diff --git a/apps/web/src/oj/problem/components/ContextBar.vue b/apps/web/src/oj/problem/components/ContextBar.vue
new file mode 100644
index 0000000..2d6b29f
--- /dev/null
+++ b/apps/web/src/oj/problem/components/ContextBar.vue
@@ -0,0 +1,309 @@
+<script setup lang="ts">
+import { storeToRefs } from "pinia"
+import type { RouteLocationRaw } from "vue-router"
+import { getProblemSetDetail, getProblemSetProblems } from "oj/api"
+import { useContestStore } from "oj/store/contest"
+import { useLessonStore } from "oj/store/lesson"
+import { useProblemStore } from "oj/store/problem"
+import { useUserStore } from "shared/store/user"
+import type { ProblemSet, ProblemSetProblem } from "utils/types"
+import { useProblemPageContext } from "../composables/problemPageContext"
+import ProblemChips, { type ChipItem } from "./ProblemChips.vue"
+
+/**
+ * 左栏顶上的一条：「这道题是从哪来的」。按入口路由决定是哪一种，最多一条：
+ *
+ * - 课堂：这道题在「班里在做」的列表里 —— 做完几道 + 每道的题号 + 上一题 / 下一题
+ * - 题单：题单名 + 进度 + 第几题 + 上一题 / 下一题
+ * - 比赛：比赛名 + 每道的题号 + 还剩多久 + 排名
+ * - 都不是：不显示
+ *
+ * 一道题既在这节课里、又是从题单进来的，按入口显示题单条。
+ * 换题用的都是普通链接，通过之后欠着的那次强制点评由 SubmissionEffects 的路由守卫拦下。
+ */
+
+/** 题多于这个数就横向滚动、去掉 ‹ ›：一节课一般 5 道以内，按 5 道设计 */
+const CHIPS_FIT = 5
+
+const ctx = useProblemPageContext()
+const userStore = useUserStore()
+const { problem } = storeToRefs(useProblemStore())
+const currentId = computed(() => problem.value?._id ?? "")
+
+/** 刚在这一页上做出来（不是本来就做过）：换题时 id 跟着变，那一次不算 */
+function onSolvedHere(callback: () => void) {
+  watch(
+    () => [problem.value?.id, problem.value?.myStatus] as const,
+    ([id, status], [previousId, previousStatus]) => {
+      if (id !== undefined && id === previousId && status === 0 && previousStatus !== 0) callback()
+    },
+  )
+}
+
+// ==================== 课堂 ====================
+const lessonStore = useLessonStore()
+
+watch(
+  () => ctx.value.entry === "problem" && userStore.isAuthed,
+  (want) => {
+    // 接口要求登录；没登录就没有这一条
+    if (want) lessonStore.load()
+  },
+  { immediate: true },
+)
+
+const lesson = computed(() => {
+  if (ctx.value.entry !== "problem" || !userStore.isAuthed) return null
+  const list = lessonStore.activity?.problems ?? []
+  const index = list.findIndex(
+    (item) => item.problemDisplayId.toLowerCase() === currentId.value.toLowerCase(),
+  )
+  if (index < 0) return null
+  const chips: ChipItem[] = list.map((item) => ({
+    displayId: item.problemDisplayId,
+    title: item.title,
+    status:
+      item.myStatus === "accepted"
+        ? "done"
+        : item.myStatus === "tried"
+          ? "tried"
+          : ("none" as const),
+    to: `/problem/${item.problemDisplayId}`,
+  }))
+  return {
+    chips,
+    done: list.filter((item) => item.myStatus === "accepted").length,
+    total: list.length,
+    previous: chips[index - 1]?.to ?? null,
+    next: chips[index + 1]?.to ?? null,
+  }
+})
+
+onSolvedHere(() => {
+  if (ctx.value.entry !== "problem" || !lessonStore.includes(currentId.value)) return
+  lessonStore.markAccepted(currentId.value)
+  lessonStore.load(true)
+})
+
+// ==================== 题单 ====================
+const problemSet = ref<ProblemSet | null>(null)
+const setProblems = ref<ProblemSetProblem[]>([])
+
+watch(
+  () => ctx.value.problemSetId,
+  async (id) => {
+    problemSet.value = null
+    setProblems.value = []
+    if (!id) return
+    try {
+      const [detail, problems] = await Promise.all([
+        getProblemSetDetail(Number(id)),
+        getProblemSetProblems(Number(id)),
+      ])
+      // 拉的这一会儿已经离开了这个题单
+      if (ctx.value.problemSetId !== id) return
+      problemSet.value = detail
+      setProblems.value = problems
+    } catch {
+      // 拉不到就没有题单条，不影响做题
+    }
+  },
+  { immediate: true },
+)
+
+const setBar = computed(() => {
+  if (!problemSet.value) return null
+  const list = setProblems.value
+  const index = list.findIndex(
+    (item) => item.problem._id.toLowerCase() === currentId.value.toLowerCase(),
+  )
+  const link = (item: ProblemSetProblem | undefined): RouteLocationRaw | null =>
+    item
+      ? {
+          name: "problemset problem",
+          params: { problemSetId: ctx.value.problemSetId, problemID: item.problem._id },
+        }
+      : null
+  const done = list.filter((item) => item.isCompleted).length
+  return {
+    title: problemSet.value.title,
+    home: { name: "problemset", params: { problemSetId: ctx.value.problemSetId } },
+    done,
+    total: list.length,
+    percentage: list.length ? (done / list.length) * 100 : 0,
+    position: index >= 0 ? index + 1 : null,
+    previous: index >= 0 ? link(list[index - 1]) : null,
+    next: index >= 0 ? link(list[index + 1]) : null,
+  }
+})
+
+// 判题那一路已经记了账（judge/run.ts），这里只是把这一条就地改掉，不用重拉
+onSolvedHere(() => {
+  const item = setProblems.value.find(
+    (row) => row.problem._id.toLowerCase() === currentId.value.toLowerCase(),
+  )
+  if (item) item.isCompleted = true
+})
+
+// ==================== 比赛 ====================
+const contestStore = useContestStore()
+
+// 比赛页（contest/detail.vue）和比赛题目页是两条并列的路由，不会同时挂着：
+// 从比赛页点进来时那边已经 clear 过了，这里自己再拉一遍
+// 卸载时路由已经是下一页的了，ctx 里的 contestId 不作数，自己记着
+let contestLoaded = false
+watch(
+  () => ctx.value.contestId,
+  (id) => {
+    if (!id) return
+    contestLoaded = true
+    contestStore.init(id).catch(() => {})
+  },
+  { immediate: true },
+)
+onBeforeUnmount(() => {
+  // 停掉倒计时的表
+  if (contestLoaded) contestStore.clear()
+})
+
+const contestBar = computed(() => {
+  const contest = contestStore.contest
+  if (ctx.value.entry !== "contest" || !contest || String(contest.id) !== ctx.value.contestId)
+    return null
+  const chips: ChipItem[] = contestStore.problems.map((row) => ({
+    displayId: row._id,
+    title: row.title,
+    status: row.status === "passed" ? "done" : row.status === "failed" ? "tried" : "none",
+    to: `/contest/${ctx.value.contestId}/problem/${row._id}`,
+  }))
+  return {
+    title: contest.title,
+    chips,
+    remaining: contestStore.remaining,
+    home: { name: "contest problems", params: { contestID: ctx.value.contestId } },
+    rank: { name: "contest rank", params: { contestID: ctx.value.contestId } },
+  }
+})
+
+onSolvedHere(() => {
+  const row = contestStore.problems.find(
+    (item) => item._id.toLowerCase() === currentId.value.toLowerCase(),
+  )
+  if (row) row.status = "passed"
+})
+</script>
+
+<template>
+  <!-- 课堂 -->
+  <div v-if="lesson" class="context-bar">
+    <span class="lead">
+      这节课 <b>做完 {{ lesson.done }}/{{ lesson.total }}</b>
+    </span>
+    <ProblemChips :items="lesson.chips" :current="currentId" />
+    <n-button-group v-if="lesson.total <= CHIPS_FIT" size="small" class="steps">
+      <n-button :disabled="!lesson.previous" title="上一题" @click="$router.push(lesson.previous!)">
+        ‹
+      </n-button>
+      <n-button :disabled="!lesson.next" title="下一题" @click="$router.push(lesson.next!)">
+        ›
+      </n-button>
+    </n-button-group>
+  </div>
+
+  <!-- 题单 -->
+  <div v-else-if="setBar" class="context-bar">
+    <router-link :to="setBar.home" class="back" :title="`回到题单：${setBar.title}`">
+      <span aria-hidden="true">‹</span>
+      <span class="name">{{ setBar.title }}</span>
+    </router-link>
+    <n-progress
+      class="set-progress"
+      type="line"
+      :percentage="setBar.percentage"
+      :show-indicator="false"
+      :height="6"
+      status="success"
+    />
+    <span class="lead">
+      <b>做完 {{ setBar.done }}/{{ setBar.total }}</b>
+      <template v-if="setBar.position"> · 第 {{ setBar.position }} 题</template>
+    </span>
+    <n-button-group size="small" class="steps">
+      <n-button :disabled="!setBar.previous" title="上一题" @click="$router.push(setBar.previous!)">
+        ‹
+      </n-button>
+      <n-button :disabled="!setBar.next" title="下一题" @click="$router.push(setBar.next!)">
+        ›
+      </n-button>
+    </n-button-group>
+  </div>
+
+  <!-- 比赛 -->
+  <div v-else-if="contestBar" class="context-bar">
+    <router-link :to="contestBar.home" class="back" :title="`回到比赛：${contestBar.title}`">
+      <span aria-hidden="true">‹</span>
+      <span class="name">{{ contestBar.title }}</span>
+    </router-link>
+    <ProblemChips :items="contestBar.chips" :current="currentId" />
+    <span v-if="contestBar.remaining" class="lead remaining">
+      还剩 <b>{{ contestBar.remaining }}</b>
+    </span>
+    <span v-else class="lead">已结束</span>
+    <router-link :to="contestBar.rank" class="steps">
+      <n-button size="small">排名</n-button>
+    </router-link>
+  </div>
+</template>
+
+<style scoped>
+.context-bar {
+  height: 44px;
+  display: flex;
+  align-items: center;
+  gap: 10px;
+  padding: 0 2px;
+  flex: none;
+  min-width: 0;
+  font-size: 14px;
+  white-space: nowrap;
+}
+
+.lead {
+  flex: none;
+}
+
+.remaining b {
+  font-variant-numeric: tabular-nums;
+}
+
+.back {
+  display: inline-flex;
+  align-items: center;
+  gap: 2px;
+  /* 名字不跟题号那段抢地方：题号多了本来就能横向滚，名字挤成两个字就认不出了 */
+  flex: none;
+  max-width: 160px;
+  color: inherit;
+  text-decoration: none;
+  font-weight: 600;
+}
+
+.back:hover {
+  text-decoration: underline;
+}
+
+.name {
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
+
+.set-progress {
+  flex: 1 1 60px;
+  min-width: 40px;
+}
+
+.steps {
+  flex: none;
+  margin-left: auto;
+}
+</style>
diff --git a/apps/web/src/oj/problem/components/EditorToolbar.vue b/apps/web/src/oj/problem/components/EditorToolbar.vue
index 22fbc47..edfd939 100644
--- a/apps/web/src/oj/problem/components/EditorToolbar.vue
+++ b/apps/web/src/oj/problem/components/EditorToolbar.vue
@@ -19,6 +19,7 @@ import type { LANGUAGE } from "utils/types"
 import { Icon } from "@iconify/vue"
 import { NFlex } from "naive-ui"
 import SubmitCode from "./SubmitCode.vue"
+import { useProblemPageContext } from "../composables/problemPageContext"
 
 const SubmitFlowchart = defineAsyncComponent(() => import("./SubmitFlowchart.vue"))
 // 只有老师看得见（下面的弹框挂了 isTeacherOrAbove），静态 import 的话每个学生
@@ -38,8 +39,8 @@ const emit = defineEmits<{
 }>()
 
 const message = useMessage()
-const route = useRoute()
 const router = useRouter()
+const ctx = useProblemPageContext()
 const userStore = useUserStore()
 const codeStore = useCodeStore()
 const problemStore = useProblemStore()
@@ -63,8 +64,6 @@ const canRunSamples = computed(
     codeStore.code.language !== "SQL",
 )
 
-// 计算属性
-const isContestMode = computed(() => route.name === "contest problem")
 const buttonSize = computed(() => (isDesktop.value ? "medium" : "small"))
 // 可见条件沿用原来的 showSyncFeature，再加上「不是教师」——
 // 教师端的入口在顶栏，不在题目页
@@ -76,7 +75,7 @@ const showHelpButton = computed(
     // 演示模式下协作通道是断开的（见 App.vue），按钮点了也没人收
     !userStore.demoMode &&
     codeStore.code.language !== "Flowchart" &&
-    !isContestMode.value,
+    ctx.value.help,
 )
 
 /**
@@ -124,29 +123,14 @@ const toggleHelp = () => {
     collabStore.requestHelp(problem.value!._id, codeStore.code.language)
 }
 
-const showGoSubmissionButton = computed(() => {
-  if (isContestMode.value) return true
-  else if (userStore.isAdminRole) return true
-  else if (userStore.showSubmissions) return true
-  else return false
-})
-
 const menuOptions = computed<DropdownOption[]>(() => {
   const options: DropdownOption[] = []
-  // 移动端额外收纳桌面端常驻的两项
-  if (!isDesktop.value) {
-    if (showGoSubmissionButton.value) {
-      options.push({
-        label: "本题提交",
-        key: "submissions",
-      })
-    }
-    if (userStore.isTeacherOrAbove) {
-      options.push({
-        label: "课堂统计",
-        key: "statistics",
-      })
-    }
+  // 移动端额外收纳桌面端常驻的「课堂统计」。「本题提交」挪到了「我的提交」抽屉的底部
+  if (!isDesktop.value && userStore.isTeacherOrAbove) {
+    options.push({
+      label: "课堂统计",
+      key: "statistics",
+    })
   }
   if (codeStore.code.language !== "Flowchart") {
     if (codeStore.code.language !== "SQL") {
@@ -179,9 +163,6 @@ const menuOptions = computed<DropdownOption[]>(() => {
 
 const handleMenuSelect = (key: string) => {
   switch (key) {
-    case "submissions":
-      goSubmissions()
-      break
     case "statistics":
       statisticPanel.value = true
       break
@@ -238,26 +219,14 @@ const goTestCat = () => {
   const data = {
     lang,
     code: codeStore.code.value,
-    input: problemStore.problem?.samples[0].input,
+    // 没有例子的题原来在这里抛 TypeError，点了没反应
+    input: problemStore.problem?.samples[0]?.input ?? "",
   }
   const base64 = compressToBase64(JSON.stringify(data))
   const url = `${import.meta.env.PUBLIC_CODE_URL}?share=${encodeURIComponent(base64)}`
   window.open(url, "_blank")
 }
 
-const goSubmissions = () => {
-  const name = route.params.contestID ? "contest submissions" : "submissions"
-  const target = { name, query: { problem: problem.value!._id } }
-  // 协作中走新标签：教师端「页面即协作现场」，跳走这一页协作就结束了
-  // （求助会退回排队，但老师还得再接一次）。而「看看这学生都交了什么」恰好是
-  // 协作时最常点的一个按钮 —— 这是整条工具栏上唯一会跳路由的按钮
-  if (showCollabBar.value) {
-    window.open(router.resolve(target).href, "_blank")
-    return
-  }
-  router.push(target)
-}
-
 const goEdit = () => {
   const url = problem.value!.contestId
     ? `/admin/contest/${problem.value!.contestId}/problem/edit/${problem.value!.id}`
@@ -294,10 +263,6 @@ const goEdit = () => {
 
     <SubmitCode v-else />
 
-    <n-button v-if="isDesktop && showGoSubmissionButton" :size="buttonSize" @click="goSubmissions">
-      本题提交
-    </n-button>
-
     <n-button
       v-if="isDesktop && userStore.isTeacherOrAbove"
       :size="buttonSize"
@@ -306,7 +271,7 @@ const goEdit = () => {
       课堂统计
     </n-button>
 
-    <!-- 自测猫 / 复制代码 / 重置代码 / 编辑题目 收进下拉菜单；移动端再加上本题提交 / 课堂统计 -->
+    <!-- 自测猫 / 复制代码 / 重置代码 / 编辑题目 收进下拉菜单；移动端再加上课堂统计 -->
     <n-dropdown
       v-if="menuOptions.length"
       trigger="click"
diff --git a/apps/web/src/oj/problem/components/LessonNext.vue b/apps/web/src/oj/problem/components/LessonNext.vue
index b8d43b4..c626aba 100644
--- a/apps/web/src/oj/problem/components/LessonNext.vue
+++ b/apps/web/src/oj/problem/components/LessonNext.vue
@@ -1,17 +1,16 @@
 <script setup lang="ts">
-import { getClassActivity } from "oj/api"
-import type { ClassActivity } from "utils/types"
+import { useLessonStore } from "oj/store/lesson"
 
 /**
  * 通过之后告诉学生「这节课的下一题是哪道」。
  *
  * 72% 的提交一次就通过，每次通过之后学生都得回首页、或者再问一遍题号去找下一道。
- * 这节课的题就是首页「班里在做」那几道（老师在课堂看板布置的，或者从同班提交推断的），
- * 这里直接拿同一个接口，给出下一道没做完的。
+ * 这节课的题就是首页「班里在做」那几道，和左栏顶上的课堂条读同一份（lesson store）；
+ * 通过的那一刻课堂条已经把这道标成做完、并且重拉了一次。
  *
  * 「下一道」是按列表顺序排在这道**后面**、还没通过的第一道，后面都做完了再从头找 ——
  * 学生常常跳着做，先做完了第 3 道再回头做第 1 道。当前这道本身不看它的 myStatus：
- * 接口是通过之前那一刻的状态，这时候它刚刚才通过。
+ * 重拉回来之前，它还是通过之前那一刻的状态。
  *
  * 这道题不在这节课的列表里（学生在做别的）就什么都不显示。
  */
@@ -20,14 +19,13 @@ const props = defineProps<{
   problemDisplayId: string
 }>()
 
-const activity = ref<ClassActivity | null>(null)
+const lessonStore = useLessonStore()
 
-onMounted(async () => {
-  activity.value = await getClassActivity().catch(() => null)
-})
+// 一般课堂条早就拉过了，这里只是兜底（旧了才拉）
+onMounted(() => lessonStore.load())
 
 const lesson = computed(() => {
-  const list = activity.value?.problems ?? []
+  const list = lessonStore.activity?.problems ?? []
   const current = props.problemDisplayId.toLowerCase()
   const index = list.findIndex((item) => item.problemDisplayId.toLowerCase() === current)
   if (index < 0) return null
@@ -37,7 +35,7 @@ const lesson = computed(() => {
   return { total: list.length, next: rest[0] ?? null, remaining: rest.length }
 })
 
-const label = computed(() => (activity.value?.source === "teacher" ? "老师布置的题" : "这节课的题"))
+const label = computed(() => lessonStore.label)
 </script>
 
 <template>
diff --git a/apps/web/src/oj/problem/components/MyFlowchart.vue b/apps/web/src/oj/problem/components/MyFlowchart.vue
new file mode 100644
index 0000000..fcfe131
--- /dev/null
+++ b/apps/web/src/oj/problem/components/MyFlowchart.vue
@@ -0,0 +1,66 @@
+<script setup lang="ts">
+import { useMyFlowchartStore } from "shared/store/myFlowchart"
+import { useMermaid } from "shared/composables/useMermaid"
+
+/**
+ * 学生自己画到 A/S 的那张流程图。题面里是缩略的一小块（compact），点「放大看」弹出整张。
+ * 原来是左栏单独一个「我的流程图」页签，评到 A/S 时还会把学生强行切过去。
+ */
+const props = defineProps<{ compact?: boolean }>()
+
+const store = useMyFlowchartStore()
+const { renderError, renderFlowchart } = useMermaid()
+const mermaidContainer = useTemplateRef<HTMLElement>("mermaidContainer")
+
+watch(
+  () => store.mermaidCode,
+  async (code) => {
+    if (!code) return
+    await nextTick()
+    await renderFlowchart(mermaidContainer.value, code)
+  },
+  { immediate: true },
+)
+</script>
+
+<template>
+  <div>
+    <n-alert v-if="renderError" type="error" title="流程图渲染失败" size="small">
+      {{ renderError }}
+    </n-alert>
+    <div
+      v-show="!renderError"
+      ref="mermaidContainer"
+      class="flowchart-container"
+      :class="{ compact: props.compact }"
+    ></div>
+  </div>
+</template>
+
+<style scoped>
+.flowchart-container {
+  width: 100%;
+  min-height: 500px;
+  display: flex;
+  justify-content: center;
+  align-items: flex-start;
+}
+
+:deep(.flowchart-container > svg) {
+  width: 100%;
+  height: auto;
+}
+
+.flowchart-container.compact {
+  min-height: 0;
+  height: 150px;
+  align-items: center;
+}
+
+/* 缩略图按高度缩：流程图一般是竖长的，按宽度铺满的话 150px 里只看得见开头两个框 */
+:deep(.flowchart-container.compact > svg) {
+  width: auto;
+  max-width: 100%;
+  height: 100%;
+}
+</style>
diff --git a/apps/web/src/oj/problem/components/MyFlowchartTab.vue b/apps/web/src/oj/problem/components/MyFlowchartTab.vue
deleted file mode 100644
index 678bc80..0000000
--- a/apps/web/src/oj/problem/components/MyFlowchartTab.vue
+++ /dev/null
@@ -1,42 +0,0 @@
-<script setup lang="ts">
-import { useMyFlowchartStore } from "shared/store/myFlowchart"
-import { useMermaid } from "shared/composables/useMermaid"
-
-const store = useMyFlowchartStore()
-const { renderError, renderFlowchart } = useMermaid()
-const mermaidContainer = useTemplateRef<HTMLElement>("mermaidContainer")
-
-watch(
-  () => store.mermaidCode,
-  async (code) => {
-    if (!code) return
-    await nextTick()
-    await renderFlowchart(mermaidContainer.value, code)
-  },
-  { immediate: true },
-)
-</script>
-
-<template>
-  <div style="padding: 8px 0">
-    <n-alert v-if="renderError" type="error" title="渲染失败" size="small">
-      {{ renderError }}
-    </n-alert>
-    <div v-show="!renderError" ref="mermaidContainer" class="flowchart-container"></div>
-  </div>
-</template>
-
-<style scoped>
-.flowchart-container {
-  width: 100%;
-  min-height: 500px;
-  display: flex;
-  justify-content: center;
-  align-items: flex-start;
-}
-
-:deep(.flowchart-container > svg) {
-  width: 100%;
-  height: auto;
-}
-</style>
diff --git a/apps/web/src/oj/problem/components/ProblemChips.vue b/apps/web/src/oj/problem/components/ProblemChips.vue
new file mode 100644
index 0000000..8fc0430
--- /dev/null
+++ b/apps/web/src/oj/problem/components/ProblemChips.vue
@@ -0,0 +1,124 @@
+<script setup lang="ts">
+import { useThemeVars } from "naive-ui"
+import type { RouteLocationRaw } from "vue-router"
+
+/**
+ * 上下文条里的一排题号（课堂、比赛共用）。只放题号，题目名在鼠标停上去时给。
+ *
+ * 状态用图标区分，不只靠颜色：✓ 做完（实心绿）/ ! 做过没对（橙）/ 灰底 没做；当前题描边。
+ * 一节课一般 5 道以内，一行放得下；多了（比赛、老师一次布置了一长串）就横向滚动，
+ * 当前题保持在视野里。
+ */
+export interface ChipItem {
+  displayId: string
+  title: string
+  status: "done" | "tried" | "none"
+  to: RouteLocationRaw
+}
+
+const props = defineProps<{
+  items: ChipItem[]
+  current: string
+}>()
+
+const theme = useThemeVars()
+
+const STATUS_TEXT = { done: "做完了", tried: "做过，还没对", none: "还没做" } as const
+
+const isCurrent = (item: ChipItem) => item.displayId.toLowerCase() === props.current.toLowerCase()
+
+const scroller = useTemplateRef<HTMLElement>("scroller")
+
+// 换题之后把当前那一颗滚进来。`nearest`：本来就看得见就不动，免得一换题整排跳一下
+watch(
+  () => [props.current, props.items.length],
+  async () => {
+    await nextTick()
+    scroller.value
+      ?.querySelector<HTMLElement>(".chip.current")
+      ?.scrollIntoView({ block: "nearest", inline: "nearest" })
+  },
+  { immediate: true },
+)
+</script>
+
+<template>
+  <div ref="scroller" class="chips">
+    <n-tooltip v-for="item in items" :key="item.displayId" :delay="300">
+      <template #trigger>
+        <router-link
+          :to="item.to"
+          class="chip"
+          :class="[item.status, { current: isCurrent(item) }]"
+          :aria-label="`${item.displayId} ${item.title}（${STATUS_TEXT[item.status]}）`"
+          :aria-current="isCurrent(item) ? 'page' : undefined"
+        >
+          <!-- 用字符不用图标：图标是从 Iconify 源现拉的，拉不到时状态就只剩颜色 -->
+          <span v-if="item.status === 'done'" aria-hidden="true">✓</span>
+          <span v-else-if="item.status === 'tried'" aria-hidden="true">!</span>
+          <span>{{ item.displayId }}</span>
+        </router-link>
+      </template>
+      {{ item.displayId }} {{ item.title }} · {{ STATUS_TEXT[item.status] }}
+    </n-tooltip>
+  </div>
+</template>
+
+<style scoped>
+.chips {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+  flex: 0 1 auto;
+  min-width: 0;
+  overflow-x: auto;
+  scrollbar-width: thin;
+  /* 描边的外圈别被裁掉 */
+  padding: 3px 2px;
+}
+
+.chip {
+  flex: none;
+  display: inline-flex;
+  align-items: center;
+  gap: 3px;
+  height: 26px;
+  padding: 0 9px;
+  border-radius: 13px;
+  font-size: 13px;
+  font-variant-numeric: tabular-nums;
+  text-decoration: none;
+  color: v-bind("theme.textColor2");
+  background-color: rgba(128, 128, 128, 0.12);
+  border: 1px solid transparent;
+}
+
+.chip.done {
+  color: #fff;
+  background-color: v-bind("theme.successColor");
+}
+
+.chip.tried {
+  color: v-bind("theme.warningColor");
+  background-color: rgba(240, 160, 32, 0.12);
+  border-color: rgba(240, 160, 32, 0.5);
+}
+
+.chip.current {
+  border-color: v-bind("theme.primaryColor");
+  box-shadow: 0 0 0 1px v-bind("theme.primaryColor");
+  font-weight: 600;
+}
+
+/* 当前题做完了：实心绿，外面再套一圈（中间隔一道底色） */
+.chip.done.current {
+  border-color: v-bind("theme.successColor");
+  box-shadow:
+    0 0 0 2px v-bind("theme.bodyColor"),
+    0 0 0 3px v-bind("theme.successColor");
+}
+
+.chip:hover {
+  filter: brightness(0.95);
+}
+</style>
diff --git a/apps/web/src/oj/problem/components/ProblemContent.vue b/apps/web/src/oj/problem/components/ProblemContent.vue
index eaba017..b0f3301 100644
--- a/apps/web/src/oj/problem/components/ProblemContent.vue
+++ b/apps/web/src/oj/problem/components/ProblemContent.vue
@@ -12,13 +12,18 @@ import { MdPreview } from "md-editor-v3"
 import "md-editor-v3/lib/preview.css"
 import { getSimilarProblems } from "oj/api"
 import SQLDataTable from "./SQLDataTable.vue"
+import { useFlowchartStore } from "oj/store/flowchart"
+import { useMyFlowchartStore } from "shared/store/myFlowchart"
+import { useUserStore } from "shared/store/user"
+import { useProblemPageContext } from "../composables/problemPageContext"
+
+const ProblemFlowchart = defineAsyncComponent(() => import("./ProblemFlowchart.vue"))
+const MyFlowchart = defineAsyncComponent(() => import("./MyFlowchart.vue"))
 
 const isDark = useDark()
-const route = useRoute()
 const problemStore = useProblemStore()
-const { problem } = storeToRefs(problemStore)
-
-const problemSetId = computed(() => route.params.problemSetId)
+const { problem, languages } = storeToRefs(problemStore)
+const ctx = useProblemPageContext()
 
 // SQL 题：隐藏输入/输出/例子，改为渲染数据表与期望结果
 const isSQL = computed(() => !!problem.value?.sqlConfig)
@@ -40,9 +45,8 @@ const similarLoaded = ref(false)
 
 async function loadSimilarProblems() {
   if (similarLoaded.value || !problem.value) return
-  // 比赛题不推荐：接口按 displayId 在**公开题库**里找，比赛题的编号默认是 1/2/3，
-  // 一般白跑一趟 404，撞上同号公开题时反而会在比赛中把题库列给学生。
-  if (problem.value.contestId !== null) return
+  // 比赛、题单里不推荐（理由见 problemPageContext 那张表）
+  if (!ctx.value.similar) return
   try {
     similarProblems.value = await getSimilarProblems(problem.value._id)
   } catch {
@@ -71,14 +75,43 @@ watch(
   { immediate: true },
 )
 
-const hasTriedButNotPassed = computed(() => {
-  return (
-    problem.value?.myStatus !== undefined &&
-    problem.value?.myStatus !== null &&
-    problem.value?.myStatus !== 0
-  )
+/**
+ * 标题下的状态标签。原来是题面最上面两条整宽的提示（「本题已经被你解决啦」「尝试过但还没有
+ * 通过」），占掉一屏里最值钱的那几行。题单里不给（入口差异表）。
+ */
+const myStatus = computed(() => {
+  const status = problem.value?.myStatus
+  if (!ctx.value.statusTag || status === undefined || status === null) return null
+  return status === 0 ? "solved" : "tried"
 })
 
+/** 「限时 1 秒」：学生不需要 ms / MB。1000 → 1，1500 → 1.5 */
+const timeLimitText = computed(() => {
+  const ms = problem.value?.timeLimit ?? 0
+  return `限时 ${Number((ms / 1000).toFixed(2))} 秒`
+})
+
+// ==================== 流程图小节 ====================
+// 同一个位置二选一：老师给的参考图（showFlowchart，默认折叠），或者学生自己画到 A/S 的
+// 那张（allowFlowchart）。两个开关在后台是互斥的（admin/problem/detail.vue）；后端在
+// allowFlowchart 为真时会把 mermaidCode 置成 null，不能把标准答案下发给正要自己画图的学生。
+const canShowReferenceFlowchart = computed(
+  () => !!problem.value?.showFlowchart && !!problem.value?.mermaidCode,
+)
+const myFlowchartStore = useMyFlowchartStore()
+const flowchartStore = useFlowchartStore()
+const userStore = useUserStore()
+const myFlowchartZoom = ref(false)
+
+// 这道题能画流程图，就去查画到 A/S 没有 —— 原来要先切到「流程图」这门「语言」才查
+watch(
+  () => [problem.value?.id, languages.value.includes("Flowchart"), userStore.isAuthed] as const,
+  ([id, canDraw, authed]) => {
+    if (id && canDraw && authed) flowchartStore.ensureLoaded()
+  },
+  { immediate: true },
+)
+
 // 例子只是摆出来。原来每个例子旁有个「测试」按钮（结果只给通过 / 不通过、2 秒后复位），
 // 现在试跑统一走工具栏的「运行例子」和结果页签的「自己输入」
 const samples = computed(() => problem.value?.samples ?? [])
@@ -98,27 +131,6 @@ const astRequirements = computed(() => Object.entries(problem.value?.astRequirem
 
 <template>
   <div v-if="problem">
-    <template v-if="!problemSetId">
-      <!-- 已通过 -->
-      <n-alert
-        class="status-alert"
-        v-if="problem.myStatus === 0"
-        type="success"
-        title="🎉 本 题 已 经 被 你 解 决 啦"
-      >
-      </n-alert>
-
-      <!-- 尝试过但未通过 -->
-      <n-alert
-        class="status-alert"
-        v-else-if="hasTriedButNotPassed"
-        type="warning"
-        title="💪 你已经尝试过这道题，但还没有通过"
-      >
-        不要放弃！仔细检查代码逻辑，或者寻求 AI 的帮助获取灵感。
-      </n-alert>
-    </template>
-
     <header class="problem-head">
       <n-flex align="center" :size="10" :wrap="false">
         <n-tag :bordered="false">{{ problem._id }}</n-tag>
@@ -133,9 +145,13 @@ const astRequirements = computed(() => Object.entries(problem.value?.astRequirem
         >
           {{ DIFFICULTY[problem.difficulty] }}
         </n-tag>
-        <n-text depth="3" v-if="!isSQL">
-          时间限制 {{ problem.timeLimit }} ms · 内存限制 {{ problem.memoryLimit }} MB
-        </n-text>
+        <n-tag v-if="myStatus === 'solved'" size="small" type="success" :bordered="false" round>
+          ✓ 已解决
+        </n-tag>
+        <n-tag v-else-if="myStatus === 'tried'" size="small" type="warning" :bordered="false" round>
+          ! 尝试过，还没通过
+        </n-tag>
+        <n-text depth="3" v-if="!isSQL">{{ timeLimitText }}</n-text>
       </n-flex>
     </header>
 
@@ -188,6 +204,41 @@ const astRequirements = computed(() => Object.entries(problem.value?.astRequirem
       />
     </template>
 
+    <n-collapse v-if="canShowReferenceFlowchart" class="flowchart-section">
+      <n-collapse-item name="reference">
+        <template #header>
+          <span class="title collapse-title">
+            <Icon icon="vscode-icons:file-type-drawio"></Icon>
+            参考流程图
+          </span>
+        </template>
+        <ProblemFlowchart />
+      </n-collapse-item>
+    </n-collapse>
+
+    <section v-else-if="myFlowchartStore.showing" class="flowchart-section">
+      <n-flex align="center" justify="space-between">
+        <h3 class="title">
+          <Icon icon="vscode-icons:file-type-drawio"></Icon>
+          你画的流程图
+        </h3>
+        <n-button text type="primary" size="small" @click="myFlowchartZoom = true">
+          放大看 ›
+        </n-button>
+      </n-flex>
+      <div class="my-flowchart" role="button" @click="myFlowchartZoom = true">
+        <MyFlowchart compact />
+      </div>
+      <n-modal
+        v-model:show="myFlowchartZoom"
+        preset="card"
+        title="你画的流程图"
+        :style="{ maxWidth: '900px' }"
+      >
+        <MyFlowchart />
+      </n-modal>
+    </section>
+
     <template v-if="!isSQL">
       <section v-for="(sample, index) of samples" :key="index" class="sample">
         <n-flex align="center" justify="space-between" class="sample-head">
@@ -292,7 +343,7 @@ const astRequirements = computed(() => Object.entries(problem.value?.astRequirem
     </div>
 
     <!-- 相似题目推荐 -->
-    <div v-if="similarProblems.length > 0">
+    <div v-if="ctx.similar && similarProblems.length > 0">
       <n-divider />
       <h3 class="title">
         <Icon icon="streamline-ultimate-color:like"></Icon>
@@ -447,8 +498,19 @@ const astRequirements = computed(() => Object.entries(problem.value?.astRequirem
   font-family: Monaco, Consolas, monospace;
 }
 
-.status-alert {
-  margin-bottom: 16px;
+.flowchart-section {
+  margin-top: 20px;
+}
+
+.collapse-title {
+  margin: 0;
+}
+
+.my-flowchart {
+  cursor: zoom-in;
+  border-radius: 6px;
+  background-color: rgba(128, 128, 128, 0.06);
+  padding: 8px;
 }
 
 .sqlTableName {
diff --git a/apps/web/src/oj/problem/components/ProblemDrawer.vue b/apps/web/src/oj/problem/components/ProblemDrawer.vue
new file mode 100644
index 0000000..eb2a7a4
--- /dev/null
+++ b/apps/web/src/oj/problem/components/ProblemDrawer.vue
@@ -0,0 +1,120 @@
+<script setup lang="ts">
+import { storeToRefs } from "pinia"
+import { useProblemStore } from "oj/store/problem"
+import { useCollabStore } from "shared/store/collab"
+import { useUserStore } from "shared/store/user"
+import {
+  DRAWER_TITLE,
+  useProblemPageContext,
+  type ProblemDrawer,
+} from "../composables/problemPageContext"
+
+/**
+ * 统计 / 点评 / 我的提交。原来是左栏的三个页签，课上几乎没人点，却和「题目」挤在一排；
+ * 现在收进抽屉，盖住左栏、编辑器不动。
+ *
+ * 抽屉里的内容关上就卸载：再打开时「我的提交」要重新拉，刚交的那次才看得见。
+ */
+const ProblemInfo = defineAsyncComponent(() => import("./ProblemInfo.vue"))
+const ProblemReaction = defineAsyncComponent(() => import("./ProblemReaction.vue"))
+const ProblemSubmission = defineAsyncComponent(() => import("./ProblemSubmission.vue"))
+
+const open = defineModel<ProblemDrawer | null>({ required: true })
+
+const props = defineProps<{
+  /** 桌面：挂进左栏（它得是 position: relative）；手机：不传，从底下拉起来盖住整屏 */
+  to?: string
+}>()
+
+const ctx = useProblemPageContext()
+const route = useRoute()
+const router = useRouter()
+const userStore = useUserStore()
+const collabStore = useCollabStore()
+const { problem } = storeToRefs(useProblemStore())
+
+const show = computed({
+  get: () => open.value !== null,
+  set: (value) => {
+    if (!value) open.value = null
+  },
+})
+
+// 内容和标题都按最后一次打开的来：关的时候有一段滑出去的动画，那时 open 已经是 null 了。
+// 关完 n-drawer 自己把内容卸掉
+const lastOpened = ref<ProblemDrawer>("info")
+watch(open, (key) => {
+  if (key) lastOpened.value = key
+})
+
+// 换题就关：抽屉里是上一道题的统计和提交
+watch(
+  () => problem.value?._id,
+  () => {
+    open.value = null
+  },
+)
+
+/**
+ * 「看这道题所有人的提交」，原来是工具栏上的「本题提交」。可见条件照旧：
+ * 比赛里总给（看的是这场比赛的提交），题库里要管理员或者开着提交列表。
+ */
+const showAllSubmissions = computed(
+  () => ctx.value.entry === "contest" || userStore.isAdminRole || userStore.showSubmissions,
+)
+
+function goAllSubmissions() {
+  const target = {
+    name: ctx.value.entry === "contest" ? "contest submissions" : "submissions",
+    params: ctx.value.entry === "contest" ? { contestID: route.params.contestID } : {},
+    query: { problem: problem.value!._id },
+  }
+  // 协作中走新标签：教师端「页面即协作现场」，跳走这一页协作就结束了
+  // （求助会退回排队，但老师还得再接一次）。而「看看这学生都交了什么」恰好是
+  // 协作时最常点的一个
+  const collabHere =
+    collabStore.room !== null &&
+    collabStore.room.problemId === problem.value?._id &&
+    userStore.isTeacherOrAbove
+  if (collabHere) {
+    window.open(router.resolve(target).href, "_blank")
+    return
+  }
+  router.push(target)
+}
+</script>
+
+<template>
+  <n-drawer
+    v-model:show="show"
+    :to="props.to"
+    :placement="props.to ? 'left' : 'bottom'"
+    :width="props.to ? '100%' : undefined"
+    :height="props.to ? undefined : '85%'"
+    :trap-focus="false"
+    :block-scroll="!props.to"
+  >
+    <n-drawer-content :title="DRAWER_TITLE[lastOpened]" closable :native-scrollbar="false">
+      <ProblemInfo v-if="lastOpened === 'info'" />
+      <ProblemReaction v-else-if="lastOpened === 'reaction'" />
+      <template v-else>
+        <ProblemSubmission />
+        <n-button
+          v-if="showAllSubmissions"
+          class="all-submissions"
+          text
+          type="primary"
+          @click="goAllSubmissions"
+        >
+          看这道题所有人的提交 ›
+        </n-button>
+      </template>
+    </n-drawer-content>
+  </n-drawer>
+</template>
+
+<style scoped>
+.all-submissions {
+  margin-top: 12px;
+}
+</style>
diff --git a/apps/web/src/oj/problem/components/ProblemSubmission.vue b/apps/web/src/oj/problem/components/ProblemSubmission.vue
index 515b502..7bebe9d 100644
--- a/apps/web/src/oj/problem/components/ProblemSubmission.vue
+++ b/apps/web/src/oj/problem/components/ProblemSubmission.vue
@@ -88,6 +88,8 @@ const loading = ref(false)
 
 const submissions = ref<SubmissionListItem[]>([])
 const total = ref(0)
+// 拉回来之前别说「还没交过」
+const listed = ref(false)
 const query = reactive({
   limit: 10,
   page: 1,
@@ -127,6 +129,7 @@ async function listSubmissions() {
   })
   submissions.value = res.results
   total.value = res.total
+  listed.value = true
 }
 
 async function getRankOfThisProblem() {
@@ -288,6 +291,7 @@ watch(query, listSubmissions)
     </n-flex>
 
     <n-data-table v-if="submissions.length > 0" striped :columns="columns" :data="submissions" />
+    <n-empty v-else-if="listed" class="tip" description="这道题你还没有交过" />
     <Pagination :total="total" v-model:limit="query.limit" v-model:page="query.page" />
   </template>
 
diff --git a/apps/web/src/oj/problem/components/SubmissionEffects.vue b/apps/web/src/oj/problem/components/SubmissionEffects.vue
index 717b5ea..1d2092a 100644
--- a/apps/web/src/oj/problem/components/SubmissionEffects.vue
+++ b/apps/web/src/oj/problem/components/SubmissionEffects.vue
@@ -7,6 +7,7 @@ import { useSubmissionStore } from "oj/store/submission"
 import { useFireworks } from "oj/problem/composables/useFireworks"
 import { useBreakpoints } from "shared/composables/breakpoints"
 import { SubmissionStatus } from "utils/constants"
+import { useProblemPageContext } from "../composables/problemPageContext"
 
 /**
  * 判完之后「该发生什么」：失败计数、标成已解决、烟花、点评、回题单。
@@ -24,11 +25,8 @@ const submissionStore = useSubmissionStore()
 const { problem } = storeToRefs(problemStore)
 const { submission } = storeToRefs(submissionStore)
 
-const route = useRoute()
 const router = useRouter()
-// 题目页在题库 / 比赛 / 题单三条路由之间是复用的，所以跟着路由算，不在 setup 时取一次
-const contestID = computed(() => (route.params.contestID as string) ?? "")
-const problemSetId = computed(() => (route.params.problemSetId as string) ?? "")
+const ctx = useProblemPageContext()
 
 const { isDesktop } = useBreakpoints()
 const { celebrate } = useFireworks()
@@ -106,7 +104,7 @@ const { start: goToProblemSetDelayed, stop: cancelGoToProblemSet } = useTimeoutF
     router.push({
       name: "problemset",
       params: {
-        problemSetId: problemSetId.value,
+        problemSetId: ctx.value.problemSetId,
       },
     })
   },
@@ -176,12 +174,12 @@ watch(
     celebrate()
 
     // 3. 弹出评价框。比赛里不打扰；题单里 1.5 秒后要跳回题单页，弹了也会被冲掉
-    if (!contestID.value && !problemSetId.value) {
+    if (ctx.value.reviewAfterAccepted) {
       reviewOwed.value = true
       showCommentPanelDelayed()
     }
 
-    if (problemSetId.value) {
+    if (ctx.value.backToProblemSet) {
       // 延迟回到题单页面
       goToProblemSetDelayed()
     }
diff --git a/apps/web/src/oj/problem/components/SubmissionResult.vue b/apps/web/src/oj/problem/components/SubmissionResult.vue
index 250be47..5fbdde6 100644
--- a/apps/web/src/oj/problem/components/SubmissionResult.vue
+++ b/apps/web/src/oj/problem/components/SubmissionResult.vue
@@ -19,6 +19,7 @@ import PythonErrorExplain from "./PythonErrorExplain.vue"
 import RuntimeErrorExplain from "./RuntimeErrorExplain.vue"
 import WrongAnswerExplain from "./WrongAnswerExplain.vue"
 import LessonNext from "./LessonNext.vue"
+import { useProblemPageContext } from "../composables/problemPageContext"
 import { MdPreview } from "md-editor-v3"
 import "md-editor-v3/lib/preview.css"
 import { useDark } from "@vueuse/core"
@@ -84,14 +85,11 @@ const sampleCheck = computed(() => {
 
 /**
  * 通过之后给「这节课的下一题」。比赛有自己的题目列表；从题单入口进来的，通过后
- * 1.5 秒会自动跳回题单（SubmitCode 的 goToProblemSetDelayed），这两种都不给
+ * 1.5 秒会自动跳回题单（SubmissionEffects），这两种都不给
  */
-const route = useRoute()
+const ctx = useProblemPageContext()
 const showLessonNext = computed(
-  () =>
-    props.submission?.result === SubmissionStatus.accepted &&
-    problemStore.problem?.contestId == null &&
-    !route.params.problemSetId,
+  () => props.submission?.result === SubmissionStatus.accepted && ctx.value.lessonNext,
 )
 
 const msg = computed(() => {
@@ -208,10 +206,8 @@ const columns: DataTableColumn<JudgeCaseResult>[] = [
         />
       </template>
     </n-alert>
-    <!-- key 用提交 id：同一道题再交一次、又通过了，要重新拉一遍「还剩几道」 -->
     <LessonNext
       v-if="showLessonNext && problemStore.problem"
-      :key="submission.id"
       :problem-display-id="problemStore.problem._id"
     />
     <n-flex
diff --git a/apps/web/src/oj/problem/composables/problemPageContext.ts b/apps/web/src/oj/problem/composables/problemPageContext.ts
new file mode 100644
index 0000000..0a62226
--- /dev/null
+++ b/apps/web/src/oj/problem/composables/problemPageContext.ts
@@ -0,0 +1,92 @@
+import type { RouteLocationNormalizedLoaded } from "vue-router"
+
+/**
+ * 题目页的三种入口：题库（含课堂）、题单、比赛。同一个 detail.vue 挂在三条路由上。
+ *
+ * 入口之间的差异**只在这张表里判断**。原来散在各个组件里各查各的路由：同一件事
+ * 在题单里是「禁用」、在比赛里是「隐藏」，加一处功能就得把每个组件翻一遍
+ * （见 docs/specs/2026-09-28-problem-page-redesign-design.md 第 8 节）。
+ */
+export type ProblemEntry = "problem" | "problemset" | "contest"
+
+export type ProblemDrawer = "info" | "reaction" | "submission"
+
+export const DRAWER_TITLE: Record<ProblemDrawer, string> = {
+  info: "统计",
+  reaction: "点评",
+  submission: "我的提交",
+}
+
+interface EntryRules {
+  /** 页签行右侧的抽屉，按显示顺序 */
+  drawers: readonly ProblemDrawer[]
+  /** 标题下的「已解决 / 尝试过」 */
+  statusTag: boolean
+  /** 题面末尾的相似题推荐 */
+  similar: boolean
+  /** 通过之后给「这节课的下一题」 */
+  lessonNext: boolean
+  /** 通过之后 1.5 秒弹强制点评 */
+  reviewAfterAccepted: boolean
+  /** 通过之后 1.5 秒回题单 */
+  backToProblemSet: boolean
+  /** 举手求助 */
+  help: boolean
+}
+
+const RULES: Record<ProblemEntry, EntryRules> = {
+  problem: {
+    drawers: ["info", "reaction", "submission"],
+    statusTag: true,
+    similar: true,
+    lessonNext: true,
+    reviewAfterAccepted: true,
+    backToProblemSet: false,
+    help: true,
+  },
+  // 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
+  problemset: {
+    drawers: [],
+    statusTag: false,
+    // 点进相似题就离开了题单
+    similar: false,
+    lessonNext: false,
+    // 1.5 秒后要跳回题单页，弹了也会被冲掉
+    reviewAfterAccepted: false,
+    backToProblemSet: true,
+    help: true,
+  },
+  contest: {
+    drawers: ["info", "submission"],
+    statusTag: true,
+    // 相似题接口按 displayId 在公开题库里找，比赛题的编号默认是 1/2/3，
+    // 撞上同号公开题时反而会在比赛中把题库列给学生
+    similar: false,
+    lessonNext: false,
+    reviewAfterAccepted: false,
+    backToProblemSet: false,
+    help: false,
+  },
+}
+
+export function problemEntryOf(route: RouteLocationNormalizedLoaded): ProblemEntry {
+  if (route.name === "contest problem") return "contest"
+  if (route.name === "problemset problem") return "problemset"
+  return "problem"
+}
+
+/**
+ * 当前入口和它的规则。跟着路由算、不在 setup 时取一次：三条路由之间是复用同一个页面的。
+ */
+export function useProblemPageContext() {
+  const route = useRoute()
+  return computed(() => {
+    const entry = problemEntryOf(route)
+    return {
+      entry,
+      contestId: entry === "contest" ? String(route.params.contestID ?? "") : "",
+      problemSetId: entry === "problemset" ? String(route.params.problemSetId ?? "") : "",
+      ...RULES[entry],
+    }
+  })
+}
diff --git a/apps/web/src/oj/problem/detail.vue b/apps/web/src/oj/problem/detail.vue
index 46e5718..067936e 100644
--- a/apps/web/src/oj/problem/detail.vue
+++ b/apps/web/src/oj/problem/detail.vue
@@ -11,6 +11,12 @@ import { useFlowchartStore } from "oj/store/flowchart"
 // 判完之后该发生的事（烟花、点评、回题单）。静态引入：它得在第一次判完之前就挂好
 import SubmissionEffects from "./components/SubmissionEffects.vue"
 import ResultTabLabel from "./components/ResultTabLabel.vue"
+import ContextBar from "./components/ContextBar.vue"
+import {
+  DRAWER_TITLE,
+  useProblemPageContext,
+  type ProblemDrawer as DrawerKey,
+} from "./composables/problemPageContext"
 
 // 抽成具名 loader，便于进页面时与接口并行预取编辑器 chunk。
 // 题库、比赛、题单三种入口用的是同一个编辑器：原来比赛和题单用的是另一个精简版，
@@ -19,11 +25,7 @@ import ResultTabLabel from "./components/ResultTabLabel.vue"
 const loadProblemEditor = () => import("./components/ProblemEditor.vue")
 const ProblemEditor = defineAsyncComponent(loadProblemEditor)
 const ProblemContent = defineAsyncComponent(() => import("./components/ProblemContent.vue"))
-const ProblemInfo = defineAsyncComponent(() => import("./components/ProblemInfo.vue"))
-const ProblemSubmission = defineAsyncComponent(() => import("./components/ProblemSubmission.vue"))
-const ProblemReaction = defineAsyncComponent(() => import("./components/ProblemReaction.vue"))
-const ProblemFlowchart = defineAsyncComponent(() => import("./components/ProblemFlowchart.vue"))
-const MyFlowchartTab = defineAsyncComponent(() => import("./components/MyFlowchartTab.vue"))
+const ProblemDrawer = defineAsyncComponent(() => import("./components/ProblemDrawer.vue"))
 const ResultPane = defineAsyncComponent(() => import("./components/ResultPane.vue"))
 
 interface Props {
@@ -32,7 +34,7 @@ interface Props {
   problemSetId?: string
 }
 
-const { problemID, contestID = "", problemSetId = "" } = defineProps<Props>()
+const { problemID, contestID = "" } = defineProps<Props>()
 
 const errMsg = ref("无数据")
 const route = useRoute()
@@ -41,39 +43,19 @@ const router = useRouter()
 const problemStore = useProblemStore()
 const myFlowchartStore = useMyFlowchartStore()
 const { problem } = storeToRefs(problemStore)
+const ctx = useProblemPageContext()
 
 const { isMobile, isDesktop } = useBreakpoints()
 
-// tab 选项和面板必须用同一个条件。后端在 allowFlowchart 为真时会把 mermaidCode
-// 置成 null（不能把标准答案下发给正要自己画图的学生），只看 showFlowchart 的话，
-// 两个开关同时打开就会做出一个「选项存在、面板不存在」的 tab —— URL 里带
-// ?tab=flowchart 会选中一个渲染不出任何东西的页签。
-const canShowFlowchart = computed(
-  () => !!problem.value?.showFlowchart && !!problem.value?.mermaidCode,
+/**
+ * 左栏只有「题目 / 结果」两个页签（手机上编辑器也是一个页签，排在中间）。
+ * 原来的六个页签里，流程图并进了「题目」，统计 / 点评 / 我的提交收进了抽屉 ——
+ * 见 docs/specs/2026-09-28-problem-page-redesign-design.md 第 4 节。
+ */
+const tabOptions = computed(() =>
+  isMobile.value ? ["content", "editor", "result"] : ["content", "result"],
 )
 
-const tabOptions = computed(() => {
-  // 桌面上「结果」紧跟在「题目」后面；手机上编辑器也是一个页签，「结果」排在「代码」后面
-  const options: string[] = ["content"]
-  if (!isMobile.value) options.push("result")
-  if (canShowFlowchart.value) {
-    options.push("flowchart")
-  }
-
-  if (isMobile.value) {
-    options.push("editor", "result")
-  }
-  options.push("info")
-  if (!contestID) {
-    options.push("comment")
-  }
-  if (myFlowchartStore.showing) {
-    options.push("my-flowchart")
-  }
-  options.push("submission")
-  return options
-})
-
 const currentTab = ref("content")
 
 watch(
@@ -93,11 +75,33 @@ watch(currentTab, (tab) => {
   })
 })
 
-// 交上去、或者语法检查没过：切到「结果」。提交按钮在编辑器那边，页签归这一页管
+// 「结果」第一次切过去才挂（它带着 DataTable 和 Markdown 渲染），挂上之后切走也不卸载：
+// 挂着的错误说明在编辑器里标着红，AI 提示也在渲染
+const resultMounted = ref(false)
+watch(
+  currentTab,
+  (tab) => {
+    if (tab === "result") resultMounted.value = true
+  },
+  { immediate: true },
+)
+
+const drawer = ref<DrawerKey | null>(null)
+
+function toggleDrawer(key: DrawerKey) {
+  drawer.value = drawer.value === key ? null : key
+}
+
+const drawerMenu = computed<DropdownOption[]>(() =>
+  ctx.value.drawers.map((key) => ({ label: DRAWER_TITLE[key], key })),
+)
+
+// 交上去、或者语法检查没过：切到「结果」，抽屉开着就先关掉。提交按钮在编辑器那边，页签归这一页管
 const submissionStore = useSubmissionStore()
 watch(
   () => submissionStore.resultSeq,
   () => {
+    drawer.value = null
     currentTab.value = "result"
   },
 )
@@ -105,13 +109,6 @@ watch(
 // 结果页签的标题带状态图标（ResultTabLabel），n-tab-pane 的 tab 接受渲染函数
 const resultTab = () => h(ResultTabLabel)
 
-watch(
-  () => myFlowchartStore.showing,
-  (showing) => {
-    if (showing) currentTab.value = "my-flowchart"
-  },
-)
-
 async function init() {
   // 「我的流程图」是上一道题的。这道题也画到了 A/S 的话，SubmitFlowchart 查完会再亮出来
   myFlowchartStore.hide()
@@ -169,32 +166,53 @@ onBeforeUnmount(() => {
       style="height: calc(100vh - 92px)"
     >
       <template #1>
-        <n-scrollbar style="height: 100%">
-          <n-tabs v-model:value="currentTab" type="segment">
-            <n-tab-pane name="content" tab="题目">
-              <ProblemContent />
-            </n-tab-pane>
-            <!-- 切走也不卸载：挂着的错误说明在编辑器里标着红，AI 提示也在渲染 -->
-            <n-tab-pane name="result" :tab="resultTab" display-directive="show:lazy">
-              <ResultPane />
-            </n-tab-pane>
-            <n-tab-pane v-if="canShowFlowchart" name="flowchart" tab="流程图表">
-              <ProblemFlowchart />
-            </n-tab-pane>
-            <n-tab-pane name="info" tab="题目统计" :disabled="!!problemSetId">
-              <ProblemInfo />
-            </n-tab-pane>
-            <n-tab-pane v-if="!contestID" name="comment" tab="题目点评" :disabled="!!problemSetId">
-              <ProblemReaction />
-            </n-tab-pane>
-            <n-tab-pane v-if="myFlowchartStore.showing" name="my-flowchart" tab="我的流程图">
-              <MyFlowchartTab />
-            </n-tab-pane>
-            <n-tab-pane name="submission" tab="我的提交" :disabled="!!problemSetId">
-              <ProblemSubmission />
-            </n-tab-pane>
-          </n-tabs>
-        </n-scrollbar>
+        <div class="left-pane">
+          <ContextBar />
+          <div class="tab-row">
+            <n-tabs
+              v-model:value="currentTab"
+              type="segment"
+              class="page-tabs"
+              @click="drawer = null"
+            >
+              <n-tab name="content">题目</n-tab>
+              <n-tab name="result"><ResultTabLabel /></n-tab>
+            </n-tabs>
+            <n-flex v-if="ctx.drawers.length" :size="6" :wrap="false">
+              <n-button
+                v-for="key in ctx.drawers"
+                :key="key"
+                size="small"
+                :type="drawer === key ? 'primary' : 'default'"
+                :secondary="drawer === key"
+                @click="toggleDrawer(key)"
+              >
+                {{ DRAWER_TITLE[key] }}
+              </n-button>
+            </n-flex>
+          </div>
+          <!--
+            抽屉挂在页签行下面这一块（position: relative），盖住题面、编辑器不动。
+            页签行露在外面：同一个按钮再点一下就关、点另一个就换，点「题目 / 结果」也会关
+          -->
+          <div id="problem-pane-stack" class="pane-stack">
+            <!--
+              两个页签各滚各的：读题读到底下切去看结果，结果不该也停在底下。
+              v-show 挂在外面这层 div 上 —— 直接挂在 n-scrollbar 上不生效，它自己管根节点的 style
+            -->
+            <div v-show="currentTab === 'content'" class="pane-body">
+              <n-scrollbar content-style="padding-top: 8px">
+                <ProblemContent />
+              </n-scrollbar>
+            </div>
+            <div v-if="resultMounted" v-show="currentTab === 'result'" class="pane-body">
+              <n-scrollbar content-style="padding-top: 8px">
+                <ResultPane />
+              </n-scrollbar>
+            </div>
+            <ProblemDrawer v-model="drawer" to="#problem-pane-stack" />
+          </div>
+        </div>
       </template>
       <template #2>
         <ProblemEditor />
@@ -202,32 +220,61 @@ onBeforeUnmount(() => {
     </n-split>
 
     <!-- Mobile -->
-    <n-tabs v-else v-model:value="currentTab" type="segment">
-      <n-tab-pane name="content" tab="题目">
-        <ProblemContent />
-      </n-tab-pane>
-      <n-tab-pane v-if="canShowFlowchart" name="flowchart" tab="流程">
-        <ProblemFlowchart />
-      </n-tab-pane>
-      <n-tab-pane name="editor" tab="代码">
-        <ProblemEditor />
-      </n-tab-pane>
-      <n-tab-pane name="result" :tab="resultTab" display-directive="show:lazy">
-        <ResultPane />
-      </n-tab-pane>
-      <n-tab-pane name="info" tab="统计" :disabled="!!problemSetId">
-        <ProblemInfo />
-      </n-tab-pane>
-      <n-tab-pane v-if="!contestID" name="comment" tab="点评" :disabled="!!problemSetId">
-        <ProblemReaction />
-      </n-tab-pane>
-      <n-tab-pane v-if="myFlowchartStore.showing" name="my-flowchart" tab="我的流程图">
-        <MyFlowchartTab />
-      </n-tab-pane>
-      <n-tab-pane name="submission" tab="提交" :disabled="!!problemSetId">
-        <ProblemSubmission />
-      </n-tab-pane>
-    </n-tabs>
+    <template v-else>
+      <ContextBar />
+      <n-tabs v-model:value="currentTab" type="segment">
+        <n-tab-pane name="content" tab="题目">
+          <ProblemContent />
+        </n-tab-pane>
+        <n-tab-pane name="editor" tab="代码">
+          <ProblemEditor />
+        </n-tab-pane>
+        <n-tab-pane name="result" :tab="resultTab" display-directive="show:lazy">
+          <ResultPane />
+        </n-tab-pane>
+        <template v-if="drawerMenu.length" #suffix>
+          <n-dropdown trigger="click" :options="drawerMenu" @select="toggleDrawer">
+            <n-button size="small" quaternary aria-label="统计、点评、我的提交"> ⋯ </n-button>
+          </n-dropdown>
+        </template>
+      </n-tabs>
+      <ProblemDrawer v-model="drawer" />
+    </template>
   </template>
   <n-empty v-else :description="errMsg"></n-empty>
 </template>
+
+<style scoped>
+.left-pane {
+  position: relative;
+  height: 100%;
+  display: flex;
+  flex-direction: column;
+  overflow: hidden;
+}
+
+.tab-row {
+  flex: none;
+  height: 42px;
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 12px;
+}
+
+.page-tabs {
+  width: 180px;
+  flex: none;
+}
+
+.pane-stack {
+  position: relative;
+  flex: 1;
+  min-height: 0;
+  overflow: hidden;
+}
+
+.pane-body {
+  height: 100%;
+}
+</style>
diff --git a/apps/web/src/oj/store/contest.ts b/apps/web/src/oj/store/contest.ts
index 6951312..1c700e6 100644
--- a/apps/web/src/oj/store/contest.ts
+++ b/apps/web/src/oj/store/contest.ts
@@ -2,7 +2,7 @@ import { errorCode } from "utils/api"
 import { formatISO, getTime, parseISO } from "date-fns"
 import { useUserStore } from "shared/store/user"
 import { ContestStatus, ContestType } from "utils/constants"
-import { duration } from "utils/functions"
+import { duration, secondsToDuration } from "utils/functions"
 import type { Contest, ProblemRow } from "utils/types"
 import { checkContestPassword, getContest, getContestAccess, getContestProblems } from "../api"
 
@@ -40,6 +40,14 @@ export const useContestStore = defineStore("contest", () => {
     }
   })
 
+  /** 进行中还剩多久，「38:12」「1:05:00」这种；不在进行中为空串。题目页上下文条用 */
+  const remaining = computed(() => {
+    if (contestStatus.value !== ContestStatus.underway) return ""
+    const end = getTime(parseISO(contest.value!.endTime.toString()))
+    const text = secondsToDuration(Math.max(0, Math.floor((end - now.value) / 1000)))
+    return text.startsWith("0:") ? text.slice(2) : text
+  })
+
   const isContestAdmin = computed(
     () =>
       userStore.isSuperAdmin ||
@@ -112,6 +120,7 @@ export const useContestStore = defineStore("contest", () => {
     problems,
     isPrivate,
     countdown,
+    remaining,
     init,
     clear,
     checkPassword,
diff --git a/apps/web/src/oj/store/lesson.ts b/apps/web/src/oj/store/lesson.ts
new file mode 100644
index 0000000..0b2ea45
--- /dev/null
+++ b/apps/web/src/oj/store/lesson.ts
@@ -0,0 +1,58 @@
+import { defineStore } from "pinia"
+import { getClassActivity } from "oj/api"
+import type { ClassActivity, ClassActivityProblem } from "utils/types"
+
+/** 同一节课里来回换题不用每次都重拉；过了这么久再进题目页就重拉一次 */
+const STALE_MS = 2 * 60 * 1000
+
+/**
+ * 「这节课的题」：首页「班里在做」那几道（老师在课堂看板布置的，或者从同班提交推断的）。
+ *
+ * 题目页有两处要用：顶部的课堂条（做完几道、每道的状态），和通过之后的「下一题」。
+ * 原来「下一题」每次通过都自己拉一遍，现在两处读同一份，通过之后由判题那边
+ * （SubmissionEffects）先把这道就地标成做完、再重拉一次。
+ */
+export const useLessonStore = defineStore("lesson", () => {
+  const activity = ref<ClassActivity | null>(null)
+  let loadedAt = 0
+  let loading: Promise<void> | null = null
+
+  /** 没拉过或者旧了才拉；force 用在刚通过一道题之后 */
+  function load(force = false) {
+    if (!force && activity.value && Date.now() - loadedAt < STALE_MS) return loading
+    loading = getClassActivity()
+      .then((res) => {
+        activity.value = res
+        loadedAt = Date.now()
+      })
+      // 拉不到就没有课堂条，不影响做题
+      .catch(() => {})
+      .finally(() => {
+        loading = null
+      })
+    return loading
+  }
+
+  /** 刚通过：不等重拉，先把这道标成做完，课堂条上的「做完 N/M」马上加一 */
+  function markAccepted(problemDisplayId: string) {
+    const item = find(problemDisplayId)
+    if (item) item.myStatus = "accepted"
+  }
+
+  function find(problemDisplayId: string): ClassActivityProblem | undefined {
+    const id = problemDisplayId.toLowerCase()
+    return activity.value?.problems.find((item) => item.problemDisplayId.toLowerCase() === id)
+  }
+
+  /** 这道题在不在这节课里；不在（学生在做别的）就没有课堂条、也没有「下一题」 */
+  function includes(problemDisplayId: string) {
+    return !!find(problemDisplayId)
+  }
+
+  /** 老师布置的叫「老师布置的题」，推断出来的叫「这节课的题」 */
+  const label = computed(() =>
+    activity.value?.source === "teacher" ? "老师布置的题" : "这节课的题",
+  )
+
+  return { activity, label, load, markAccepted, includes }
+})
diff --git a/docs/specs/2026-09-28-problem-page-redesign-design.md b/docs/specs/2026-09-28-problem-page-redesign-design.md
index 3be3f6c..a8aa3d9 100644
--- a/docs/specs/2026-09-28-problem-page-redesign-design.md
+++ b/docs/specs/2026-09-28-problem-page-redesign-design.md
@@ -1,7 +1,7 @@
 # OJ2 设计文档：题目详情页重设计
 
 日期：2026-09-28
-状态：**设计已定，未实施**。效果图在 claude.ai 的私有画布「题目详情页重设计」里（「机房（方案 B）」
+状态：**设计已定，第 14 节的 1–4 步已实施**（还没做：5.5 的「我的提交」行内展开与「放回编辑器」、5.2 的例子表格、第 7 节的点评文案与防误触）。效果图在 claude.ai 的私有画布「题目详情页重设计」里（「机房（方案 B）」
 那一页是定稿，「初稿 1280×800」那一页已作废，只留着对照）。效果图表达不了的规则都写在这里，
 **实施时以本文为准**。