fix(手机): 点开提交、班级详情、自学目录这类整屏的东西，按返回直接退出了整页，现在是先关掉它

- 提交列表：手机上点开一条，地址带上 ?id=，返回键就是关详情回到列表；刷新、转发链接
  也还停在这一条；上一条 / 下一条、翻页、滚动位置都在；详情里点「只看他」先关详情再筛选
- 看板讲错误、排名班级详情、自学目录、题目页底部抽屉：手机上按返回只关它（useBackClose）；
  在自学目录里选一课，返回是回到上一课，不多一站
- 分页列表（提交、题目、比赛、后台几个列表）用浏览器后退翻回前一页时会多压一条历史，
  前进的记录被冲掉、返回要多按一次 —— 电脑上也是，一起修了

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/web/src/oj/classroom/board.vue

@@ -615,7 +615,13 @@ function shortTitle(title: string, size: number) {
             </span>
             <span class="muted">没做 {{ problemStats[selectedIndex]!.none }} 人</span>
             <div class="spacer"></div>
-            <n-button quaternary size="small" aria-label="收起" @click="selectedId = null">
+            <n-button
+              quaternary
+              size="small"
+              class="panel-close"
+              aria-label="收起"
+              @click="selectedId = null"
+            >
               <template #icon><Icon icon="ph:x-bold" /></template>
             </n-button>
           </div>
@@ -700,8 +706,10 @@ function shortTitle(title: string, size: number) {
             <template v-for="student in students" :key="student.userId">
               <tr v-if="groupStarts.has(student.userId)" class="group-row">
                 <td :colspan="board.problems.length + 4">
-                  {{ GROUP_LABEL[groupOf(student)] }}
-                  <span class="muted">{{ groupCount[groupOf(student)] }}</span>
+                  <span class="group-label">
+                    {{ GROUP_LABEL[groupOf(student)] }}
+                    <span class="muted">{{ groupCount[groupOf(student)] }}</span>
+                  </span>
                 </td>
               </tr>
               <tr :class="{ 'leave-row': groupOf(student) === 'leave' }">
@@ -1164,6 +1172,14 @@ a.who {
   color: inherit;
 }
 
+/* 题多了表格要横着滑，名字钉在左边，不然滑过去就不知道是谁的格子 */
+.grid .name {
+  position: sticky;
+  left: 0;
+  z-index: 1;
+  background: v-bind("theme.cardColor");
+}
+
 .grid th.col {
   width: 96px;
   cursor: pointer;
@@ -1213,6 +1229,12 @@ a.who {
   background: v-bind("theme.actionColor");
 }
 
+/* 和名字一样钉在左边：横着滑过去也看得见这一组是什么 */
+.group-label {
+  position: sticky;
+  left: 12px;
+}
+
 .group-row .muted {
   margin-left: 4px;
   font-weight: 400;
@@ -1314,4 +1336,57 @@ a.cell {
 .meta {
   font-size: var(--oj-fs-sec);
 }
+
+/* ---------- 手机 ---------- */
+
+@media (max-width: 768px) {
+  /* 题名占一行（收起钉在右边），人数挪到第二行，别把「人」挤到下一行去 */
+  .panel-head {
+    flex-wrap: wrap;
+    gap: 6px 12px;
+  }
+
+  .panel-head > span {
+    order: 2;
+    white-space: nowrap;
+  }
+
+  .panel-title {
+    flex: 1 1 calc(100% - 50px);
+    min-width: 0;
+  }
+
+  .panel-head .spacer {
+    display: none;
+  }
+
+  .panel-close {
+    order: 1;
+  }
+
+  .err-group {
+    min-width: 0;
+    flex: 1 1 100%;
+    box-sizing: border-box;
+  }
+
+  .start-row {
+    flex-wrap: wrap;
+  }
+
+  .start-input {
+    flex-basis: 100%;
+    order: -1;
+  }
+
+  .grid .name {
+    width: auto;
+    padding-left: 4px;
+    padding-right: 8px;
+  }
+
+  .cell {
+    width: 48px;
+  }
+}
 </style>

apps/web/src/oj/classroom/components/ExplainModal.vue

@@ -14,6 +14,8 @@ import { onKeyStroke } from "@vueuse/core"
 import { useThemeVars } from "naive-ui"
 import SubmissionView from "oj/submission/components/SubmissionView.vue"
 import UserName from "shared/components/UserName.vue"
+import { useBackClose } from "shared/composables/backClose"
+import { useBreakpoints } from "shared/composables/breakpoints"
 import type { ClassBoardProblem } from "utils/types"
 import ProblemBrief from "./ProblemBrief.vue"
 
@@ -24,6 +26,9 @@ import ProblemBrief from "./ProblemBrief.vue"
  *
  * 「题目」按钮：演示错误时题目和代码要并排（用户要的），点了左边出题目，再点收起。
  * 平时收着，代码照样占满宽。开没开记在这台电脑上，讲下一个人、下一道题还是那样
+ *
+ * 手机上（老师拿手机看看板）：顶上拆成三行 —— 题目和关闭、一排人（横着滑）、两个按钮；
+ * 没有键盘所以不写「← → 换人」；题目展开时叠在代码上面，不并排
  */
 const props = defineProps<{
   problem: ClassBoardProblem | null
@@ -33,6 +38,9 @@ const show = defineModel<boolean>("show", { required: true })
 const index = defineModel<number>("index", { required: true })
 
 const theme = useThemeVars()
+const { isMobile } = useBreakpoints()
+// 手机上是整屏的：按返回键关掉它回到看板，不是退出看板
+useBackClose(show, isMobile)
 /**
  * 颜色走内联的 CSS 变量，不用 <style> 里的 v-bind()：n-modal 把内容挂到 body 下面，
  * v-bind 的变量挂在组件根上，传不过去（弹层底色整个透明）
@@ -50,6 +58,16 @@ const vars = computed(() => ({
 const current = computed(() => props.people[index.value] ?? null)
 const showProblem = useStorage("oj_explain_show_problem", false)
 
+/** 一排人横着滑的时候，换到的人要滑进来（← → 换人、或者点开的就是排在后面的） */
+const peopleRef = ref<HTMLElement | null>(null)
+watch([index, show], async () => {
+  if (!show.value) return
+  await nextTick()
+  peopleRef.value
+    ?.querySelector<HTMLElement>(".person.on")
+    ?.scrollIntoView({ block: "nearest", inline: "nearest" })
+})
+
 function step(delta: -1 | 1) {
   const next = index.value + delta
   if (next >= 0 && next < props.people.length) index.value = next
@@ -68,6 +86,7 @@ onKeyStroke(["ArrowLeft", "ArrowRight"], (event) => {
     <!-- 无 preset 的 n-modal 直接子节点要是普通元素 -->
     <div
       class="sheet"
+      :class="{ narrow: isMobile }"
       :style="vars"
       role="dialog"
       :aria-label="problem ? `讲 ${problem.problemDisplayId} 的错误` : '讲错误'"
@@ -77,7 +96,7 @@ onKeyStroke(["ArrowLeft", "ArrowRight"], (event) => {
           <b>{{ problem.problemDisplayId }}</b> {{ problem.title }}
           <template v-if="people.length > 1"> · 错着的</template>
         </span>
-        <div class="people">
+        <div ref="peopleRef" class="people">
           <button
             v-for="(person, i) in people"
             :key="person.userId"
@@ -90,25 +109,31 @@ onKeyStroke(["ArrowLeft", "ArrowRight"], (event) => {
             <span class="kind">{{ person.label }}</span>
           </button>
         </div>
-        <span v-if="people.length > 1" class="keys"><kbd>←</kbd><kbd>→</kbd> 换人</span>
+        <span v-if="people.length > 1 && !isMobile" class="keys"
+          ><kbd>←</kbd><kbd>→</kbd> 换人</span
+        >
         <div class="spacer"></div>
-        <n-button
-          v-if="problem"
-          :type="showProblem ? 'primary' : 'default'"
-          :secondary="showProblem"
-          @click="showProblem = !showProblem"
-        >
-          题目
-        </n-button>
-        <n-button
-          v-if="current"
-          tag="a"
-          :href="'/submission/' + current.submissionId"
-          target="_blank"
-        >
-          在新页面打开
-        </n-button>
-        <n-button quaternary aria-label="关闭" @click="show = false">
+        <div class="buttons">
+          <n-button
+            v-if="problem"
+            :size="isMobile ? 'small' : 'medium'"
+            :type="showProblem ? 'primary' : 'default'"
+            :secondary="showProblem"
+            @click="showProblem = !showProblem"
+          >
+            题目
+          </n-button>
+          <n-button
+            v-if="current"
+            :size="isMobile ? 'small' : 'medium'"
+            tag="a"
+            :href="'/submission/' + current.submissionId"
+            target="_blank"
+          >
+            在新页面打开
+          </n-button>
+        </div>
+        <n-button quaternary class="close" aria-label="关闭" @click="show = false">
           <template #icon><Icon icon="ph:x-bold" /></template>
         </n-button>
       </div>
@@ -238,4 +263,70 @@ kbd {
 .main {
   min-width: 0;
 }
+
+.buttons {
+  display: flex;
+  gap: 10px;
+}
+
+/* ---------- 手机 ---------- */
+
+.sheet.narrow {
+  width: calc(100vw - 16px);
+  max-height: calc(100vh - 16px);
+  padding: 12px 14px 16px;
+  gap: 12px;
+}
+
+/* 第一行题目 + 关闭，第二行一排人（横着滑），第三行两个按钮 */
+.narrow .top {
+  display: grid;
+  grid-template-columns: minmax(0, 1fr) auto;
+  gap: 10px;
+}
+
+.narrow .problem {
+  grid-row: 1;
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
+
+.narrow .close {
+  grid-row: 1;
+  grid-column: 2;
+  margin-right: -6px;
+}
+
+.narrow .people {
+  grid-column: 1 / -1;
+  flex-wrap: nowrap;
+  overflow-x: auto;
+  scrollbar-width: none;
+}
+
+.narrow .person {
+  flex-shrink: 0;
+}
+
+.narrow .spacer {
+  display: none;
+}
+
+.narrow .buttons {
+  grid-column: 1 / -1;
+}
+
+/* 题目叠在代码上面，自己滚，别把代码顶出一屏 */
+.narrow .body.split {
+  display: flex;
+  flex-direction: column;
+  gap: 14px;
+}
+
+.narrow .statement {
+  position: static;
+  max-height: 40vh;
+  padding: 0 0 12px;
+  border-bottom: 1px solid var(--divider);
+}
 </style>

apps/web/src/oj/learn/index.vue

@@ -6,6 +6,7 @@ import type { Exercise } from "utils/types"
 import { getExercises, getLearnProgress, getTutorial, getTutorials } from "../api"
 import { parseLesson } from "./composables/useLessonParse"
 import { useLearnTrace } from "./composables/useLearnTrace"
+import { useBackClose } from "shared/composables/backClose"
 import { useBreakpoints } from "shared/composables/breakpoints"
 import { useUserStore } from "shared/store/user"
 import {
@@ -52,6 +53,8 @@ const solvedIds = ref(new Set<number>())
 const loading = ref(true)
 const isEmpty = ref(false)
 const menuOpen = ref(false)
+// 手机上的目录是大半屏的底部抽屉：按返回键收起它，不是退出这一课
+useBackClose(menuOpen, () => !isDesktop.value)
 
 const groups = computed(() => groupByProject(titles.value))
 const parsed = computed(() =>

apps/web/src/oj/problem/components/ProblemDrawer.vue

@@ -2,6 +2,7 @@
 import { useThemeVars } from "naive-ui"
 import { storeToRefs } from "pinia"
 import { useProblemStore } from "oj/store/problem"
+import { useBackClose } from "shared/composables/backClose"
 import { useUserStore } from "shared/store/user"
 import {
   DRAWER_TITLE,
@@ -52,6 +53,8 @@ const show = computed({
     if (!value) open.value = null
   },
 })
+// 手机上是大半屏的底部抽屉（没有 to）：按返回键收起它，不是退出题目
+useBackClose(show, () => !props.to)
 
 // 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

apps/web/src/oj/rank/components/ClassDetailDrawer.vue

@@ -6,6 +6,7 @@ import { getClassDetail } from "oj/api"
 import { classLabel } from "oj/submission/utils"
 import UserName from "shared/components/UserName.vue"
 import { useAIStream } from "shared/composables/aiStream"
+import { useBackClose } from "shared/composables/backClose"
 import { useBreakpoints } from "shared/composables/breakpoints"
 import { parseTime } from "utils/functions"
 import { useRankPalette } from "../palette"
@@ -24,6 +25,8 @@ const message = useMessage()
 const theme = useThemeVars()
 const palette = useRankPalette()
 const { isDesktop } = useBreakpoints()
+// 手机上占满一屏：按返回键关掉它回到排名
+useBackClose(show, () => !isDesktop.value)
 
 const detail = ref<ClassDetail | null>(null)
 const loading = ref(false)

apps/web/src/oj/submission/list.vue

@@ -14,6 +14,7 @@ import {
 import { DEFAULT_PERIOD } from "oj/statistics/period"
 import { useContestStore } from "oj/store/contest"
 import Pagination from "shared/components/Pagination.vue"
+import { useBackClose } from "shared/composables/backClose"
 import { useBreakpoints } from "shared/composables/breakpoints"
 import { usePagination } from "shared/composables/pagination"
 import { useConfigStore } from "shared/store/config"
@@ -71,6 +72,17 @@ const tone = useTone()
 const { isMobile, isDesktop } = useBreakpoints()
 
 const inContest = computed(() => route.name === "contest submissions")
+
+/**
+ * 手机上点开的那一条，记在地址的 `?id=` 上：详情是从右边滑出的整屏，学生下意识按返回 ——
+ * 返回键归路由管，退一步就是关掉详情、回到列表；刷新、转发链接也还停在这一条。
+ * 列表在底下不卸载，滚到哪、上一条 / 下一条都还在
+ */
+const paneId = computed(() =>
+  isMobile.value && typeof route.query.id === "string" ? route.query.id : "",
+)
+/** 从详情里点了「只看他」这类筛选：这一下要连 ?id= 一起换掉，见 leavePane() */
+let leavingPane = false
 const teacher = computed(() => userStore.isTeacherOrAbove)
 
 // 一节课一个班要交一百来条，每页 10 条得翻十几页；30 条配上右栏的方向键正好
@@ -85,7 +97,13 @@ const { query, clearQuery } = usePagination<SubmissionQuery>(
     // 原来写死成 "0"，从别处带着 today=1 进来也不认
     today: useRouteQuery("today", "0").value,
   },
-  { defaultLimit: 30 },
+  {
+    defaultLimit: 30,
+    // 手机上开着详情：翻页、换条件时地址里的 ?id= 带着走，也不多压历史（返回键是关详情）
+    extraQuery: (): Record<string, string> =>
+      paneId.value && !leavingPane ? { id: paneId.value } : {},
+    replace: () => !!paneId.value && !leavingPane,
+  },
 )
 
 const flowMode = computed(() => !inContest.value && query.language === "Flowchart")
@@ -294,6 +312,14 @@ function settleSelection() {
     }
     message.info("这一页没有可以查看的代码")
   }
+  // 地址里带着 ?id= 的（手机上开着详情时刷新、别人发来的链接）就停在那一条
+  const wanted = typeof route.query.id === "string" ? route.query.id : ""
+  if (wanted && rows.value.some((row) => row.id === wanted)) {
+    selectedId.value = wanted
+    return
+  }
+  // 这一页上没有那一条：详情开不出来，把 ?id= 摘掉
+  if (paneId.value) router.replace({ query: queryWithoutId() })
   if (rows.value.some((row) => row.id === selectedId.value)) return
   // 手机上没有右栏，不用预先选一条
   if (isMobile.value) {
@@ -334,6 +360,7 @@ function move(step: 1 | -1) {
 }
 
 const [todayPanel, toggleTodayPanel] = useToggle(false)
+useBackClose(todayPanel, isMobile)
 const statsPanel = ref(false)
 
 // 只用 ↑ ↓（用户定的，← → 不要）
@@ -360,13 +387,63 @@ onKeyStroke(["ArrowUp", "ArrowDown"], (e: KeyboardEvent) => {
   move(e.key === "ArrowUp" ? -1 : 1)
 })
 
-// 手机上没有右栏：点一行从右边滑出整屏的详情
-const mobilePane = ref(false)
+// 手机上没有右栏：点一行从右边滑出整屏的详情，地址带上 ?id=（见 paneId）
+const mobilePane = computed({
+  get: () => !!paneId.value,
+  set: (open) => {
+    if (!open) closePane()
+  },
+})
+
+function queryWithoutId() {
+  const { id: _, ...rest } = route.query
+  return rest
+}
+
 function rowClicked(row: Row) {
   select(row.id)
-  if (isMobile.value) mobilePane.value = true
+  if (isMobile.value) router.push({ query: { ...route.query, id: row.id } })
 }
 
+/**
+ * 点 × 关：从列表点开的就退一步（和按返回键一样，不留一条多余的历史）；
+ * 直接带着 ?id= 进来的（刷新过、别人发的链接）后面没有列表可退，把地址换掉
+ */
+function closePane() {
+  const back = history.state?.back
+  if (typeof back === "string" && router.resolve(back).name === route.name) router.back()
+  else router.replace({ query: queryWithoutId() })
+}
+
+/**
+ * 详情里点「只看他」「只看这道题」：先关详情（退回列表那一条），再改筛选。
+ * 反过来的话筛选压的那条历史在详情后面，按返回又回到详情。
+ * 等路由落地、再等分页把地址同步回 query 之后才改，不然改的值会被同步盖掉
+ */
+function leavePane(next: () => void) {
+  if (!paneId.value) return next()
+  leavingPane = true
+  const off = router.afterEach(() => {
+    off()
+    nextTick(() => {
+      leavingPane = false
+      next()
+    })
+  })
+  closePane()
+}
+
+// 上一条 / 下一条换了人：地址里的 ?id= 跟着换（replace，返回键照样是关详情）
+watch(selectedId, (id) => {
+  if (paneId.value && id && id !== paneId.value) {
+    router.replace({ query: { ...route.query, id } })
+  }
+})
+// 前进后退到另一条（或者刷新后列表回来之前地址就有了）：选中跟着地址走
+watch(paneId, (id) => {
+  if (id && rows.value.some((row) => row.id === id)) selectedId.value = id
+})
+
 // ==================== 实时更新 ====================
 
 /**
@@ -1167,8 +1244,8 @@ function dayBreak(index: number) {
           :teacher="teacher"
           :position="null"
           narrow
-          @filter-user="(name: string) => ((mobilePane = false), filterUser(name))"
-          @filter-problem="(id: string) => ((mobilePane = false), filterProblem(id))"
+          @filter-user="(name: string) => leavePane(() => filterUser(name))"
+          @filter-problem="(id: string) => leavePane(() => filterProblem(id))"
           @open-problem="openProblem"
           @retry="retryFlowchart"
         />
@@ -1180,10 +1257,10 @@ function dayBreak(index: number) {
           :contest="inContest"
           :position="null"
           narrow
-          @filter-user="(name: string) => ((mobilePane = false), filterUser(name))"
-          @filter-class="(name: string) => ((mobilePane = false), filterClass(name))"
-          @clear-class="() => ((mobilePane = false), (query.className = ''))"
-          @filter-problem="(id: string) => ((mobilePane = false), filterProblem(id))"
+          @filter-user="(name: string) => leavePane(() => filterUser(name))"
+          @filter-class="(name: string) => leavePane(() => filterClass(name))"
+          @clear-class="() => leavePane(() => (query.className = ''))"
+          @filter-problem="(id: string) => leavePane(() => filterProblem(id))"
           @open-problem="openProblem"
           @rejudge="rejudge"
         />

apps/web/src/shared/composables/backClose.ts

@@ -0,0 +1,65 @@
+import type { MaybeRefOrGetter, Ref } from "vue"
+
+/**
+ * 手机上整屏（或大半屏）的弹框、抽屉：按返回键先关它，而不是退出整页。
+ *
+ * 学生在手机上看到一整屏的东西，下意识就按返回 —— 原来这一下直接退到了前一页（提交列表点开
+ * 一条、再按返回，回到的是首页）。所以打开时往历史里压一条同地址的记录：
+ * - 按返回：浏览器弹掉这一条，这里收到 popstate，把弹框关掉，页面原地不动；
+ * - 点 × / 点遮罩关掉：自己 history.back() 把那条弹掉，不然要多按一次返回才退得出去。
+ *
+ * 压的是 history.state 的原样拷贝（vue-router 要的 position 等字段都在）。弹掉它时
+ * **不能让 vue-router 看见**：它会当成一次同地址的跳转，route 对象换新，页面上盯着
+ * route.query 的同步逻辑（usePagination）跟着跑一遍，又压一条历史，返回键就要多按一次。
+ * 抢在它前面拦不住 —— window 上的 popstate 按注册顺序派发（捕获监听也不优先，实测过），
+ * 路由的监听最早注册。所以记录压着的这段时间把 router.listening 整个关掉，弹掉以后再开：
+ * 关着的只是「响应浏览器前进后退」这一项，弹框里点链接 router.push 照常走。
+ *
+ * 弹框开着时点了站内链接，路由守卫先把它拦下，等那条记录弹完再跳（back() 是异步的，
+ * 先跳的话会把刚跳过去的那一条弹掉）。
+ */
+export function useBackClose(show: Ref<boolean>, enabled: MaybeRefOrGetter<boolean> = true) {
+  const router = useRouter()
+  /** 压了记录、还没弹掉（这段时间路由不听前进后退） */
+  let pushed = false
+  let afterPop: (() => void) | null = null
+
+  watch(show, (open) => {
+    if (open && !pushed && toValue(enabled)) {
+      history.pushState(history.state, "")
+      pushed = true
+      router.listening = false
+    } else if (!open && pushed) {
+      // 点 × 关的：自己弹掉那条，路由照旧关着，等下面收到 popstate 再开
+      history.back()
+    }
+  })
+
+  useEventListener(window, "popstate", () => {
+    if (!pushed) return
+    pushed = false
+    // 按了返回键的：只管关（watch 里看到 pushed 已经是 false，不会再 back）
+    show.value = false
+    router.listening = true
+    const next = afterPop
+    afterPop = null
+    next?.()
+  })
+
+  // 弹框里点了链接要跳走（自学目录里选一课）：先关弹框、把压的那条退掉，再跳。
+  // 直接跳的话新页面压在那条后面，回来时要多按一次返回，而且那一下路由不听（见上）
+  const removeGuard = router.beforeEach((to) => {
+    if (!pushed) return
+    afterPop = () => void router.push(to.fullPath)
+    show.value = false
+    return false
+  })
+
+  // 弹框开着组件就没了：路由一定要开回来，不然整站的返回键都失灵
+  onBeforeUnmount(() => {
+    removeGuard()
+    if (!pushed) return
+    pushed = false
+    router.listening = true
+  })
+}

apps/web/src/shared/composables/pagination.ts

@@ -1,4 +1,4 @@
-import { reactive, watch } from "vue"
+import { nextTick, reactive, watch } from "vue"
 import { useRoute, useRouter } from "vue-router"
 import { filterEmptyValue } from "utils/functions"
 
@@ -15,6 +15,13 @@ export interface UsePaginationOptions {
   defaultPage?: number
   /** 当其他查询条件变化时是否重置页码 */
   resetPageOnChange?: boolean
+  /**
+   * 不归分页管、但同步地址时要带上的键。不给的话地址整个按 query 重写，别的键会被丢掉
+   * （提交列表手机上点开一条是 `?id=`，翻一页详情就关了）
+   */
+  extraQuery?: () => Record<string, string>
+  /** 返回 true 时同步地址一律 replace，不压历史（提交列表手机上开着详情时翻页） */
+  replace?: () => boolean
 }
 
 /**
@@ -27,7 +34,13 @@ export function usePagination<T extends Record<string, any>>(
   initialQuery: Omit<T, "page" | "limit"> = {} as Omit<T, "page" | "limit">,
   options: UsePaginationOptions = {},
 ) {
-  const { defaultLimit = 10, defaultPage = 1, resetPageOnChange = true } = options
+  const {
+    defaultLimit = 10,
+    defaultPage = 1,
+    resetPageOnChange = true,
+    extraQuery,
+    replace,
+  } = options
 
   const route = useRoute()
   const router = useRouter()
@@ -41,8 +54,18 @@ export function usePagination<T extends Record<string, any>>(
   // 键是运行时按 initialQuery 枚举出来的，静态类型写不出来；写入统一走这一个口子
   const writable = query as Record<string, unknown>
 
+  /**
+   * 正在从地址同步回来：这一拍里 query 的变化本来就是地址带来的，别再写回地址。
+   * 写回去的话（浏览器后退到第 1 页，地址没写默认的 today=0，比一下「不一样」）会压一条
+   * 新历史，把前进的那几条冲掉，返回键还得多按一次。
+   * 页面自己盯着 route.query 补默认值的（提交列表）也在同一拍里，一起算
+   */
+  let syncing = false
+
   // 同步 URL 查询参数到本地状态
   function syncFromRoute() {
+    syncing = true
+    nextTick(() => (syncing = false))
     writable.page = parseInt(<string>route.query.page) || defaultPage
     writable.limit = parseInt(<string>route.query.limit) || defaultLimit
 
@@ -71,7 +94,7 @@ export function usePagination<T extends Record<string, any>>(
 
   // 更新 URL
   function updateRoute() {
-    const newQuery = filterEmptyValue(query)
+    const newQuery = { ...filterEmptyValue(query), ...extraQuery?.() }
     // 和当前地址只差默认的 page / limit（后退到 /problem，同步完又补上 ?page=1&limit=30）：
     // 是同一个页面，用 replace，别多压一条历史、让人得多按一次后退
     const normalized = (q: Record<string, unknown>) =>
@@ -85,7 +108,8 @@ export function usePagination<T extends Record<string, any>>(
           .map(([key, value]) => [key, String(value)])
           .sort(),
       )
-    const navigate = normalized(route.query) === normalized(newQuery) ? router.replace : router.push
+    const navigate =
+      replace?.() || normalized(route.query) === normalized(newQuery) ? router.replace : router.push
     navigate({
       path: route.path,
       query: newQuery,
@@ -115,12 +139,18 @@ export function usePagination<T extends Record<string, any>>(
   }
 
   // 监听页码变化，同步到 URL
-  watch(() => query.page, updateRoute)
+  watch(
+    () => query.page,
+    () => {
+      if (!syncing) updateRoute()
+    },
+  )
 
   // 监听每页条数变化，重置页码并同步到 URL
   watch(
     () => query.limit,
     () => {
+      if (syncing) return
       if (resetPageOnChange) {
         resetPage()
       }
@@ -134,6 +164,7 @@ export function usePagination<T extends Record<string, any>>(
     watch(
       () => otherQueryKeys.map((key) => query[key]),
       () => {
+        if (syncing) return
         resetPage()
         updateRoute()
       },