diff --git a/apps/web/CLAUDE.md b/apps/web/CLAUDE.md
index cfb8178..31e5860 100644
--- a/apps/web/CLAUDE.md
+++ b/apps/web/CLAUDE.md
@@ -59,7 +59,7 @@ API 调用不按模块分：学生端全在 `oj/api.ts`、后台全在 `admin/ap
 
 Shared logic lives in `shared/`:
 - `store/` — Pinia stores: `user` (auth/roles), `config` (site-wide settings), `authModal` (login/signup form state), `loginSummary` (AI activity summary), `collab` (help-request queue + collab room), `achievement` (解锁弹窗队列), `myFlowchart` (题面「你画的流程图」那张 A/S 图的 mermaid 源码)
-- `composables/` — `aiStream`, `pagination` (URL-synced), `websocket` (reconnect + heartbeat), `collabDoc` (Yjs binding for the collab channel), `configUpdate` (WS-pushed config sync), `useMermaid` (lazy Mermaid render), `darkTransition` (View Transitions，111 以下走降级分支), `hiddenStudents` (统计面板的「请假隐藏」), `chartTheme`, `breakpoints`, `maxkb`, `learnProgress`, `rarity`
+- `composables/` — `aiStream`, `pagination` (URL-synced), `websocket` (reconnect + heartbeat), `collabDoc` (Yjs binding for the collab channel), `configUpdate` (WS-pushed config sync), `useMermaid` (lazy Mermaid render), `darkTransition` (View Transitions，111 以下走降级分支), `hiddenStudents` (课堂看板的「请假隐藏」), `chartTheme`, `breakpoints`, `maxkb`, `learnProgress`, `rarity`
 - `layout/` — `default.vue` and `admin.vue` layout wrappers
 - `api.ts` — shared API calls (auth, profile, tags, captcha)
 
diff --git a/apps/web/src/admin/contest/helper.vue b/apps/web/src/admin/contest/helper.vue
index 7fa9fd8..cfce653 100644
--- a/apps/web/src/admin/contest/helper.vue
+++ b/apps/web/src/admin/contest/helper.vue
@@ -282,7 +282,6 @@ onMounted(loadData)
       <SubmissionDetail
         v-if="currentSubmission"
         :submission="currentSubmission"
-        :problemID="currentSubmission.problemDisplayId"
         :submissionID="currentSubmission.id"
         hideList
         @copied="toggleCodePanel(false)"
diff --git a/apps/web/src/oj/api.ts b/apps/web/src/oj/api.ts
index bcfb611..9ee7c1b 100644
--- a/apps/web/src/oj/api.ts
+++ b/apps/web/src/oj/api.ts
@@ -39,7 +39,6 @@ import {
   type UserBadge,
   type FlowchartStatistics,
   type SubmissionStatistics,
-  type SubmissionStatisticsItems,
   type SubmissionStatisticsGrid,
   type TodaySubmissionStatistics,
 } from "@oj2/contract"
@@ -174,27 +173,15 @@ export function adminRejudge(id: string) {
   return api.post<{ ok: boolean }>(`submissions/${encodeURIComponent(id)}/rejudge`)
 }
 
-/**
- * 统计面板展开一行时拉这个人的明细。username 这里要**精确**到人，
- * 和上面那个按班级模糊匹配的不是一回事。
- */
-export function getSubmissionStatisticsItems(
-  duration: { start?: string; end: string },
-  username: string,
-  problemDisplayId?: string,
-) {
-  return api.get<SubmissionStatisticsItems>("submissions/statistics/items", {
-    params: { ...duration, problemDisplayId, username },
-  })
-}
-
 export function getSubmissionStatistics(
   duration: { start?: string; end: string },
   problemDisplayId?: string,
   username?: string,
+  /** 班级（user.class_name）精确匹配。别再拼 `ks231` 塞进 username —— 会连带 2311、2312 班 */
+  className?: string,
 ) {
   return api.get<SubmissionStatistics>("submissions/statistics", {
-    params: { ...duration, problemDisplayId, username },
+    params: { ...duration, problemDisplayId, username, className },
   })
 }
 
@@ -203,9 +190,10 @@ export function getSubmissionStatisticsGrid(
   duration: { start?: string; end: string },
   problemDisplayId?: string,
   username?: string,
+  className?: string,
 ) {
   return api.get<SubmissionStatisticsGrid>("submissions/statistics/grid", {
-    params: { ...duration, problemDisplayId, username },
+    params: { ...duration, problemDisplayId, username, className },
   })
 }
 
@@ -430,6 +418,8 @@ export function getFlowchartSubmission(id: string) {
 
 export function getFlowchartSubmissions(params: {
   username?: string
+  /** "1" = username 整名匹配，同代码提交列表 */
+  exactUsername?: "1"
   className?: string
   problemDisplayId?: string
   myself?: string
@@ -445,9 +435,10 @@ export function getFlowchartStatistics(
   duration: { start?: string; end: string },
   problemDisplayId?: string,
   username?: string,
+  className?: string,
 ) {
   return api.get<FlowchartStatistics>("flowcharts/statistics", {
-    params: { ...duration, problemDisplayId, username },
+    params: { ...duration, problemDisplayId, username, className },
   })
 }
 
diff --git a/apps/web/src/oj/classroom/board.vue b/apps/web/src/oj/classroom/board.vue
index de2b1e5..7767c7a 100644
--- a/apps/web/src/oj/classroom/board.vue
+++ b/apps/web/src/oj/classroom/board.vue
@@ -142,12 +142,19 @@ function nameOf(student: ClassBoardStudent) {
  * 请假隐藏（原来在「数据统计」弹框里，统计改成回头看之后挪到这儿 —— 盯这节课的是看板）。
  * 请假、转班、学号错了的那几个一直挂在「还没交过」里，会盖住真正要去看的人。
  * 藏两个小时（够一节课），下节课自动回来；只记在这台电脑上，换人换机器都不继承。
- * 键沿用统计弹框那份，老师上午藏的人这里接着藏着
+ * 键沿用统计弹框那份，老师上午藏的人这里接着藏着。
+ *
+ * **只藏「还没交过」的人**：一个学生只要今天交过、或者正在举手，就不算请假，照常显示、
+ * 照常算进人数。迟到的学生后来交了题、卡住了、举手了，老师得看得见
  */
-const { hideMode, hideStudent, showAll, isHidden } = useHiddenStudents("oj_hidden_students")
-const hiddenStudents = computed(() =>
-  (board.value?.students ?? []).filter((student) => isHidden(student.username)),
-)
+const { hideMode, hideStudent, unhide, isHidden } = useHiddenStudents("oj_hidden_students")
+function hiddenNow(student: ClassBoardStudent) {
+  return !student.lastSubmitAt && !helpOf(student) && isHidden(student.username)
+}
+const hiddenStudents = computed(() => (board.value?.students ?? []).filter(hiddenNow))
+function restoreHidden() {
+  unhide(hiddenStudents.value.map((student) => student.username))
+}
 
 const students = computed(() =>
   [...(board.value?.students ?? [])]
@@ -328,7 +335,7 @@ function submissionsHref(student: ClassBoardStudent, problemDisplayId?: string)
           <n-alert
             v-if="idle.length || hiddenStudents.length"
             type="warning"
-            :title="`今天还没交过（${idle.length} 人）`"
+            :title="idle.length ? `今天还没交过（${idle.length} 人）` : '今天没交过的都隐藏了'"
             class="section"
           >
             <n-flex align="center" :size="10" class="hide-bar">
@@ -341,7 +348,7 @@ function submissionsHref(student: ClassBoardStudent, problemDisplayId?: string)
                 size="tiny"
                 text
                 type="primary"
-                @click="showAll"
+                @click="restoreHidden"
               >
                 隐藏了 {{ hiddenStudents.length }} 位：{{ hiddenStudents.map(nameOf).join("、") }} ·
                 恢复
diff --git a/apps/web/src/oj/statistics/components/AttemptSquares.vue b/apps/web/src/oj/statistics/components/AttemptSquares.vue
index c79fabb..8533c25 100644
--- a/apps/web/src/oj/statistics/components/AttemptSquares.vue
+++ b/apps/web/src/oj/statistics/components/AttemptSquares.vue
@@ -9,6 +9,7 @@ const codeCache = new Map<string, Submission>()
 </script>
 
 <script setup lang="ts">
+import { useThemeVars } from "naive-ui"
 import { getSubmission } from "oj/api"
 import { JUDGE_STATUS, LANGUAGE_FORMAT_VALUE, SubmissionStatus } from "utils/constants"
 import { parseTime } from "utils/functions"
@@ -28,6 +29,7 @@ const props = withDefaults(
 )
 
 const tone = useTone()
+const theme = useThemeVars()
 
 function toneOf(result: number): Tone {
   if (result === SubmissionStatus.accepted) return "success"
@@ -131,7 +133,8 @@ const cells = computed(() =>
 }
 
 .square:hover {
-  outline: 2px solid currentColor;
+  /* button 的 color 是浏览器默认的黑，暗色下 currentColor 描边会看不见 */
+  outline: 2px solid v-bind("theme.textColor2");
   outline-offset: 1px;
 }
 
diff --git a/apps/web/src/oj/statistics/components/ByClass.vue b/apps/web/src/oj/statistics/components/ByClass.vue
index 1dd041f..4f9522e 100644
--- a/apps/web/src/oj/statistics/components/ByClass.vue
+++ b/apps/web/src/oj/statistics/components/ByClass.vue
@@ -9,7 +9,11 @@ import { classLabel, submissionDayText } from "oj/submission/utils"
  * 没选班级、也没填学生时（多半是从题目页进来，只带了题号）：先按班级列出来，
  * 点一个班再看人。「一道没交」要花名册人数，后端在这种情况下给 classSizes。
  */
-const props = defineProps<{ grid: SubmissionStatisticsGrid }>()
+const props = defineProps<{
+  grid: SubmissionStatisticsGrid
+  /** 题号是老师填的。没填时「做完」没法谈（范围里各班各做各的题），改成「做对过题」 */
+  explicit: boolean
+}>()
 const emit = defineEmits<{ pick: [className: string] }>()
 
 const theme = useThemeVars()
@@ -36,8 +40,12 @@ const classes = computed(() => {
         const solved = new Set(
           row.submissions.filter((item) => isAc(item.result)).map((item) => item.problemDisplayId),
         )
-        if (need.every((pid) => solved.has(pid))) done++
-        submissions += row.submissions.length
+        if (props.explicit ? need.every((pid) => solved.has(pid)) : solved.size > 0) done++
+        // 正确率的分母不算还在判的，和数字行一个口径
+        submissions += row.submissions.filter(
+          (item) =>
+            item.result !== SubmissionStatus.pending && item.result !== SubmissionStatus.judging,
+        ).length
         accepted += row.submissions.filter((item) => isAc(item.result)).length
         const lastTime = row.submissions.at(-1)?.createTime ?? ""
         if (lastTime > last) last = lastTime
@@ -62,8 +70,8 @@ const classes = computed(() => {
   <div class="by-class">
     <div class="cols">
       <span class="c-class">班级</span>
-      <span class="c-done">做完</span>
-      <span class="c-n">交了没对</span>
+      <span class="c-done">{{ explicit ? "做完" : "做对过题" }}</span>
+      <span class="c-n">{{ explicit ? "交了没对" : "一道没对" }}</span>
       <span class="c-n">没交</span>
       <span class="c-n">正确率</span>
       <span class="c-last">最近一次</span>
@@ -97,6 +105,9 @@ const classes = computed(() => {
         </n-button>
       </div>
       <div v-if="!classes.length" class="empty">这段时间没有人交</div>
+      <p v-if="grid.truncated" class="note warn" :style="{ color: tone('warning').color }">
+        范围太大，只取了最近的 5000 条提交，更早的班级可能少算或不在表里。缩短时间段就准了。
+      </p>
       <p class="note">没选班级，先按班级列出来；点一个班再看每个人。「做完」是这几道题都做对了。</p>
     </div>
   </div>
@@ -201,4 +212,22 @@ const classes = computed(() => {
   font-size: 12px;
   color: v-bind("theme.textColor3");
 }
+
+/* 手机：这张表列多，横着滑 */
+@media (max-width: 767px) {
+  .by-class {
+    flex: none;
+    overflow-x: auto;
+  }
+
+  .cols,
+  .row {
+    min-width: 820px;
+  }
+
+  .rows {
+    flex: none;
+    overflow: visible;
+  }
+}
 </style>
diff --git a/apps/web/src/oj/statistics/components/CodeStats.vue b/apps/web/src/oj/statistics/components/CodeStats.vue
index 78311bd..f5efc45 100644
--- a/apps/web/src/oj/statistics/components/CodeStats.vue
+++ b/apps/web/src/oj/statistics/components/CodeStats.vue
@@ -18,10 +18,17 @@ import AttemptSquares from "./AttemptSquares.vue"
 const props = defineProps<{
   stats: SubmissionStatistics
   grid: SubmissionStatisticsGrid
+  /**
+   * 题号是老师填的（true），还是没填、从范围里出现过的题凑出来的（false）。没填时一个月
+   * 零零散散几十道题谈不上「全做完」，「做完」改成「做对过题」（做对至少一道），和数字行一致
+   */
+  explicit: boolean
 }>()
 
 const theme = useThemeVars()
 const tone = useTone()
+// 暗色下「做对了」那格的底色是浅绿，白字看不清
+const isDark = useDark()
 
 type Attempt = SubmissionStatisticsGrid["rows"][number]["submissions"][number]
 
@@ -29,6 +36,10 @@ function isAc(result: number) {
   return result === SubmissionStatus.accepted || result === SubmissionStatus.ast_check_failed
 }
 
+function isPending(result: number) {
+  return result === SubmissionStatus.pending || result === SubmissionStatus.judging
+}
+
 interface Student {
   username: string
   name: string
@@ -36,6 +47,8 @@ interface Student {
   byProblem: Map<string, Attempt[]>
   total: number
   accepted: number
+  /** 判完的条数，正确率的分母（和数字行一个口径：还在判的不算） */
+  judged: number
   last: string | null
 }
 
@@ -54,6 +67,7 @@ const students = computed<Student[]>(() => {
       byProblem,
       total: row.submissions.length,
       accepted: row.submissions.filter((item) => isAc(item.result)).length,
+      judged: row.submissions.filter((item) => !isPending(item.result)).length,
       last: row.submissions.at(-1)?.createTime ?? null,
     }
   })
@@ -66,6 +80,7 @@ const students = computed<Student[]>(() => {
       byProblem: new Map(),
       total: 0,
       accepted: 0,
+      judged: 0,
       last: null,
     })
   }
@@ -79,6 +94,18 @@ function solvedOn(student: Student, pid: string) {
   return (student.byProblem.get(pid) ?? []).some((item) => isAc(item.result))
 }
 
+/**
+ * 答案对了、但「语法未通过」（AST 规则没按要求写），而且没有一次真正的「答案正确」。
+ * 这类算做对了（全站口径），但教学上没达标，格子上单独标出来
+ */
+function astOnlyOn(student: Student, pid: string) {
+  const items = student.byProblem.get(pid) ?? []
+  return (
+    items.some((item) => item.result === SubmissionStatus.ast_check_failed) &&
+    !items.some((item) => item.result === SubmissionStatus.accepted)
+  )
+}
+
 function doneCount(student: Student) {
   return problems.value.filter((problem) => solvedOn(student, problem.problemDisplayId)).length
 }
@@ -98,9 +125,14 @@ const problemRows = computed(() =>
   }),
 )
 
-const allDone = computed(
-  () => students.value.filter((student) => doneCount(student) === problems.value.length).length,
-)
+/** 算「做完」要做对几道：填了题号就要全对，没填就是做对过题 */
+const needed = computed(() => (props.explicit ? problems.value.length : 1))
+function finished(student: Student) {
+  return problems.value.length > 0 && doneCount(student) >= needed.value
+}
+const doneLabel = computed(() => (props.explicit ? "做完" : "做对过题"))
+
+const allDone = computed(() => students.value.filter(finished).length)
 
 // ---------- 选中哪道题、筛哪些人 ----------
 
@@ -142,11 +174,16 @@ const problemStudents = computed(() => {
 
 /** 全部题：没做完的在前（交得多的更前），一道没交的其次，全做完的沉底 */
 const allStudents = computed(() => {
-  const n = problems.value.length
-  const list = students.value.map((student) => ({ student, done: doneCount(student) }))
-  const rank = (row: (typeof list)[number]) => (row.done === n ? 2 : row.student.total ? 0 : 1)
+  // 这段时间没人交：没有题可言，别列一排「0 道」
+  if (!problems.value.length) return []
+  const list = students.value.map((student) => ({
+    student,
+    done: doneCount(student),
+    finished: finished(student),
+  }))
+  const rank = (row: (typeof list)[number]) => (row.finished ? 2 : row.student.total ? 0 : 1)
   return list
-    .filter((row) => !onlyUnfinished.value || row.done < n)
+    .filter((row) => !onlyUnfinished.value || !row.finished)
     .sort(
       (a, b) =>
         rank(a) - rank(b) ||
@@ -158,7 +195,7 @@ const allStudents = computed(() => {
 const unfinishedCount = computed(() =>
   focus.value
     ? students.value.filter((student) => !solvedOn(student, focus.value)).length
-    : students.value.filter((student) => doneCount(student) < problems.value.length).length,
+    : students.value.filter((student) => !finished(student)).length,
 )
 
 const expanded = ref("")
@@ -182,7 +219,7 @@ function problemsOf(student: Student) {
 }
 
 function rate(student: Student) {
-  return student.total ? `${Math.round((student.accepted / student.total) * 100)}%` : "—"
+  return student.judged ? `${Math.round((student.accepted / student.judged) * 100)}%` : "—"
 }
 
 function dayText(time: string | null) {
@@ -209,7 +246,7 @@ function pct(done: number, total: number) {
           <span class="p-line">
             <b>全部 {{ problems.length }} 道</b>
             <span class="spacer"></span>
-            <span class="muted">做完 {{ allDone }}/{{ personCount }} 人</span>
+            <span class="muted">{{ doneLabel }} {{ allDone }}/{{ personCount }} 人</span>
           </span>
           <span class="bar"
             ><span class="fill" :style="{ width: pct(allDone, personCount) }"></span
@@ -247,18 +284,33 @@ function pct(done: number, total: number) {
             {{ Math.max(0, personCount - focusRow.tried) }}
           </span>
         </template>
+        <template v-else-if="!problems.length">
+          <b class="s-title">这段时间没有人交</b>
+          <span class="muted">换个时间段试试，比如「今天」或「最近 7 天」</span>
+        </template>
         <template v-else>
           <b class="s-title">全部 {{ problems.length }} 道</b>
           <span class="muted">
-            做完 {{ allDone }}/{{ personCount }} · 没做完 {{ unfinishedCount }} · 一道没交
+            {{ doneLabel }} {{ allDone }}/{{ personCount }} · 没做完 {{ unfinishedCount }} ·
+            一道没交
             {{ stats.dataUnaccepted.length }}
           </span>
         </template>
         <span class="spacer"></span>
-        <button class="chip" :class="{ on: onlyUnfinished }" @click="onlyUnfinished = true">
+        <button
+          v-if="problems.length"
+          class="chip"
+          :class="{ on: onlyUnfinished }"
+          @click="onlyUnfinished = true"
+        >
           没做完 <span class="n">{{ unfinishedCount }}</span>
         </button>
-        <button class="chip" :class="{ on: !onlyUnfinished }" @click="onlyUnfinished = false">
+        <button
+          v-if="problems.length"
+          class="chip"
+          :class="{ on: !onlyUnfinished }"
+          @click="onlyUnfinished = false"
+        >
           全部 <span class="n">{{ students.length }}</span>
         </button>
       </div>
@@ -289,7 +341,7 @@ function pct(done: number, total: number) {
 
       <!-- 全部题：每人一行，一格一道题；点开按题看方块串 -->
       <template v-else>
-        <div class="cols">
+        <div v-if="problems.length" class="cols">
           <span class="c-caret"></span>
           <span class="c-name">学生</span>
           <span class="c-done">做完</span>
@@ -302,7 +354,12 @@ function pct(done: number, total: number) {
             <div
               class="row clickable"
               :class="{ on: expanded === row.student.username }"
+              role="button"
+              tabindex="0"
+              :aria-expanded="expanded === row.student.username"
               @click="toggle(row.student.username)"
+              @keydown.enter.prevent="toggle(row.student.username)"
+              @keydown.space.prevent="toggle(row.student.username)"
             >
               <span class="c-caret">
                 <Icon
@@ -316,15 +373,14 @@ function pct(done: number, total: number) {
               <span
                 class="c-done done"
                 :style="{
-                  color:
-                    row.done === problems.length
-                      ? tone('success').color
-                      : row.student.total
-                        ? theme.textColor1
-                        : tone('error').color,
+                  color: row.finished
+                    ? tone('success').color
+                    : row.student.total
+                      ? theme.textColor1
+                      : tone('error').color,
                 }"
               >
-                {{ row.done }}/{{ problems.length }}
+                {{ explicit ? `${row.done}/${problems.length}` : `${row.done} 道` }}
               </span>
               <span class="c-n muted">{{ row.student.total }}</span>
               <span class="c-rate muted">{{ rate(row.student) }}</span>
@@ -333,19 +389,30 @@ function pct(done: number, total: number) {
                   v-for="problem in problems"
                   :key="problem.problemDisplayId"
                   class="cell"
-                  :title="problem.problemDisplayId + ' ' + problem.title"
+                  :title="
+                    problem.problemDisplayId +
+                    ' ' +
+                    problem.title +
+                    (astOnlyOn(row.student, problem.problemDisplayId)
+                      ? '：答案对了，但没按要求的写法写'
+                      : '')
+                  "
                   :style="
-                    solvedOn(row.student, problem.problemDisplayId)
-                      ? { background: tone('success').solid, color: '#fff' }
-                      : row.student.byProblem.has(problem.problemDisplayId)
-                        ? { background: tone('error').background, color: tone('error').color }
-                        : { background: theme.actionColor, color: theme.textColor3 }
+                    astOnlyOn(row.student, problem.problemDisplayId)
+                      ? { background: tone('warning').background, color: tone('warning').color }
+                      : solvedOn(row.student, problem.problemDisplayId)
+                        ? { background: tone('success').solid, color: isDark ? '#18181c' : '#fff' }
+                        : row.student.byProblem.has(problem.problemDisplayId)
+                          ? { background: tone('error').background, color: tone('error').color }
+                          : { background: theme.actionColor, color: theme.textColor3 }
                   "
                 >
                   {{
-                    solvedOn(row.student, problem.problemDisplayId)
-                      ? "✓"
-                      : (row.student.byProblem.get(problem.problemDisplayId)?.length ?? "·")
+                    astOnlyOn(row.student, problem.problemDisplayId)
+                      ? "语"
+                      : solvedOn(row.student, problem.problemDisplayId)
+                        ? "✓"
+                        : (row.student.byProblem.get(problem.problemDisplayId)?.length ?? "·")
                   }}
                 </span>
               </span>
@@ -383,11 +450,12 @@ function pct(done: number, total: number) {
               </div>
             </div>
           </template>
-          <div v-if="!allStudents.length" class="empty">全都做完了</div>
+          <div v-if="problems.length && !allStudents.length" class="empty">全都做完了</div>
         </div>
       </template>
       <div v-if="grid.truncated" class="truncated">
-        范围太大，方块串只画了最近 5000 条；上面的人数、正确率仍是全部算的。
+        范围太大，只取了最近的 5000 条提交：上面一排数字是全部算的，左边每道题的「做完」、
+        右边的名单和方块串只按这 5000 条算，更早交的人可能不在里面。缩短时间段就准了。
       </div>
     </section>
   </div>
@@ -695,4 +763,55 @@ function pct(done: number, total: number) {
   color: v-bind("tone('warning').color");
   border-top: 1px solid v-bind("theme.dividerColor");
 }
+
+/* 手机：题目在上、学生在下，整页滚动 */
+@media (max-width: 767px) {
+  .code-stats {
+    flex-direction: column;
+    flex: none;
+  }
+
+  .problems {
+    width: 100%;
+    border-right: 0;
+    border-bottom: 1px solid v-bind("theme.dividerColor");
+  }
+
+  .problem-list,
+  .rows {
+    flex: none;
+    overflow: visible;
+  }
+
+  .s-head {
+    height: auto;
+    flex-wrap: wrap;
+    padding: 8px 14px;
+    row-gap: 6px;
+    white-space: normal;
+  }
+
+  .cols {
+    display: none;
+  }
+
+  .row {
+    flex-wrap: wrap;
+    padding: 8px 14px;
+    row-gap: 6px;
+  }
+
+  .c-seq,
+  .c-grid {
+    flex-basis: 100%;
+  }
+
+  .c-when {
+    display: none;
+  }
+
+  .detail {
+    padding-left: 14px;
+  }
+}
 </style>
diff --git a/apps/web/src/oj/statistics/components/FlowStats.vue b/apps/web/src/oj/statistics/components/FlowStats.vue
index 4ba0d45..d9c831c 100644
--- a/apps/web/src/oj/statistics/components/FlowStats.vue
+++ b/apps/web/src/oj/statistics/components/FlowStats.vue
@@ -56,9 +56,11 @@ const gradeColor = computed(() => ({
 }))
 
 /** 拿到 A / S 算完成（和题单、课堂条的口径一致） */
-const goodCount = computed(
-  () => props.data.people.filter((row) => row.bestGrade === "S" || row.bestGrade === "A").length,
-)
+const goodCount = computed(() => {
+  // 查几道题就要每道都拿到 A / S；没填题号时拿到一道就算
+  const need = Math.max(1, props.data.problemCount)
+  return props.data.people.filter((row) => row.goodProblems >= need).length
+})
 const personCount = computed(() => props.data.personCount || props.data.people.length)
 
 const gradeData = computed(() => ({
@@ -285,6 +287,7 @@ function gradeStyle(grade: string | null) {
         </div>
         <div class="card people">
           <div class="card-title">每人最好的一次（没交的在前）</div>
+          <div v-if="data.peopleTruncated" class="muted">人太多，只列了成绩靠后的 500 位</div>
           <div class="people-list">
             <div v-for="row in people" :key="row.username" class="person">
               <b class="p-name" :title="row.username">{{ row.name }}</b>
@@ -447,4 +450,47 @@ function gradeStyle(grade: string | null) {
   text-align: center;
   color: v-bind("theme.textColor3");
 }
+
+/* 手机：卡片一张一行 */
+@media (max-width: 767px) {
+  .flow-stats {
+    flex: none;
+  }
+
+  .summary {
+    height: auto;
+    flex-wrap: wrap;
+    gap: 12px 24px;
+    padding: 10px 14px;
+  }
+
+  .body {
+    flex: none;
+    overflow: visible;
+    padding: 12px 14px;
+  }
+
+  .row-cards,
+  .row-cards.bottom {
+    flex-direction: column;
+    height: auto;
+  }
+
+  .card.grade,
+  .card.radar,
+  .card.people {
+    width: 100%;
+  }
+
+  .card .chart,
+  .card .cloud {
+    flex: none;
+    height: 240px;
+  }
+
+  .card.people .people-list {
+    flex: none;
+    max-height: 360px;
+  }
+}
 </style>
diff --git a/apps/web/src/oj/statistics/index.vue b/apps/web/src/oj/statistics/index.vue
index 097d9ab..48210f0 100644
--- a/apps/web/src/oj/statistics/index.vue
+++ b/apps/web/src/oj/statistics/index.vue
@@ -36,7 +36,6 @@ const router = useRouter()
 const configStore = useConfigStore()
 const theme = useThemeVars()
 const tone = useTone()
-const message = useMessage()
 
 const tab = useRouteQuery<string>("tab", "code", { mode: "replace" })
 const className = useRouteQuery<string>("className", "", { mode: "replace" })
@@ -52,9 +51,12 @@ const periodValue = computed<Period>(() =>
     : DEFAULT_PERIOD,
 )
 
-const custom = computed<[number, number] | null>(() =>
-  from.value && to.value ? [Number(from.value), Number(to.value)] : null,
-)
+/** 地址栏里的 from / to 是手改过、不是数字的话当没选（不然 toISOString 抛错整页空白） */
+const custom = computed<[number, number] | null>(() => {
+  const a = Number(from.value)
+  const b = Number(to.value)
+  return from.value && to.value && Number.isFinite(a) && Number.isFinite(b) ? [a, b] : null
+})
 
 /** n-date-picker 按浏览器时区渲染，存取都要平移到东八区（见 utils/functions 的注释） */
 const pickerValue = computed<[number, number] | null>(() =>
@@ -70,22 +72,8 @@ function pickDates(value: [number, number] | null) {
   to.value = String(fromPickerValue(value[1]))
 }
 
-/**
- * 统计接口的「用户名」是 ilike：填 `ks253` 圈一个班。选了班级又填了学生时按学生查，
- * 学生名字不带班级前缀的话补上，免得别的班重名的混进来
- */
-const usernameParam = computed(() => {
-  const name = username.value.trim()
-  if (name) {
-    return className.value && !name.toLowerCase().startsWith("ks")
-      ? `ks${className.value}${name}`
-      : name
-  }
-  return className.value ? `ks${className.value}` : ""
-})
-
-/** 没选班级、没填学生：先按班级汇总（多半是从题目页进来的） */
-const byClass = computed(() => !usernameParam.value)
+/** 学生框：包含匹配。班级另外单独传（按 class_name 精确匹配，见后端 scopedUsers） */
+const studentParam = computed(() => username.value.trim())
 
 const classOptions = computed(() => {
   const list = configStore.config?.classList ?? []
@@ -96,42 +84,64 @@ const classOptions = computed(() => {
 // ---------- 取数 ----------
 
 const loading = ref(false)
-const failed = ref(false)
+const failed = ref("")
 const stats = ref<SubmissionStatistics | null>(null)
 const grid = ref<SubmissionStatisticsGrid | null>(null)
 const flow = ref<FlowchartStatistics | null>(null)
-const rangeText = ref("")
-const withinToday = ref(false)
+
+/**
+ * 这一份数据是按什么条件查出来的。页面上的标签（按班级汇总还是看人、「做完」还是
+ * 「做对过题」、时间范围那句话）跟着它走，不跟着输入框 —— 老师边打字边看时，数据还是
+ * 上一次的，标签先变了就对不上
+ */
+const shown = ref({ byClass: true, explicit: false, rangeText: "", withinToday: false })
 let seq = 0
 
+const ERROR_TEXT: Record<string, string> = {
+  "problem-not-found": "有题号找不到，检查一下是不是打错了",
+  "invalid-request": "一次最多查 20 道题",
+}
+
 async function load() {
   const current = ++seq
   const range = periodRange(periodValue.value, custom.value)
-  rangeText.value = range.text
-  withinToday.value = range.withinToday
   const duration = { start: range.start, end: range.end }
+  const snapshot = {
+    byClass: !studentParam.value && !className.value,
+    explicit: !!problem.value.trim(),
+    rangeText: range.text,
+    withinToday: range.withinToday,
+  }
   loading.value = true
-  failed.value = false
+  failed.value = ""
   try {
     if (tab.value === "flow") {
-      const res = await getFlowchartStatistics(duration, problem.value, usernameParam.value)
+      const res = await getFlowchartStatistics(
+        duration,
+        problem.value,
+        studentParam.value,
+        className.value,
+      )
       if (current !== seq) return
       flow.value = res
     } else {
       const [s, g] = await Promise.all([
-        getSubmissionStatistics(duration, problem.value, usernameParam.value),
-        getSubmissionStatisticsGrid(duration, problem.value, usernameParam.value),
+        getSubmissionStatistics(duration, problem.value, studentParam.value, className.value),
+        getSubmissionStatisticsGrid(duration, problem.value, studentParam.value, className.value),
       ])
       if (current !== seq) return
       stats.value = s
       grid.value = g
     }
+    shown.value = snapshot
   } catch (error) {
     if (current !== seq) return
-    failed.value = true
-    // 题号打错是最常见的：后端 404 problem-not-found
-    const code = (error as { error?: string })?.error
-    if (code === "problem-not-found") message.warning("有题号找不到，检查一下是不是打错了")
+    // 失败了就别留着上一次的结果配这一次的条件 —— 清掉，说清楚为什么
+    stats.value = null
+    grid.value = null
+    flow.value = null
+    const code = (error as { error?: string })?.error ?? ""
+    failed.value = ERROR_TEXT[code] ?? "没拉下来，改一下条件再试"
   } finally {
     if (current === seq) loading.value = false
   }
@@ -146,9 +156,9 @@ watchDebounced([username, problem], load, { debounce: 600, maxWait: 1500 })
 const doneCount = computed(() => stats.value?.data.filter((row) => row.done).length ?? 0)
 /**
  * 没填题号时后端的「做完」是「至少做对一道」—— 一个月里零零散散几十道题，谈不上
- * 「全做完」。这时这一格叫「做对过题」，别和左边「全部 N 道 · 做完 0 人」打架
+ * 「全做完」。这时各处都叫「做对过题」（CodeStats、ByClass 同一个口径）
  */
-const hasProblems = computed(() => !!problem.value.trim())
+const hasProblems = computed(() => shown.value.explicit)
 const personCount = computed(() => stats.value?.personCount ?? 0)
 const judged = computed(() =>
   stats.value ? stats.value.submissionCount - stats.value.judgingCount : 0,
@@ -164,10 +174,10 @@ function openList() {
     name: "submissions",
     query: {
       ...(tab.value === "flow" ? { language: "Flowchart" } : {}),
-      ...(className.value && !username.value ? { className: className.value } : {}),
-      ...(username.value ? { username: usernameParam.value } : {}),
+      ...(className.value ? { className: className.value } : {}),
+      ...(studentParam.value ? { username: studentParam.value } : {}),
       ...(problem.value ? { problem: problem.value } : {}),
-      ...(withinToday.value ? { today: "1" } : {}),
+      ...(shown.value.withinToday ? { today: "1" } : {}),
     },
   }).href
   window.open(href, "_blank")
@@ -227,9 +237,12 @@ function pickClass(value: string) {
         clearable
         @update:value="pickDates"
       />
-      <span v-else class="range">{{ rangeText }}</span>
+      <span v-else class="range">{{ shown.rangeText }}</span>
       <n-spin v-if="loading" :size="14" />
-      <n-text v-if="failed" type="error" class="range">没拉下来，改一下条件再试</n-text>
+      <n-text v-if="failed" type="error" class="range">{{ failed }}</n-text>
+      <span v-if="periodValue === 'custom' && !custom" class="range"
+        >选一下开始和结束的日子，没选先按今天算</span
+      >
       <span class="spacer"></span>
       <n-button
         size="small"
@@ -256,7 +269,7 @@ function pickClass(value: string) {
         <StatItem label="提交" :value="stats.submissionCount" unit="条" />
         <StatItem
           label="正确率"
-          :value="`${Math.round(stats.correctRate)}%`"
+          :value="stats.submissionCount ? `${Math.round(stats.correctRate)}%` : '—'"
           :unit="stats.judgingCount ? `判题中 ${stats.judgingCount}` : ''"
         />
         <template v-if="personCount">
@@ -299,8 +312,8 @@ function pickClass(value: string) {
           <span class="ring-label">班级<br />完成度</span>
         </span>
       </div>
-      <ByClass v-if="byClass" :grid="grid" @pick="pickClass" />
-      <CodeStats v-else :stats="stats" :grid="grid" />
+      <ByClass v-if="shown.byClass" :grid="grid" :explicit="shown.explicit" @pick="pickClass" />
+      <CodeStats v-else :stats="stats" :grid="grid" :explicit="shown.explicit" />
     </template>
   </div>
 </template>
@@ -394,4 +407,41 @@ function pickClass(value: string) {
   line-height: 1.5;
   color: v-bind("theme.textColor3");
 }
+
+/* 手机：老师很少在手机上看统计，只保证不坏 —— 筛选和数字行折行，整页自然滚动 */
+@media (max-width: 767px) {
+  .page {
+    height: auto;
+    min-height: calc(100vh - 56px);
+  }
+
+  .filters,
+  .summary {
+    height: auto;
+    flex-wrap: wrap;
+    padding: 10px 14px;
+    row-gap: 10px;
+    white-space: normal;
+  }
+
+  .summary {
+    gap: 12px 24px;
+  }
+
+  .vsep,
+  .spacer {
+    display: none;
+  }
+
+  .w-class,
+  .w-user,
+  .w-period {
+    width: calc(50% - 4px);
+  }
+
+  .w-problem,
+  .w-dates {
+    width: 100%;
+  }
+}
 </style>
diff --git a/apps/web/src/oj/statistics/period.ts b/apps/web/src/oj/statistics/period.ts
index e1e7964..7df08a4 100644
--- a/apps/web/src/oj/statistics/period.ts
+++ b/apps/web/src/oj/statistics/period.ts
@@ -35,11 +35,15 @@ function todayStart(now: number) {
   return dayStartOf(p.year, p.month, p.day)
 }
 
-/** 这学期从哪天起：9 月到次年 2 月算秋季学期（9 月 1 日起），3 到 8 月算春季（3 月 1 日起） */
+/**
+ * 这学期从哪天起：9 月到次年 1 月算秋季学期（9 月 1 日起），2 到 8 月算春季（2 月 1 日起）。
+ * 春季不从 3 月算：2 月下旬就开学了，按 3 月 1 日算的话开学头一两周「这学期」会把整个
+ * 上学期和寒假都带进来
+ */
 function termStart(now: number) {
   const p = zonedParts(new Date(now))!
   if (p.month >= 9) return dayStartOf(p.year, 9, 1)
-  if (p.month >= 3) return dayStartOf(p.year, 3, 1)
+  if (p.month >= 2) return dayStartOf(p.year, 2, 1)
   return dayStartOf(p.year - 1, 9, 1)
 }
 
diff --git a/apps/web/src/oj/submission/components/FlowchartPane.vue b/apps/web/src/oj/submission/components/FlowchartPane.vue
index 1fc9980..a5e106a 100644
--- a/apps/web/src/oj/submission/components/FlowchartPane.vue
+++ b/apps/web/src/oj/submission/components/FlowchartPane.vue
@@ -49,29 +49,41 @@ const evaluating = computed(
     props.row.status === FlowchartSubmissionStatus.PROCESSING,
 )
 
+/**
+ * 按 id 缓存，重新评分一开始（状态回到排队 / 评分中）就把这一条扔掉。原来按「id + 状态」
+ * 缓存，评完 → 排队 → 评分中 → 评完 转一圈回来正好命中重评之前的旧评语
+ */
+let loadSeq = 0
+
 async function load() {
   const row = props.row
+  const seq = ++loadSeq
   failed.value = false
   bigOpen.value = false
+  if (evaluating.value) cache.delete(row.id)
   if (!row.showLink) {
     detail.value = null
     return
   }
-  const key = `${row.id}:${row.status}`
-  let res = cache.get(key)
-  if (!res) {
+  let res = cache.get(row.id)
+  if (!res || res.status !== row.status) {
     loading.value = true
     try {
       res = await getFlowchartSubmission(row.id)
-      if (!evaluating.value) cache.set(key, res)
+      if (seq !== loadSeq) return
+      if (!evaluating.value && res.status === props.row.status) cache.set(row.id, res)
     } catch {
-      if (props.row.id === row.id) failed.value = true
+      if (seq !== loadSeq) return
+      failed.value = true
+      // 别让上一条的图留在那儿，旁边却写着「没拉下来」
+      detail.value = null
+      if (graph.value) graph.value.innerHTML = ""
       return
     } finally {
-      if (props.row.id === row.id) loading.value = false
+      if (seq === loadSeq) loading.value = false
     }
   }
-  if (props.row.id !== row.id) return
+  if (seq !== loadSeq) return
   detail.value = res
   await nextTick()
   await renderFlowchart(graph.value, res.mermaidCode)
@@ -131,8 +143,14 @@ const canRetry = computed(
   <section class="pane" :class="{ narrow }">
     <div class="head">
       <div class="who">
-        <UserName :username="row.username" />
-        <button v-if="teacher" class="filter-pill" @click="emit('filterUser', row.username)">
+        <a
+          class="user-link"
+          :href="`/user?name=${encodeURIComponent(row.username)}`"
+          target="_blank"
+        >
+          <UserName :username="row.username" />
+        </a>
+        <button class="filter-pill" @click="emit('filterUser', row.username)">
           <Icon icon="ph:funnel-simple-bold" :width="11" />只看他
         </button>
       </div>
@@ -141,11 +159,7 @@ const canRetry = computed(
         <span class="problem-id">{{ row.problemDisplayId }}</span>
         {{ row.problemTitle }}
       </a>
-      <button
-        v-if="teacher"
-        class="filter-pill"
-        @click="emit('filterProblem', row.problemDisplayId)"
-      >
+      <button class="filter-pill" @click="emit('filterProblem', row.problemDisplayId)">
         <Icon icon="ph:funnel-simple-bold" :width="11" />只看这题
       </button>
       <div class="spacer"></div>
@@ -171,13 +185,22 @@ const canRetry = computed(
 
     <div v-if="!row.showLink" class="locked">
       <Icon icon="ph:lock-simple" :width="30" class="lock-icon" />
-      <span class="locked-title">别人画的流程图看不到</span>
+      <!-- 列表项里没有 userId，分不出是别人的还是自己被题单挡住的，文案两种都说得通 -->
+      <span class="locked-title">这张流程图看不到</span>
+      <span class="muted">别人画的看不到；自己的在题单里做完这道题就能看到。</span>
     </div>
     <div v-else class="body">
       <div class="graph-box">
-        <n-alert v-if="renderError" type="error" title="流程图画不出来">
-          {{ renderError }}
-        </n-alert>
+        <!-- mermaid 的报错是英文，学生看自己的图也会碰到：先说中文，原文折起来 -->
+        <div v-if="renderError" class="render-error">
+          <b>这张流程图画不出来</b>
+          <span class="muted">可能是画的时候有框没连上，或者文字里有特殊符号。</span>
+          <n-collapse>
+            <n-collapse-item title="原始报错" name="raw">
+              <pre class="raw">{{ renderError }}</pre>
+            </n-collapse-item>
+          </n-collapse>
+        </div>
         <div v-show="!renderError" ref="graph" class="graph"></div>
         <n-spin v-if="loading && !shown" size="small" />
         <span v-if="failed" class="muted"
@@ -277,6 +300,29 @@ const canRetry = computed(
   height: 320px;
 }
 
+.user-link {
+  display: flex;
+  min-width: 0;
+  text-decoration: none;
+}
+
+.render-error {
+  display: flex;
+  flex-direction: column;
+  gap: 6px;
+  padding: 12px;
+  align-self: stretch;
+}
+
+.raw {
+  margin: 0;
+  max-height: 140px;
+  overflow: auto;
+  font-size: 12px;
+  white-space: pre-wrap;
+  word-break: break-all;
+}
+
 .who {
   display: flex;
   align-items: center;
diff --git a/apps/web/src/oj/submission/components/SubmissionPane.vue b/apps/web/src/oj/submission/components/SubmissionPane.vue
index b4edc23..9b9f5af 100644
--- a/apps/web/src/oj/submission/components/SubmissionPane.vue
+++ b/apps/web/src/oj/submission/components/SubmissionPane.vue
@@ -30,7 +30,7 @@ import UserName from "./UserName.vue"
  */
 const props = defineProps<{
   row: SubmissionListItem
-  /** 老师那套：「只看他」「只看这题」、重新判题、逐个测试点 */
+  /** 老师那套：重新判题、逐个测试点、复制两项收进「⋯」 */
   teacher: boolean
   /** 在比赛的提交列表里（不能重判，题目链接走比赛） */
   contest: boolean
@@ -55,8 +55,9 @@ const tone = useTone()
 const { copyToCat, copyToProblem } = useCopySubmission()
 
 /**
- * 详情按「id + 结果」缓存：同一条判完之前结果会变，变了要重拉；判完的代码不会再变，
- * 老师在几行之间来回按方向键时不用每次都等网络。
+ * 详情按提交 id 缓存：判完的代码和结果不会再变，老师在几行之间来回按方向键时不用每次都等网络。
+ * 还在判的不进缓存；一条被重判（结果回到「等待评分」）就把它的缓存扔掉 —— 重判后结果
+ * 可能没变（答案错误还是答案错误），但测试点和报错是新的
  */
 const cache = new Map<string, Submission>()
 const detail = ref<Submission | null>(null)
@@ -68,30 +69,34 @@ const judging = computed(
     props.row.result === SubmissionStatus.pending || props.row.result === SubmissionStatus.judging,
 )
 
+// 每次加载一个序号：同一条先按「判题中」拉了一次、判完又拉一次时，晚回来的旧请求不能盖掉新的
+let loadSeq = 0
+
 async function load() {
   const row = props.row
+  const seq = ++loadSeq
   failed.value = false
+  if (judging.value) cache.delete(row.id)
   if (!row.showLink) {
     detail.value = null
     return
   }
-  const key = `${row.id}:${row.result}`
-  const hit = cache.get(key)
-  if (hit) {
+  const hit = cache.get(row.id)
+  if (hit && hit.result === row.result) {
     detail.value = hit
     return
   }
-  // 换行时先别清空：接口一般几十毫秒就回来，清了会闪一下白
   loading.value = true
   try {
     const res = await getSubmission(row.id)
-    if (props.row.id !== row.id) return
-    if (!judging.value) cache.set(key, res)
+    if (seq !== loadSeq) return
+    // 列表那边还在判、详情这边已经判完了（或反过来）都不缓存，等两边对上
+    if (!judging.value && res.result === props.row.result) cache.set(row.id, res)
     detail.value = res
   } catch {
-    if (props.row.id === row.id) failed.value = true
+    if (seq === loadSeq) failed.value = true
   } finally {
-    if (props.row.id === row.id) loading.value = false
+    if (seq === loadSeq) loading.value = false
   }
 }
 
@@ -222,9 +227,15 @@ function openStandalone() {
   <section class="pane" :class="{ narrow }">
     <div class="head">
       <div class="who">
-        <UserName :username="row.username" :muted="!!locked && locked !== 'problemset'" />
+        <!-- 点名字开个人主页（原来列表里的用户名就是这个链接） -->
+        <a
+          class="user-link"
+          :href="`/user?name=${encodeURIComponent(row.username)}`"
+          target="_blank"
+        >
+          <UserName :username="row.username" :muted="!!locked && locked !== 'problemset'" />
+        </a>
         <button
-          v-if="teacher"
           class="filter-pill"
           title="只看这个人的提交"
           @click="emit('filterUser', row.username)"
@@ -238,7 +249,6 @@ function openStandalone() {
         {{ row.problemTitle }}
       </a>
       <button
-        v-if="teacher"
         class="filter-pill"
         title="只看这道题的提交"
         @click="emit('filterProblem', row.problemDisplayId)"
@@ -255,12 +265,13 @@ function openStandalone() {
         题单 {{ row.problemSet.title }}
       </a>
       <div class="spacer"></div>
+      <!-- 重判不用等代码拉下来：代码拉不下来的那条，恰恰可能要重判 -->
+      <n-button v-if="canRejudge" size="small" @click="emit('rejudge', row.id)">
+        <template #icon><Icon icon="ph:arrow-clockwise" /></template>
+        重新判题
+      </n-button>
       <template v-if="shown">
         <template v-if="teacher">
-          <n-button v-if="canRejudge" size="small" @click="emit('rejudge', row.id)">
-            <template #icon><Icon icon="ph:arrow-clockwise" /></template>
-            重新判题
-          </n-button>
           <n-button
             size="small"
             quaternary
@@ -429,6 +440,16 @@ function openStandalone() {
   flex-basis: 100%;
 }
 
+.user-link {
+  display: flex;
+  min-width: 0;
+  text-decoration: none;
+}
+
+.user-link:hover :deep(.name) {
+  color: v-bind("theme.primaryColor");
+}
+
 .who {
   display: flex;
   align-items: center;
diff --git a/apps/web/src/oj/submission/detail.vue b/apps/web/src/oj/submission/detail.vue
index b9664bf..38e0af0 100644
--- a/apps/web/src/oj/submission/detail.vue
+++ b/apps/web/src/oj/submission/detail.vue
@@ -16,7 +16,6 @@ import { useCopySubmission } from "./composables/copySubmission"
 
 const props = defineProps<{
   submissionID: string
-  problemID?: string
   submission?: Submission
   hideList?: boolean
 }>()
diff --git a/apps/web/src/oj/submission/list.vue b/apps/web/src/oj/submission/list.vue
index 250c6ae..4698421 100644
--- a/apps/web/src/oj/submission/list.vue
+++ b/apps/web/src/oj/submission/list.vue
@@ -40,8 +40,7 @@ import { classLabel, submissionClockText, submissionDayText } from "./utils"
  * 完成情况在课堂看板和「数据统计」里，这页不重复造一张表。
  */
 
-// 右栏和两个统计弹框都不在关键路径上：右栏要等选中一条才有内容，弹框默认关着
-// （光 chart.js 就 197KB）
+// 右栏和今日统计弹框都不在关键路径上：右栏要等选中一条才有内容，弹框默认关着
 const SubmissionPane = defineAsyncComponent(() => import("./components/SubmissionPane.vue"))
 const FlowchartPane = defineAsyncComponent(() => import("./components/FlowchartPane.vue"))
 const TodayStatistics = defineAsyncComponent(() => import("./components/TodayStatistics.vue"))
@@ -128,6 +127,9 @@ function fetchPage() {
       limit: query.limit,
       today: query.today,
       grade: query.result,
+      ...(exactFor.value && query.username === exactFor.value
+        ? { exactUsername: "1" as const }
+        : {}),
     })
   }
   return getSubmissions({
@@ -162,7 +164,13 @@ async function listSubmissions() {
     total.value = res.total
     newCount.value = 0
     loaded.value = true
+    // 翻了页、换了条件就回到列表顶上（往回翻到上一页末尾的，settleSelection 会滚到那一条）
+    const scroller = document.querySelector(".rows")
+    if (scroller) scroller.scrollTop = 0
     settleSelection()
+  } catch {
+    // 失败了别把「落地后停在哪一头」留给下一次不相干的加载
+    if (seq === requestSeq) pendingJump = null
   } finally {
     if (seq === requestSeq) loading.value = false
   }
@@ -201,8 +209,39 @@ watch(
     if (route.name === "submissions") getTodayCount()
   },
 )
-// 登录态一变，能看哪些代码就变了（showLink 是后端逐行算的）
-watch(() => userStore.isAuthed, listSubmissions)
+// 登录态一变，能看哪些代码就变了（showLink 是后端逐行算的）。掉了登录还停在流程图上的话
+// 退回代码：流程图列表要登录才能看，而没登录时那个切换按钮不显示，会卡在一片报错里出不去
+watch(
+  () => userStore.isAuthed,
+  (authed) => {
+    if (!authed && query.language === "Flowchart") query.language = ""
+    else listSubmissions()
+  },
+)
+
+/**
+ * 地址栏整个换掉时（顶栏「提交」「我的提交」、浏览器后退），地址里没写的筛选要回到默认值。
+ * usePagination 只同步地址里**有**的键 —— 在 `?myself=1` 上点顶栏「提交」，地址已经变成
+ * `/submission`，页面却还停在「我的」
+ */
+const QUERY_DEFAULTS: Record<string, string> = {
+  username: "",
+  className: "",
+  result: "",
+  myself: "0",
+  problem: "",
+  language: "",
+  today: "0",
+}
+watch(
+  () => route.query,
+  (next) => {
+    const writable = query as unknown as Record<string, string>
+    for (const [key, value] of Object.entries(QUERY_DEFAULTS)) {
+      if (next[key] === undefined && writable[key] !== value) writable[key] = value
+    }
+  },
+)
 
 // ==================== 选中与翻阅 ====================
 
@@ -254,6 +293,8 @@ const maxPage = computed(() => Math.max(1, Math.ceil(total.value / query.limit))
 function move(step: 1 | -1) {
   // 这一页一条能看的都没有（学生看全站时常见）：不翻页，不然按一下翻一页停不下来
   if (!navigable.value.length) return
+  // 上一次跨页还没回来：按住 ↓ 或者在页尾连按两下，不然会整页跳过
+  if (loading.value || pendingJump) return
   const all = rows.value
   const start = all.findIndex((row) => row.id === selectedId.value)
   for (let i = start + step; i >= 0 && i < all.length; i += step) {
@@ -272,16 +313,21 @@ const [todayPanel, toggleTodayPanel] = useToggle(false)
 
 onKeyStroke(["ArrowUp", "ArrowDown"], (e: KeyboardEvent) => {
   if (!isDesktop.value || todayPanel.value) return
-  // 焦点在输入框、下拉框里时不抢方向键
+  // 别的控件已经处理了这次按键（下拉框自己会开菜单、换选项）
+  if (e.defaultPrevented) return
   const target = e.target as HTMLElement | null
-  if (
-    target &&
-    (target.tagName === "INPUT" ||
-      target.tagName === "TEXTAREA" ||
+  if (target) {
+    // 「代码 / 流程图」「全部 / 我的」是单选框：点过之后焦点停在上面，浏览器默认会拿方向键
+    // 切换选项 —— 老师想看下一条，结果模式被切了。单选框照常换条，下面的 preventDefault 挡掉切换
+    const radio = target.tagName === "INPUT" && (target as HTMLInputElement).type === "radio"
+    // 焦点在输入框、下拉框、弹框里时不抢方向键
+    if (
+      (!radio && (target.tagName === "INPUT" || target.tagName === "TEXTAREA")) ||
       target.isContentEditable ||
-      target.closest(".n-base-select-menu, .n-dropdown-menu, .n-modal"))
-  ) {
-    return
+      target.closest(".n-base-selection, .n-base-select-menu, .n-dropdown-menu, .n-modal")
+    ) {
+      return
+    }
   }
   if (!rows.value.length) return
   e.preventDefault()
@@ -613,6 +659,16 @@ function dayBreak(index: number) {
       <span v-if="userStore.isAuthed" class="vsep"></span>
 
       <!-- 「我的」时这节课 / 班级 / 学生都用不上：后端只看自己时本来就不认它们 -->
+      <!-- 学生界面没有班级下拉：地址里带着班级（比如从统计页、看板跳过来）就摆一个能点掉的标签，
+           不然一直被一个看不见的条件筛着 -->
+      <button
+        v-if="!teacher && query.className"
+        class="chip on"
+        title="点一下去掉班级筛选"
+        @click="query.className = ''"
+      >
+        {{ classLabel(query.className) }}<Icon icon="ph:x-bold" :width="12" />
+      </button>
       <template v-if="teacher && !inContest && !mine">
         <button
           class="lesson"
@@ -741,6 +797,12 @@ function dayBreak(index: number) {
         size="small"
         :options="flowMode ? gradeOptions : resultOptions"
       />
+      <n-select
+        v-if="!inContest && !flowMode"
+        v-model:value="query.language"
+        size="small"
+        :options="languageOptions"
+      />
       <n-flex align="center">
         <button v-if="!inContest" class="chip" :class="{ on: today }" @click="today = !today">
           <Icon v-if="today" icon="ph:check-bold" :width="12" />今天
@@ -762,18 +824,39 @@ function dayBreak(index: number) {
               <div v-if="dayBreak(index)" class="day">{{ dayBreak(index) }}</div>
               <div
                 class="row"
-                :class="{ on: row.id === selectedId && !isMobile }"
+                :class="{ on: row.id === selectedId && !isMobile, mobile: isMobile }"
                 :data-row-id="row.id"
                 @click="rowClicked(row)"
               >
-                <span class="c-time">{{ submissionClockText(row.createTime) }}</span>
-                <span class="c-user"><UserName :username="row.username" /></span>
-                <span class="c-problem">
-                  <span class="pid">{{ row.problemDisplayId }}</span> {{ row.problemTitle }}
-                </span>
-                <span class="c-state">
-                  <FlowchartState :status="row.status" :grade="row.aiGrade" :score="row.aiScore" />
-                </span>
+                <template v-if="isDesktop">
+                  <span class="c-time">{{ submissionClockText(row.createTime) }}</span>
+                  <span class="c-user"><UserName :username="row.username" /></span>
+                  <span class="c-problem">
+                    <span class="pid">{{ row.problemDisplayId }}</span> {{ row.problemTitle }}
+                  </span>
+                  <span class="c-state">
+                    <FlowchartState
+                      :status="row.status"
+                      :grade="row.aiGrade"
+                      :score="row.aiScore"
+                    />
+                  </span>
+                </template>
+                <template v-else>
+                  <div class="m-line">
+                    <UserName :username="row.username" />
+                    <div class="spacer"></div>
+                    <FlowchartState
+                      :status="row.status"
+                      :grade="row.aiGrade"
+                      :score="row.aiScore"
+                    />
+                  </div>
+                  <div class="m-line sub">
+                    <span>{{ submissionClockText(row.createTime) }}</span>
+                    <span class="title">{{ row.problemDisplayId }} {{ row.problemTitle }}</span>
+                  </div>
+                </template>
               </div>
             </template>
           </template>
@@ -815,12 +898,14 @@ function dayBreak(index: number) {
                   </span>
                   <span class="c-state"><StatusPill :result="row.result" /></span>
                   <span v-if="!teacher" class="c-lock">
-                    <Icon
+                    <!-- title 放在外层 span：挂在 svg 上 Chrome 不出提示 -->
+                    <span
                       v-if="!row.showLink"
-                      icon="ph:lock-simple"
-                      :width="13"
+                      class="lock-hint"
                       :title="othersRow(row) ? '别人的代码看不到' : '在题单里做完才能看'"
-                    />
+                    >
+                      <Icon icon="ph:lock-simple" :width="13" />
+                    </span>
                   </span>
                 </template>
                 <template v-else>
@@ -905,19 +990,25 @@ function dayBreak(index: number) {
         <FlowchartPane
           v-if="flowMode"
           :row="selectedRow as FlowchartSubmissionListItem"
-          :teacher="false"
+          :teacher="teacher"
           :position="null"
           narrow
+          @filter-user="(name: string) => ((mobilePane = false), filterUser(name))"
+          @filter-problem="(id: string) => ((mobilePane = false), filterProblem(id))"
           @open-problem="openProblem"
+          @retry="retryFlowchart"
         />
         <SubmissionPane
           v-else
           :row="selectedRow as SubmissionListItem"
-          :teacher="false"
+          :teacher="teacher"
           :contest="inContest"
           :position="null"
           narrow
+          @filter-user="(name: string) => ((mobilePane = false), filterUser(name))"
+          @filter-problem="(id: string) => ((mobilePane = false), filterProblem(id))"
           @open-problem="openProblem"
+          @rejudge="rejudge"
         />
       </div>
       <!-- 手机没有方向键：上一条 / 下一条换成按钮，走的是同一个 move() -->
@@ -932,7 +1023,12 @@ function dayBreak(index: number) {
           <span class="mobile-pos">{{
             position ? `${position.index} / ${position.count}` : ""
           }}</span>
-          <n-button @click="move(1)">下一条</n-button>
+          <n-button
+            :disabled="!position || (position.index >= position.count && query.page >= maxPage)"
+            @click="move(1)"
+          >
+            下一条
+          </n-button>
         </n-flex>
       </template>
     </n-drawer-content>
@@ -1157,6 +1253,11 @@ function dayBreak(index: number) {
   font-size: 14px;
 }
 
+/* 往上翻时选中那一行别被吸顶的日期行挡住 */
+.row {
+  scroll-margin-top: 28px;
+}
+
 .row:hover {
   background: v-bind("theme.hoverColor");
 }
@@ -1271,6 +1372,10 @@ function dayBreak(index: number) {
   justify-content: flex-end;
 }
 
+.lock-hint {
+  display: flex;
+}
+
 .c-lock {
   width: 14px;
   flex: none;
diff --git a/apps/web/src/shared/composables/hiddenStudents.ts b/apps/web/src/shared/composables/hiddenStudents.ts
index 2101180..66dc401 100644
--- a/apps/web/src/shared/composables/hiddenStudents.ts
+++ b/apps/web/src/shared/composables/hiddenStudents.ts
@@ -1,21 +1,19 @@
 import { onMounted, ref } from "vue"
 
 /**
- * 统计面板的「暂时隐藏某个学生」。
+ * 课堂看板的「请假隐藏」：暂时把某个学生从「今天还没交过」里藏起来。
  *
- * 老师是把面板投在屏幕上盯着看的，未完成名单里总有那么几个是请假/转班/学号错了的，
+ * 老师是把看板投在屏幕上盯着看的，没交名单里总有那么几个是请假/转班/学号错了的，
  * 一直挂在上面会盖住真正需要盯的人。隐藏是**带过期时间**的（两小时，够一节课），
  * 不是永久删除 —— 下节课自动回来，免得有人被无声地漏掉。
  *
  * 存在 localStorage 而不是后端：这是「这台电脑上这位老师这节课不想看谁」，
  * 换个人、换台机器都不该继承。
  *
- * 原来这套（loadHidden / saveHidden / hideStudent / showAll / 过期清理）在
- * StatisticsPanel.vue 和 FlowchartStatisticsPanel.vue 里各写了一遍，除了存储键
- * 和一个参数名逐字相同；判断「有没有被隐藏」两边还各自内联了三处。
+ * 原来在提交统计、流程图统计两个弹框里；统计改成回头看的页面之后（2026-09），
+ * 课上盯人的事归看板，这个也挪了过来。
  *
- * @param storageKey localStorage 的键。**两个面板各用各的** —— 提交统计里隐掉的人
- *   不该连带在流程图统计里也消失，那是两件事。
+ * @param storageKey localStorage 的键
  */
 export function useHiddenStudents(storageKey: string) {
   /** 隐藏时长：两小时，一节课的量级 */
@@ -30,7 +28,7 @@ export function useHiddenStudents(storageKey: string) {
   }
 
   const hiddenStudents = ref<Record<string, number>>(load())
-  /** 面板上的「隐藏模式」开关：打开后每行才出现那个隐藏按钮 */
+  /** 「请假隐藏」开关：打开后名字旁边才出现那个 × */
   const hideMode = ref(false)
 
   function save(data: Record<string, number>) {
@@ -45,9 +43,13 @@ export function useHiddenStudents(storageKey: string) {
     save(hiddenStudents.value)
   }
 
-  function showAll() {
-    hiddenStudents.value = {}
-    save({})
+  /** 恢复这几个人。只恢复看板上这个班的，别把别的班藏着的人一起放出来 */
+  function unhide(usernames: string[]) {
+    const drop = new Set(usernames)
+    hiddenStudents.value = Object.fromEntries(
+      Object.entries(hiddenStudents.value).filter(([name]) => !drop.has(name)),
+    )
+    save(hiddenStudents.value)
   }
 
   function isHidden(username: string) {
@@ -55,11 +57,6 @@ export function useHiddenStudents(storageKey: string) {
     return !!expiresAt && expiresAt > Date.now()
   }
 
-  /** 给 filter 用：`list.filter(notHidden)` */
-  function notHidden(item: { username: string }) {
-    return !isHidden(item.username)
-  }
-
   onMounted(() => {
     // 把已经到期的清掉再落一次盘，否则这张表只增不减
     const now = Date.now()
@@ -70,7 +67,7 @@ export function useHiddenStudents(storageKey: string) {
     save(cleaned)
   })
 
-  // 不导出 hiddenStudents 本身：两个面板要的都是「这个人该不该显示」，
-  // 把那张表递出去只会让判断逻辑又散回各自的组件里
-  return { hideMode, hideStudent, showAll, isHidden, notHidden }
+  // 不导出 hiddenStudents 本身：用的地方要的是「这个人该不该显示」，
+  // 把那张表递出去只会让判断逻辑又散回组件里
+  return { hideMode, hideStudent, unhide, isHidden }
 }