        eq(schema.problem.visible, true),
-      ),
-    )
-    .limit(1)
-  if (!problem) return failure(c, 404, "problem-not-found", "Problem does not exist")
-  const year = sql<number>`extract(year from ${localTime(schema.submission.createTime)})::int`
-  const rows = await db
-    .select({
-      year,
-      total: count(),
-      accepted: sql<number>`count(*) filter (where ${schema.submission.result} in (0, 10))::int`,
-    })
-    .from(schema.submission)
-    .where(
-      and(
-        eq(schema.submission.problemId, problem.id),
-        isNull(schema.submission.contestId),
-        notInArray(schema.submission.result, [6, 7]),
-      ),
-    )
-    .groupBy(year)
-    .orderBy(year)
-  return success(
-    c,
-    rows.map(
-      (row) =>
-        ({
-          ...row,
-          acRate: row.total > 0 ? Math.round((row.accepted / row.total) * 10_000) / 100 : 0,
-        }) satisfies YearlyAc,
-    ),
-  )
-})
-
 problemRoutes.get("/problems/:displayId", optionalAuth, async (c) => {
   const [row] = await db
     .select({
diff --git a/apps/web/src/oj/api.ts b/apps/web/src/oj/api.ts
index ca85995..50f0f1c 100644
--- a/apps/web/src/oj/api.ts
+++ b/apps/web/src/oj/api.ts
@@ -22,7 +22,7 @@ import {
   type CreateSubmissionResponse,
   type ProblemAuthor,
   type ProblemListItem,
-  type YearlyAc,
+  type ProblemStats,
   type ProblemList,
   type CreateFlowchartResponse,
   type FlowchartScores,
@@ -115,9 +115,14 @@ export async function getProblem(problemID: string, contestID: string) {
   return problem
 }
 
-// 未登录返回 "0"，登录后返回百分比字符串
-export function getProblemBeatRate(problemID: number) {
-  return api.get<string>(`problems/${problemID}/beat-count`)
+/**
+ * 题目页「统计」页签。problemID 是内部题号（problem.id），比赛题也能查。
+ * className 只有老师用：看哪个班的明细，不填就是最近做过这题的班
+ */
+export function getProblemStats(problemID: number, className?: string) {
+  return api.get<ProblemStats>(`problems/${problemID}/stats`, {
+    params: className ? { className } : {},
+  })
 }
 
 export async function getSubmission(id: string): Promise<Submission> {
@@ -405,12 +410,6 @@ export function getSimilarProblems(problemId: string) {
     .then((response) => response.map(toProblemRow))
 }
 
-export type { YearlyAc as YearlyACData } from "@oj2/contract"
-
-export function getProblemYearlyAC(problemId: string) {
-  return api.get<YearlyAc[]>(`problems/${encodeURIComponent(problemId)}/yearly-ac`)
-}
-
 // ==================== 流程图相关API ====================
 
 export function submitFlowchart(data: {
diff --git a/apps/web/src/oj/problem/components/ProblemDrawer.vue b/apps/web/src/oj/problem/components/ProblemDrawer.vue
index d1620af..3f73bba 100644
--- a/apps/web/src/oj/problem/components/ProblemDrawer.vue
+++ b/apps/web/src/oj/problem/components/ProblemDrawer.vue
@@ -142,7 +142,7 @@ function goAllSubmissions() {
           </button>
         </div>
       </template>
-      <ProblemInfo v-if="lastOpened === 'info'" />
+      <ProblemInfo v-if="lastOpened === 'info'" @open-submissions="open = 'submission'" />
       <ProblemReaction v-else-if="lastOpened === 'reaction'" />
       <template v-else>
         <ProblemSubmission />
diff --git a/apps/web/src/oj/problem/components/ProblemInfo.vue b/apps/web/src/oj/problem/components/ProblemInfo.vue
index 1c13e17..6f9acbc 100644
--- a/apps/web/src/oj/problem/components/ProblemInfo.vue
+++ b/apps/web/src/oj/problem/components/ProblemInfo.vue
@@ -1,164 +1,716 @@
 <script setup lang="ts">
 import { Icon } from "@iconify/vue"
+import { useThemeVars } from "naive-ui"
 import { storeToRefs } from "pinia"
+import { getProblemStats } from "oj/api"
+import { useContestStore } from "oj/store/contest"
 import { useProblemStore } from "oj/store/problem"
+import { useTone, type Tone } from "oj/submission/composables/tone"
+import { classLabel } from "oj/submission/utils"
 import { DIFFICULTY, JUDGE_STATUS } from "utils/constants"
-import type { SUBMISSION_RESULT } from "utils/types"
-import { getACRateNumber, getTagColor, parseTime } from "utils/functions"
-import { Pie } from "vue-chartjs"
-import { Chart as ChartJS, ArcElement, Title, Tooltip, Legend, Colors } from "chart.js"
-import { getProblemBeatRate } from "oj/api"
-import { getProblemYearlyAC, type YearlyACData } from "oj/api"
-import ProblemYearlyChart from "./ProblemYearlyChart.vue"
-import { useBreakpoints } from "shared/composables/breakpoints"
+import { getTagColor, parseTime } from "utils/functions"
+import type { ProblemStats, SUBMISSION_RESULT } from "utils/types"
+import { useProblemPageContext } from "../composables/problemPageContext"
 
-// 仅注册饼图所需的 Chart.js 组件
-ChartJS.register(ArcElement, Title, Tooltip, Legend, Colors)
+/**
+ * 「统计」页签（设计稿「题目页统计重设计」：学生 A、老师 B）。
+ *
+ * 学生看的是「这题难不难 → 大家几次做对 → 常错在哪 → 你们班」，全部按人算；自己卡住了
+ * 再多一张卡。老师看的是一个班：谁做对了、谁交了没对（卡在哪）、谁还没交 —— 原来工具栏上
+ * 的「课堂统计」并进了这里。原来的描述表、击败用户、饼图、历年 AC 率都去掉了。
+ */
+const emit = defineEmits<{ openSubmissions: [] }>()
 
-const problemStore = useProblemStore()
-const { problem } = storeToRefs(problemStore)
+const { problem } = storeToRefs(useProblemStore())
+const contestStore = useContestStore()
+const ctx = useProblemPageContext()
+const route = useRoute()
+const router = useRouter()
+const theme = useThemeVars()
+const tone = useTone()
 
-const { isDesktop } = useBreakpoints()
+const stats = ref<ProblemStats | null>(null)
+const failed = ref(false)
+const className = ref<string | null>(null)
 
-const beatRate = ref("0")
-const yearlyACData = ref<YearlyACData[]>([])
-
-const data = computed(() => {
-  // statisticInfo 是 { 判题状态码: 次数 } 的 JSONB，契约里是 Record<string, unknown>
-  const status = problem.value!.statisticInfo as Record<string, number>
-  const labels: string[] = []
-  const values: number[] = []
-  for (const code in status) {
-    if (status[code] !== 0) {
-      labels.push(JUDGE_STATUS[Number(code) as SUBMISSION_RESULT].name)
-      values.push(status[code]!)
-    }
+async function load() {
+  if (!problem.value) return
+  failed.value = false
+  try {
+    const res = await getProblemStats(problem.value.id, className.value ?? undefined)
+    stats.value = res
+    if (res.classDetail) className.value = res.classDetail.className
+  } catch {
+    failed.value = true
   }
-  return {
-    labels,
-    datasets: [{ data: values, hoverOffset: 5, borderRadius: 10 }],
+}
+
+onMounted(load)
+
+function changeClass(value: string) {
+  className.value = value
+  load()
+}
+
+const teacherView = computed(() => stats.value?.classes != null)
+
+function resultName(result: number) {
+  return JUDGE_STATUS[result as SUBMISSION_RESULT]?.name ?? "其他"
+}
+
+function resultTone(result: number): Tone {
+  return JUDGE_STATUS[result as SUBMISSION_RESULT]?.type ?? "default"
+}
+
+/** 条的颜色：运行时错误橙、答案错误红、编译失败灰 —— 和提交列表的胶囊一个配色 */
+function barColor(result: number) {
+  const kind = resultTone(result)
+  // 编译失败用灰：它和运行时错误都是 warning，都画成橙色就分不开了
+  if (result === -2 || kind === "default" || kind === "info") return theme.value.textColor3
+  return tone(kind).color
+}
+
+// ---------- 学生 ----------
+
+const verdict = computed(() => {
+  const s = stats.value
+  if (!s || !s.tried) return null
+  const rate = s.solved / s.tried
+  const firstShare = s.solved ? s.tries.one / s.solved : 0
+  const manyShare = s.solved ? s.tries.many / s.solved : 0
+  const detail = `${s.tried} 人做过，${s.solved} 人做对了`
+  if (rate >= 0.9 && firstShare >= 0.6) {
+    return { kind: "success" as const, text: "这题不难：大多数人第一次交就对了", detail }
   }
+  if (problem.value?.difficulty === "Low" && (rate < 0.9 || manyShare >= 0.15)) {
+    return { kind: "warning" as const, text: "标的是「简单」，但不少人卡住了", detail }
+  }
+  if (rate >= 0.75) {
+    return { kind: "info" as const, text: "多数人做对了，不少人要多试几次", detail }
+  }
+  return { kind: "warning" as const, text: "这题有点难：不少人还没做对", detail }
 })
 
-const numbers = computed(() => {
+const triesSegments = computed(() => {
+  const s = stats.value
+  if (!s) return []
+  const green = theme.value.successColor
   return [
+    { key: "one", label: "1 次", value: s.tries.one, color: green, opacity: 1 },
+    { key: "few", label: "2–3 次", value: s.tries.few, color: green, opacity: 0.6 },
+    { key: "many", label: "4 次以上", value: s.tries.many, color: green, opacity: 0.3 },
     {
-      icon: "streamline-ultimate-color:checklist",
-      title: problem.value?.submissionNumber ?? 0,
-      content: "总提交",
-      int: true,
-      suffix: "",
-    },
-    {
-      icon: "streamline-emojis:woman-raising-hand-2",
-      title: problem.value?.acceptedNumber ?? 0,
-      content: "通过数",
-      int: true,
-      suffix: "",
-    },
-    {
-      icon: "fluent-emoji:chart-increasing",
-      title: getACRateNumber(
-        problem.value?.acceptedNumber ?? 0,
-        problem.value?.submissionNumber ?? 0,
-      ),
-      content: "通过率",
-      int: false,
-      suffix: "%",
-    },
-    {
-      icon: "streamline-emojis:sparkles",
-      title: parseFloat(beatRate.value),
-      content: "击败用户",
-      int: false,
-      suffix: "%",
+      key: "none",
+      label: "没做对",
+      value: s.tried - s.solved,
+      color: theme.value.dividerColor,
+      opacity: 1,
     },
   ]
 })
 
-const options = {
-  plugins: {
-    title: { text: "提交结果的比例", display: true, font: { size: 20 } },
-  },
-}
+const failedTotal = computed(() =>
+  (stats.value?.failures ?? []).reduce((sum, item) => sum + item.count, 0),
+)
+const topFailures = computed(() => (stats.value?.failures ?? []).slice(0, 3))
 
-async function getBeatRate() {
-  const res = await getProblemBeatRate(problem.value!.id)
-  beatRate.value = res
-}
-
-async function getYearlyAC() {
-  const res = await getProblemYearlyAC(problem.value!._id)
-  yearlyACData.value = res
-}
-
-onMounted(() => {
-  getBeatRate()
-  getYearlyAC()
+/** 错得最多的那一种，给一句该怎么办。都指向「运行例子」：提交前自己就能看出来 */
+const tip = computed(() => {
+  const s = stats.value
+  const top = s?.failures[0]
+  if (!s || !top) return ""
+  if (top.result === -1) {
+    return s.wrongAnswerFirstCase >= top.count * 0.6
+      ? "答案错误几乎都卡在第 1 个测试点：多半是例子都没对上。先点「运行例子」，把你的输出和例子一行一行对一对。"
+      : "答案错误最多：输出和标准答案对不上。留意空格、换行和标点，交之前先点「运行例子」对一对。"
+  }
+  if (top.result === 4) {
+    return "运行时错误最多：程序跑到一半出错了。交之前先点「运行例子」，看看有没有红色的报错。"
+  }
+  if (top.result === -2) {
+    return "编译失败最多：代码有语法错误，程序根本没跑起来。交之前先点「运行例子」检查一下。"
+  }
+  return ""
 })
+
+/** 自己交了好几次还没对：比赛里没有举手，也不提「看别人」 */
+const stuck = computed(() => {
+  const me = stats.value?.me
+  return me && !me.solved && me.attempts >= 3 ? me.attempts : 0
+})
+
+// ---------- 老师 ----------
+
+const detail = computed(() => stats.value?.classDetail ?? null)
+
+const classOptions = computed(() =>
+  (stats.value?.classes ?? []).map((item) => ({
+    label: `${classLabel(item.className)} · ${item.solved}/${item.tried}`,
+    value: item.className,
+  })),
+)
+
+const classSegments = computed(() => {
+  const d = detail.value
+  if (!d) return []
+  return [
+    { key: "solved", label: "做对", value: d.solved.length, color: theme.value.successColor },
+    { key: "unsolved", label: "交了没对", value: d.unsolved.length, color: theme.value.errorColor },
+    { key: "untouched", label: "没交", value: d.untouched.length, color: theme.value.dividerColor },
+  ]
+})
+
+const classFailedTotal = computed(() =>
+  (detail.value?.failures ?? []).reduce((sum, item) => sum + item.count, 0),
+)
+
+/** 这个班错得最多的和全站不一样时点出来：老师该看的就是这种差别 */
+const siteDiffers = computed(() => {
+  const site = stats.value?.failures[0]
+  const mine = detail.value?.failures[0]
+  return site && mine && site.result !== mine.result ? resultName(site.result) : ""
+})
+
+const showSolved = ref(false)
+const showUntouched = ref(false)
+
+function openStatistics() {
+  const href = router.resolve({
+    name: "statistics",
+    query: { problem: problem.value!._id, className: className.value ?? "", period: "all" },
+  }).href
+  window.open(href, "_blank")
+}
+
+function openClassSubmissions() {
+  const href = router.resolve({
+    name: "submissions",
+    query: { problem: problem.value!._id, className: className.value ?? "" },
+  }).href
+  window.open(href, "_blank")
+}
+
+/** 「2025-12-05」→「2025年12月5日」。后端给的已经是东八区的日子，不用再换算 */
+function dayText(day: string) {
+  const [year, month, date] = day.split("-").map(Number)
+  return `${year}年${month}月${date}日`
+}
+
+function segmentWidth(value: number, total: number) {
+  return total ? `${(value / total) * 100}%` : "0"
+}
 </script>
 
 <template>
-  <n-descriptions bordered label-placement="left" :column="isDesktop ? 3 : 1" v-if="problem">
-    <n-descriptions-item label="编号">
-      {{ problem._id }}
-    </n-descriptions-item>
-    <n-descriptions-item label="出题人">
-      {{ problem.createdBy.username }}
-    </n-descriptions-item>
-    <n-descriptions-item label="创建时间">
-      {{ parseTime(problem.createTime) }}
-    </n-descriptions-item>
-    <!-- 比赛进行中，难度不下发（difficulty 为 null），这一项整个不显示 -->
-    <n-descriptions-item v-if="problem.difficulty" label="难度">
-      <n-tag :type="getTagColor(problem.difficulty)">
+  <div v-if="problem" class="info">
+    <!-- 原来占一大块的描述表收成一行 -->
+    <div class="meta">
+      <b class="meta-title">{{ problem._id }} {{ problem.title }}</b>
+      <!-- 比赛进行中难度不下发（null），整个不显示 -->
+      <n-tag
+        v-if="problem.difficulty"
+        size="small"
+        round
+        :bordered="false"
+        :type="getTagColor(problem.difficulty)"
+      >
         {{ DIFFICULTY[problem.difficulty] }}
       </n-tag>
-    </n-descriptions-item>
-    <n-descriptions-item :span="2" label="标签">
-      <n-flex>
-        <n-tag type="info" v-for="tag in problem.tags" :key="tag">
-          {{ tag }}
-        </n-tag>
-      </n-flex>
-    </n-descriptions-item>
-  </n-descriptions>
-  <n-grid :cols="isDesktop ? 4 : 2" :x-gap="10" :y-gap="10" class="cards">
-    <n-gi v-for="item in numbers" :key="item.content">
-      <n-card hoverable>
-        <n-flex vertical align="center">
-          <Icon v-if="isDesktop" :icon="item.icon" width="40" />
-          <n-h2 class="number">
-            <n-number-animation :to="item.title" :precision="item.int ? 0 : 2" />
-            <span v-if="item.suffix">{{ item.suffix }}</span>
-          </n-h2>
-          <n-h4 class="number-label">{{ item.content }}</n-h4>
-        </n-flex>
-      </n-card>
-    </n-gi>
-  </n-grid>
-  <div class="pie" v-if="problem && problem.submissionNumber > 0">
-    <Pie :data="data" :options="options" />
+      <n-tag
+        v-for="tag in problem.tags"
+        :key="tag"
+        size="small"
+        round
+        :bordered="false"
+        type="info"
+      >
+        {{ tag }}
+      </n-tag>
+      <span class="spacer"></span>
+      <n-text depth="3" class="meta-author">{{ problem.createdBy.username }} 出题</n-text>
+    </div>
+
+    <n-text v-if="failed" type="error">统计没拉下来，关掉再打开试试</n-text>
+    <div v-else-if="!stats" class="center"><n-spin size="small" /></div>
+
+    <!-- 比赛进行中：别人的情况等比赛结束再公布 -->
+    <div v-else-if="stats.locked" class="empty">
+      <span class="empty-icon"><Icon icon="ph:lock-simple" :width="18" /></span>
+      <b>比赛结束后才能看到大家的情况</b>
+      <n-text depth="3">
+        <template v-if="contestStore.contest">
+          比赛 {{ parseTime(contestStore.contest.endTime, "HH:mm") }} 结束。
+        </template>
+        现在只看得到你自己的提交，别人几次做对、错在哪，结束后一起公布。
+      </n-text>
+      <router-link
+        :to="{ name: 'contest rank', params: { contestID: route.params.contestID } }"
+        class="link"
+      >
+        去看比赛排名 ›
+      </router-link>
+    </div>
+
+    <!-- ==================== 老师：看一个班 ==================== -->
+    <template v-else-if="teacherView">
+      <div v-if="!detail" class="empty">
+        <span class="empty-icon"><Icon icon="ph:users" :width="18" /></span>
+        <b>还没有班级做过这道题</b>
+        <n-text depth="3">布置到这节课之后，这里会按班显示谁做对了、谁还没交。</n-text>
+        <n-button type="primary" secondary @click="router.push('/classroom')">
+          去课堂看板布置 →
+        </n-button>
+      </div>
+      <template v-else>
+        <div class="class-head">
+          <n-select
+            :value="className"
+            :options="classOptions"
+            size="small"
+            class="class-select"
+            :consistent-menu-width="false"
+            @update:value="changeClass"
+          />
+          <n-text depth="3" class="small">{{ dayText(detail.day) }}做的</n-text>
+          <span class="spacer"></span>
+          <a href="#" class="link small" @click.prevent="openStatistics">
+            在数据统计里看 <Icon icon="ph:arrow-square-out" :width="13" />
+          </a>
+        </div>
+
+        <div class="bar">
+          <span
+            v-for="seg in classSegments"
+            :key="seg.key"
+            :style="{ width: segmentWidth(seg.value, detail.roster), background: seg.color }"
+          ></span>
+        </div>
+        <div class="legend">
+          <span v-for="seg in classSegments" :key="seg.key">
+            <i :style="{ background: seg.color }"></i>{{ seg.label }} <b>{{ seg.value }}</b>
+          </span>
+        </div>
+
+        <div v-if="classFailedTotal" class="line">
+          <b>没通过的 {{ classFailedTotal }} 次：</b>
+          <n-text depth="2">
+            {{
+              detail.failures
+                .slice(0, 3)
+                .map((item) => `${resultName(item.result)} ${item.count}`)
+                .join(" · ")
+            }}
+          </n-text>
+          <span class="spacer"></span>
+          <n-text v-if="siteDiffers" depth="3" class="small">全站是{{ siteDiffers }}最多</n-text>
+        </div>
+
+        <template v-if="detail.unsolved.length">
+          <div class="line">
+            <b>交了没对（{{ detail.unsolved.length }} 人）</b>
+            <span class="spacer"></span>
+            <n-text depth="3" class="small">次数多的在前</n-text>
+          </div>
+          <div class="people">
+            <div v-for="(item, index) in detail.unsolved" :key="index" class="person">
+              <b>{{ item.realName }}</b>
+              <n-text depth="3">{{ item.attempts }} 次</n-text>
+              <span :style="{ color: barColor(item.lastResult) }">
+                {{ resultName(item.lastResult) }}
+              </span>
+            </div>
+          </div>
+        </template>
+
+        <div v-if="detail.solved.length" class="fold">
+          <div class="fold-head" @click="showSolved = !showSolved">
+            <b>做对 {{ detail.solved.length }}</b>
+            <span class="fold-names">
+              {{ showSolved ? "" : detail.solved.join("、") }}
+            </span>
+            <span class="link small">{{ showSolved ? "收起" : "展开" }}</span>
+          </div>
+          <div v-if="showSolved" class="fold-body">{{ detail.solved.join("、") }}</div>
+        </div>
+        <div v-if="detail.untouched.length" class="fold">
+          <div class="fold-head" @click="showUntouched = !showUntouched">
+            <b>没交 {{ detail.untouched.length }}</b>
+            <span class="fold-names">{{ showUntouched ? "" : "展开看名单" }}</span>
+            <span class="link small">{{ showUntouched ? "收起" : "展开" }}</span>
+          </div>
+          <div v-if="showUntouched" class="fold-body">{{ detail.untouched.join("、") }}</div>
+        </div>
+
+        <div class="foot">
+          <a href="#" class="link small" @click.prevent="openClassSubmissions">
+            看这个班这道题的提交 ›
+          </a>
+        </div>
+      </template>
+    </template>
+
+    <!-- ==================== 学生 ==================== -->
+    <div v-else-if="!stats.tried" class="empty">
+      <span class="empty-icon"><Icon icon="ph:sparkle" :width="18" /></span>
+      <b>还没有人交过这道题</b>
+      <n-text depth="3">你可以做第一个。</n-text>
+    </div>
+    <template v-else>
+      <div
+        v-if="verdict"
+        class="verdict"
+        :style="{
+          background: tone(verdict.kind).background,
+          borderColor: tone(verdict.kind).background,
+        }"
+      >
+        <b :style="{ color: tone(verdict.kind).color }">
+          <Icon icon="ph:gauge" :width="16" />{{ verdict.text }}
+        </b>
+        <n-text depth="2" class="small">{{ verdict.detail }}</n-text>
+      </div>
+
+      <div v-if="stats.solved" class="section">
+        <div class="line">
+          <b>做对用了几次</b>
+          <span class="spacer"></span>
+          <n-text depth="3" class="small">按人算</n-text>
+        </div>
+        <div class="bar">
+          <span
+            v-for="seg in triesSegments"
+            :key="seg.key"
+            :style="{
+              width: segmentWidth(seg.value, stats.tried),
+              background: seg.color,
+              opacity: seg.opacity,
+            }"
+          ></span>
+        </div>
+        <div class="legend">
+          <span v-for="seg in triesSegments" :key="seg.key">
+            <i :style="{ background: seg.color, opacity: seg.opacity }"></i>{{ seg.label }}
+            <b>{{ seg.value }}</b>
+          </span>
+        </div>
+      </div>
+
+      <div v-if="topFailures.length" class="section">
+        <b>没通过的 {{ failedTotal }} 次，错在哪</b>
+        <div v-for="item in topFailures" :key="item.result" class="fail">
+          <span class="fail-name">{{ resultName(item.result) }}</span>
+          <span class="fail-track">
+            <span
+              :style="{
+                width: segmentWidth(item.count, topFailures[0]!.count),
+                background: barColor(item.result),
+              }"
+            ></span>
+          </span>
+          <span class="fail-count">{{ item.count }} 次</span>
+        </div>
+        <div
+          v-if="tip"
+          class="tip"
+          :style="{ background: tone('warning').background, color: tone('warning').color }"
+        >
+          <Icon icon="ph:lightbulb" :width="15" class="tip-icon" />
+          <span>{{ tip }}</span>
+        </div>
+      </div>
+
+      <div v-if="stats.myClass?.tried" class="class-box">
+        <div class="line">
+          <b>你们班 · {{ classLabel(stats.myClass.className) }}</b>
+          <span class="spacer"></span>
+          <span>
+            <b class="big">{{ stats.myClass.solved }}</b>
+            <n-text depth="3"> / {{ stats.myClass.tried }} 人做对</n-text>
+          </span>
+        </div>
+        <div class="bar thin">
+          <span
+            :style="{
+              width: segmentWidth(stats.myClass.solved, stats.myClass.tried),
+              background: theme.successColor,
+            }"
+          ></span>
+        </div>
+      </div>
+
+      <div
+        v-if="stuck && ctx.entry !== 'contest'"
+        class="stuck"
+        :style="{ borderColor: tone('warning').background, background: tone('warning').background }"
+      >
+        <b>你交了 {{ stuck }} 次，还没对上</b>
+        <n-text depth="2" class="small">
+          卡了这么久，可以点右上角「举手求助」问老师；也可以去「我的提交」看看每一次错在哪。
+        </n-text>
+        <div>
+          <n-button size="small" @click="emit('openSubmissions')">看我的提交</n-button>
+        </div>
+      </div>
+    </template>
   </div>
-  <ProblemYearlyChart :data="yearlyACData" />
 </template>
+
 <style scoped>
-.cards {
-  margin-top: 24px;
+.info {
+  display: flex;
+  flex-direction: column;
+  gap: 14px;
+  font-size: 14px;
 }
 
-.number {
-  margin: 0;
-  font-weight: bold;
+.meta {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+  flex-wrap: wrap;
 }
 
-.number-label {
-  margin: 0;
+.meta-title {
+  margin-right: 4px;
 }
 
-.pie {
-  width: 100%;
-  max-width: 500px;
-  margin: 24px auto;
+.meta-author,
+.small {
+  font-size: 13px;
+}
+
+.spacer {
+  flex: 1 1 0;
+}
+
+.center {
+  display: flex;
+  justify-content: center;
+  padding: 40px 0;
+}
+
+.empty {
+  padding: 60px 16px;
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  gap: 8px;
+  text-align: center;
+}
+
+.empty-icon {
+  width: 40px;
+  height: 40px;
+  border-radius: 50%;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  background: v-bind("theme.actionColor");
+  color: v-bind("theme.textColor2");
+  margin-bottom: 4px;
+}
+
+.link {
+  color: v-bind("theme.primaryColor");
+  text-decoration: none;
+  display: inline-flex;
+  align-items: center;
+  gap: 3px;
+  cursor: pointer;
+}
+
+.verdict {
+  padding: 12px 14px;
+  border-radius: 8px;
+  border: 1px solid;
+  display: flex;
+  flex-direction: column;
+  gap: 4px;
+}
+
+.verdict b {
+  font-size: 16px;
+  display: flex;
+  align-items: center;
+  gap: 6px;
+}
+
+.section {
+  display: flex;
+  flex-direction: column;
+  gap: 8px;
+}
+
+.line {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+  flex-wrap: wrap;
+}
+
+.bar {
+  height: 12px;
+  border-radius: 3px;
+  overflow: hidden;
+  display: flex;
+  gap: 2px;
+  background: v-bind("theme.dividerColor");
+}
+
+.bar.thin {
+  height: 8px;
+}
+
+.bar > span {
+  height: 100%;
+}
+
+.legend {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 4px 16px;
+  font-size: 13px;
+  color: v-bind("theme.textColor2");
+}
+
+.legend i {
+  display: inline-block;
+  width: 10px;
+  height: 10px;
+  border-radius: 2px;
+  margin-right: 5px;
+  vertical-align: -1px;
+}
+
+.fail {
+  display: flex;
+  align-items: center;
+  gap: 12px;
+  font-size: 13px;
+}
+
+.fail-name {
+  width: 72px;
+  flex: none;
+}
+
+.fail-track {
+  flex: 1;
+  height: 10px;
+  border-radius: 5px;
+  background: v-bind("theme.actionColor");
+  overflow: hidden;
+}
+
+.fail-track > span {
+  display: block;
+  height: 100%;
+  border-radius: 5px;
+}
+
+.fail-count {
+  width: 48px;
+  flex: none;
+  text-align: right;
+  font-variant-numeric: tabular-nums;
+}
+
+.tip {
+  display: flex;
+  gap: 8px;
+  padding: 10px 12px;
+  border-radius: 6px;
+  font-size: 13px;
+  line-height: 1.6;
+}
+
+.tip-icon {
+  flex: none;
+  margin-top: 3px;
+}
+
+.class-box {
+  padding: 12px 14px;
+  border-radius: 8px;
+  border: 1px solid v-bind("theme.dividerColor");
+  display: flex;
+  flex-direction: column;
+  gap: 8px;
+}
+
+.big {
+  font-size: 18px;
+  color: v-bind("theme.successColor");
+}
+
+.stuck {
+  padding: 12px 14px;
+  border-radius: 8px;
+  border: 1px solid;
+  display: flex;
+  flex-direction: column;
+  gap: 6px;
+}
+
+.class-head {
+  display: flex;
+  align-items: center;
+  gap: 10px;
+}
+
+.class-select {
+  width: 190px;
+}
+
+.people {
+  display: grid;
+  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
+  gap: 6px;
+}
+
+.person {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+  padding: 5px 10px;
+  border-radius: 6px;
+  border: 1px solid v-bind("theme.dividerColor");
+  font-size: 13px;
+  white-space: nowrap;
+  overflow: hidden;
+}
+
+.fold {
+  border-radius: 6px;
+  background: v-bind("theme.actionColor");
+  font-size: 13px;
+}
+
+.fold-head {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  padding: 8px 12px;
+  cursor: pointer;
+}
+
+.fold-names {
+  flex: 1;
+  min-width: 0;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+  color: v-bind("theme.textColor2");
+}
+
+.fold-body {
+  padding: 0 12px 10px;
+  line-height: 1.8;
+  color: v-bind("theme.textColor2");
+}
+
+.foot {
+  display: flex;
+  justify-content: flex-end;
 }
 </style>
diff --git a/apps/web/src/oj/problem/components/ProblemYearlyChart.vue b/apps/web/src/oj/problem/components/ProblemYearlyChart.vue
deleted file mode 100644
index c85dc19..0000000
--- a/apps/web/src/oj/problem/components/ProblemYearlyChart.vue
+++ /dev/null
@@ -1,77 +0,0 @@
-<template>
-  <div class="yearly-chart" v-if="props.data.length > 1">
-    <Line :data="chartData" :options="chartOptions" />
-  </div>
-</template>
-
-<script setup lang="ts">
-import { Line } from "vue-chartjs"
-import {
-  Chart as ChartJS,
-  CategoryScale,
-  Filler,
-  LinearScale,
-  LineElement,
-  PointElement,
-  Title,
-  Tooltip,
-} from "chart.js"
-import type { YearlyACData } from "oj/api"
-
-ChartJS.register(CategoryScale, Filler, LinearScale, LineElement, PointElement, Title, Tooltip)
-
-const props = defineProps<{ data: YearlyACData[] }>()
-
-const chartData = computed(() => ({
-  labels: props.data.map((d) => String(d.year)),
-  datasets: [
-    {
-      label: "AC 率",
-      data: props.data.map((d) => d.acRate),
-      fill: true,
-      tension: 0.3,
-      backgroundColor: "rgba(99, 179, 237, 0.2)",
-      borderColor: "rgba(99, 179, 237, 1)",
-      pointBackgroundColor: "rgba(99, 179, 237, 1)",
-    },
-  ],
-}))
-
-const chartOptions = computed(() => ({
-  responsive: true,
-  maintainAspectRatio: false,
-  plugins: {
-    title: {
-      display: true,
-      text: "历年 AC 率",
-      font: { size: 20 },
-    },
-    tooltip: {
-      callbacks: {
-        label: (context: any) => {
-          const d = props.data[context.dataIndex]
-          return [`AC 率: ${d.acRate}%`, `通过: ${d.accepted} / ${d.total}`]
-        },
-      },
-    },
-  },
-  scales: {
-    y: {
-      min: 0,
-      max: 100,
-      ticks: {
-        callback: (value: any) => `${value}%`,
-      },
-    },
-  },
-}))
-</script>
-
-<style scoped>
-.yearly-chart {
-  width: 100%;
-  max-width: 500px;
-  height: 250px;
-  margin: 24px auto;
-}
-</style>
diff --git a/apps/web/src/oj/problem/composables/problemPageContext.ts b/apps/web/src/oj/problem/composables/problemPageContext.ts
index 8a7f2eb..817b5fa 100644
--- a/apps/web/src/oj/problem/composables/problemPageContext.ts
+++ b/apps/web/src/oj/problem/composables/problemPageContext.ts
@@ -39,8 +39,9 @@ interface EntryRules {
    */
   collab: boolean
   /**
-   * 教师的「课堂统计」。统计接口按 displayId 在公开题库里找题（`submission-statistics.ts`），
-   * 比赛题号拿过去查到的是另一道公开题，或者 404
+   * 工具栏上教师的「课堂统计」（新标签开数据统计页）。题库入口已经并进「统计」页签的老师
+   * 视图（按班看谁没做对，带「在数据统计里看」），只剩没有抽屉的题单入口还要这个按钮。
+   * 比赛不给：统计接口按 displayId 在公开题库里找题，比赛题号查到的是另一道公开题，或者 404
    */
   classStats: boolean
   /**
@@ -60,7 +61,7 @@ const RULES: Record<ProblemEntry, EntryRules> = {
     backToProblemSet: false,
     help: true,
     collab: true,
-    classStats: true,
+    classStats: false,
     allSubmissionsInMenu: false,
   },
   // 题单里什么「以前的」都不给看：加入题单之前的提交、统计、点评都能拿来抄答案
diff --git a/apps/web/src/utils/types.ts b/apps/web/src/utils/types.ts
index b099df8..7010a4a 100644
--- a/apps/web/src/utils/types.ts
+++ b/apps/web/src/utils/types.ts
@@ -81,6 +81,7 @@ export type ProblemStatus = "passed" | "failed" | "not_test"
  * shared/api.ts 原来还得用 `Tag & { problemCount: number }` 把它补回来。
  */
 export type { Tag, TagCategory } from "@oj2/contract"
+export type { ProblemStats, ProblemClassDetail } from "@oj2/contract"
 
 export type {
   AdminTag,
diff --git a/packages/contract/src/problem.ts b/packages/contract/src/problem.ts
index c391c0e..1487eb3 100644
--- a/packages/contract/src/problem.ts
+++ b/packages/contract/src/problem.ts
@@ -1,6 +1,7 @@
 import { z } from "zod"
 
 import { paginatedSchema, sampleUserSchema } from "./common"
+import { judgeStatusSchema } from "./judge-status"
 import { problemLanguageSchema } from "./language"
 
 /**
@@ -446,11 +447,64 @@ export const problemAuthorSchema = z.object({
   problemCount: z.number().int().nonnegative(),
 })
 
-export const yearlyAcSchema = z.object({
-  year: z.number().int(),
-  total: z.number().int().nonnegative(),
-  accepted: z.number().int().nonnegative(),
-  acRate: z.number(),
+const failureCountSchema = z.object({ result: judgeStatusSchema, count: z.number().int() })
+
+/** 老师选中一个班时的明细：谁做对了、谁交了没对（卡在哪）、谁还没交 */
+export const problemClassDetailSchema = z.object({
+  className: z.string(),
+  /** 班里的学生数（学生角色、没禁用） */
+  roster: z.number().int(),
+  /** 这个班一起做这道题的那天（东八区 YYYY-MM-DD，交的人最多的那天）—— 「2025年12月5日做的」 */
+  day: z.string(),
+  failures: z.array(failureCountSchema),
+  /** 交了没对，次数多的在前。名字是剥掉 ks<班级号> 前缀的那一段 */
+  unsolved: z.array(
+    z.object({ realName: z.string(), attempts: z.number().int(), lastResult: judgeStatusSchema }),
+  ),
+  solved: z.array(z.string()),
+  /** 班里还没交过的 */
+  untouched: z.array(z.string()),
+})
+
+/**
+ * 题目页「统计」页签。全部**按人**算，不按提交条数 —— 原来的「通过数」是 AC 条数
+ * （3092 是 219 条、202 个人），「通过率」是按提交算的，学生看了不知道这题难不难。
+ * 原来的「击败用户」（分母是近两年所有登录过的人）、饼图、历年 AC 率一起去掉了。
+ */
+export const problemStatsSchema = z.object({
+  /** 比赛还没结束（又不是比赛管理员）：别人的情况一律不给，下面的数字都是 0 / 空 */
+  locked: z.boolean(),
+  /** 交过的人 */
+  tried: z.number().int(),
+  solved: z.number().int(),
+  /** 做对的人用了几次：1 次 / 2–3 次 / 4 次以上 */
+  tries: z.object({ one: z.number().int(), few: z.number().int(), many: z.number().int() }),
+  /** 没通过的提交按结果分，多的在前（不含判题中） */
+  failures: z.array(failureCountSchema),
+  /** 答案错误里第 1 个测试点就没过的条数 —— 多半是例子都没对上，提示先点「运行例子」 */
+  wrongAnswerFirstCase: z.number().int(),
+  /** 我自己：交了几次、做对没有。没登录为 null */
+  me: z.object({ attempts: z.number().int(), solved: z.boolean() }).nullable(),
+  /** 学生自己班这题 x / y 人做对（y 是班里交过的人）。没班级、比赛里为 null */
+  myClass: z
+    .object({ className: z.string(), tried: z.number().int(), solved: z.number().int() })
+    .nullable(),
+  /**
+   * 老师：一起做过这题的班（同一天至少 5 个人交过 —— 零星几个人自己刷到、补做的不算），
+   * 按那天倒序。原来工具栏上的「课堂统计」并进了这里。学生、比赛里为 null
+   */
+  classes: z
+    .array(
+      z.object({
+        className: z.string(),
+        tried: z.number().int(),
+        solved: z.number().int(),
+        day: z.string(),
+      }),
+    )
+    .nullable(),
+  /** 老师选中的那个班（默认 classes 第一个）的明细 */
+  classDetail: problemClassDetailSchema.nullable(),
 })
 
 export type AstRuleEngine = z.infer<typeof astRuleEngineSchema>
@@ -468,4 +522,5 @@ export type SqlConfig = z.infer<typeof sqlConfigSchema>
 export type SqlDisplay = z.infer<typeof sqlDisplaySchema>
 export type SqlDisplayTable = z.infer<typeof sqlDisplayTableSchema>
 export type SqlDisplayColumn = z.infer<typeof sqlDisplayColumnSchema>
-export type YearlyAc = z.infer<typeof yearlyAcSchema>
+export type ProblemStats = z.infer<typeof problemStatsSchema>
+export type ProblemClassDetail = z.infer<typeof problemClassDetailSchema>