diff --git a/backend/internal/modules/chat/dto.go b/backend/internal/modules/chat/dto.go
index fb2fc8f..2c5e161 100644
--- a/backend/internal/modules/chat/dto.go
+++ b/backend/internal/modules/chat/dto.go
@@ -51,6 +51,10 @@ type MessageDTO struct {
 	CreatedAt      time.Time `json:"created_at"`
 }
 
+type UnreadCountDTO struct {
+	UnreadCount int64 `json:"unread_count"`
+}
+
 type SendMessageRequest struct {
 	Content        string   `json:"content"`
 	AttachmentURLS []string `json:"attachment_urls"`
diff --git a/backend/internal/modules/chat/handler_user.go b/backend/internal/modules/chat/handler_user.go
index 39dc2f8..cb2d0bd 100644
--- a/backend/internal/modules/chat/handler_user.go
+++ b/backend/internal/modules/chat/handler_user.go
@@ -15,6 +15,20 @@ func (h *Handler) List(c *gin.Context) {
 	h.list(c, Principal{Type: "user", ID: userID})
 }
 
+func (h *Handler) UnreadCount(c *gin.Context) {
+	userID, ok := currentUserID(c)
+	if !ok {
+		response.Unauthorized(c, "缺少用户上下文")
+		return
+	}
+	result, err := h.service.CountUnreadMessages(c.Request.Context(), Principal{Type: "user", ID: userID})
+	if err != nil {
+		writeChatError(c, err)
+		return
+	}
+	response.OK(c, result)
+}
+
 func (h *Handler) Detail(c *gin.Context) {
 	userID, ok := currentUserID(c)
 	if !ok {
diff --git a/backend/internal/modules/chat/participant.go b/backend/internal/modules/chat/participant.go
index b3b166a..b8e640e 100644
--- a/backend/internal/modules/chat/participant.go
+++ b/backend/internal/modules/chat/participant.go
@@ -40,6 +40,18 @@ func (r *Repository) conversationQuery(ctx context.Context, principal Principal)
 		Joins("JOIN chat_participants AS cp ON cp.conversation_id = c.id").
 		Where("cp.participant_type = ? AND cp.participant_id = ?", principal.Type, principal.ID)
 }
+
+func (r *Repository) CountUnreadMessages(ctx context.Context, principal Principal) (int64, error) {
+	var total int64
+	err := r.db.WithContext(ctx).Table("chat_messages AS cm").
+		Joins("JOIN chat_participants AS cp ON cp.conversation_id = cm.conversation_id").
+		Where("cp.participant_type = ? AND cp.participant_id = ?", principal.Type, principal.ID).
+		Where("NOT (cm.sender_type = ? AND cm.sender_id = ?)", principal.Type, principal.ID).
+		Where("(cp.last_read_at IS NULL OR cm.created_at > cp.last_read_at)").
+		Count(&total).Error
+	return total, err
+}
+
 func (r *Repository) findParticipant(tx *gorm.DB, principal Principal, conversationID uint64, lock bool) (*model.ChatParticipant, error) {
 	var participant model.ChatParticipant
 	db := tx
diff --git a/backend/internal/modules/chat/service.go b/backend/internal/modules/chat/service.go
index 409aa98..37c7ce7 100644
--- a/backend/internal/modules/chat/service.go
+++ b/backend/internal/modules/chat/service.go
@@ -29,6 +29,17 @@ func (s *Service) ListConversations(ctx context.Context, principal Principal, pa
 	return s.repo.ListConversations(ctx, principal, page, pageSize)
 }
 
+func (s *Service) CountUnreadMessages(ctx context.Context, principal Principal) (*UnreadCountDTO, error) {
+	if s.repo == nil {
+		return nil, ErrDependencyUnavailable
+	}
+	total, err := s.repo.CountUnreadMessages(ctx, principal)
+	if err != nil {
+		return nil, err
+	}
+	return &UnreadCountDTO{UnreadCount: total}, nil
+}
+
 func (s *Service) FindConversation(ctx context.Context, principal Principal, id uint64) (*ConversationDTO, error) {
 	if s.repo == nil {
 		return nil, ErrDependencyUnavailable
diff --git a/backend/internal/router/router.go b/backend/internal/router/router.go
index a6786a1..24287d7 100644
--- a/backend/internal/router/router.go
+++ b/backend/internal/router/router.go
@@ -403,6 +403,7 @@ func New(cfg config.Config, deps Dependencies, logger *zap.Logger) *gin.Engine {
 				chatRoutes.GET("/events", chatHubHandler.UserEvents)
 			}
 			chatRoutes.POST("/support", chatHandler.EnsureSupportConversation)
+			chatRoutes.GET("/unread-count", chatHandler.UnreadCount)
 			chatRoutes.GET("", chatHandler.List)
 			chatRoutes.GET("/:id", chatHandler.Detail)
 			chatRoutes.GET("/:id/messages", chatHandler.Messages)
diff --git a/frontend/src/components/MobileBottomNav.vue b/frontend/src/components/MobileBottomNav.vue
index 903221a..cadc0e6 100644
--- a/frontend/src/components/MobileBottomNav.vue
+++ b/frontend/src/components/MobileBottomNav.vue
@@ -1,7 +1,9 @@
 <script setup lang="ts">
 import { useRoute, RouterLink } from 'vue-router'
+import { useChatUnreadCount } from '@/features/chats/composables/useChatUnreadCount'
 
 const route = useRoute()
+const { unreadCount, unreadLabel } = useChatUnreadCount(route)
 
 function isNavActive(path: string) {
   if (path === '/m') return route.path === '/m'
@@ -16,7 +18,10 @@ function isNavActive(path: string) {
       <span>首页</span>
     </RouterLink>
     <RouterLink to="/m/messages" class="nav-item" :class="{ active: isNavActive('/m/messages') }">
-      <van-icon name="chat-o" :size="22" />
+      <span class="nav-icon-wrap">
+        <van-icon name="chat-o" :size="22" />
+        <em v-if="unreadCount > 0" class="nav-badge">{{ unreadLabel }}</em>
+      </span>
       <span>消息</span>
     </RouterLink>
     <RouterLink to="/m/seller/listings/create" class="nav-item nav-publish">
@@ -39,16 +44,26 @@ function isNavActive(path: string) {
   position: fixed;
   left: 0;
   right: 0;
-  bottom: 0;
+  bottom: -1px;
   z-index: 100;
   display: flex;
   background: #fff;
   border-top: 1px solid #eee;
   padding-bottom: env(safe-area-inset-bottom);
-  height: calc(50px + env(safe-area-inset-bottom));
+  height: calc(52px + env(safe-area-inset-bottom));
   box-sizing: border-box;
 }
 
+.bottom-nav::after {
+  position: absolute;
+  right: 0;
+  bottom: -18px;
+  left: 0;
+  height: 18px;
+  background: #fff;
+  content: '';
+}
+
 .nav-item {
   flex: 1;
   display: flex;
@@ -69,6 +84,33 @@ function isNavActive(path: string) {
   font-weight: 600;
 }
 
+.nav-icon-wrap {
+  position: relative;
+  display: grid;
+  width: 24px;
+  height: 24px;
+  place-items: center;
+}
+
+.nav-badge {
+  position: absolute;
+  top: -5px;
+  right: -10px;
+  min-width: 16px;
+  height: 16px;
+  padding: 0 4px;
+  box-sizing: border-box;
+  border: 2px solid #fff;
+  border-radius: 999px;
+  background: #ef4444;
+  color: #fff;
+  font-size: 10px;
+  font-style: normal;
+  font-weight: 800;
+  line-height: 12px;
+  text-align: center;
+}
+
 .publish-pill {
   width: 36px;
   height: 26px;
diff --git a/frontend/src/features/chats/api/chats.ts b/frontend/src/features/chats/api/chats.ts
index 594b5cb..a90afb6 100644
--- a/frontend/src/features/chats/api/chats.ts
+++ b/frontend/src/features/chats/api/chats.ts
@@ -52,6 +52,16 @@ export async function fetchChats(page = 1, pageSize = 20) {
   return data.data
 }
 
+export async function fetchUnreadChatCount() {
+  const { data } = await apiClient.get<ApiResponse<{ unread_count: number }>>(
+    '/chats/unread-count',
+    {
+      silent: true,
+    }
+  )
+  return data.data.unread_count
+}
+
 export async function fetchChat(id: number) {
   const { data } = await apiClient.get<ApiResponse<ChatConversation>>(`/chats/${id}`)
   return data.data
diff --git a/frontend/src/features/chats/composables/useChatUnreadCount.ts b/frontend/src/features/chats/composables/useChatUnreadCount.ts
new file mode 100644
index 0000000..fb5fa11
--- /dev/null
+++ b/frontend/src/features/chats/composables/useChatUnreadCount.ts
@@ -0,0 +1,77 @@
+import { computed, onBeforeUnmount, onMounted, ref, watch } from 'vue'
+import type { RouteLocationNormalizedLoaded } from 'vue-router'
+
+import { fetchUnreadChatCount } from '@/features/chats/api/chats'
+import { useSessionStore } from '@/stores/session'
+
+export function useChatUnreadCount(route: RouteLocationNormalizedLoaded) {
+  const session = useSessionStore()
+  const unreadCount = ref(0)
+  let timer: number | null = null
+  let requestID = 0
+
+  const unreadLabel = computed(() => (unreadCount.value > 99 ? '99+' : String(unreadCount.value)))
+
+  function stopPolling() {
+    if (timer) {
+      window.clearInterval(timer)
+      timer = null
+    }
+  }
+
+  async function loadUnreadCount() {
+    if (!session.isLoggedIn) {
+      unreadCount.value = 0
+      return
+    }
+
+    const currentID = ++requestID
+    try {
+      const count = await fetchUnreadChatCount()
+      if (currentID === requestID) {
+        unreadCount.value = count
+      }
+    } catch {
+      // 底部导航不弹错误提示，保持上一次未读数即可。
+    }
+  }
+
+  function startPolling() {
+    stopPolling()
+    void loadUnreadCount()
+    timer = window.setInterval(loadUnreadCount, 30_000)
+  }
+
+  onMounted(() => {
+    if (session.isLoggedIn) {
+      startPolling()
+    }
+  })
+
+  onBeforeUnmount(stopPolling)
+
+  watch(
+    () => session.isLoggedIn,
+    loggedIn => {
+      if (loggedIn) {
+        startPolling()
+        return
+      }
+      stopPolling()
+      unreadCount.value = 0
+    }
+  )
+
+  watch(
+    () => route.fullPath,
+    () => {
+      void loadUnreadCount()
+    }
+  )
+
+  return {
+    unreadCount,
+    unreadLabel,
+    refreshUnreadCount: loadUnreadCount,
+  }
+}
diff --git a/frontend/src/features/listings/views/MobileHomeFilterSheet.vue b/frontend/src/features/listings/views/MobileHomeFilterSheet.vue
index ec2f8e2..aacb4c0 100644
--- a/frontend/src/features/listings/views/MobileHomeFilterSheet.vue
+++ b/frontend/src/features/listings/views/MobileHomeFilterSheet.vue
@@ -33,6 +33,7 @@ const emit = defineEmits<{
   'update:show': [value: boolean]
   'update:selectedFilters': [value: SelectedFilters]
   'update:rangeFilters': [value: RangeFilters]
+  reset: []
 }>()
 
 const activeCount = computed(() => {
@@ -105,8 +106,7 @@ function isRangePresetActive(sectionKey: string, min: string, max: string) {
 }
 
 function resetFilters() {
-  emit('update:selectedFilters', {})
-  emit('update:rangeFilters', {})
+  emit('reset')
 }
 
 function scrollToSection(sectionKey: string) {
diff --git a/frontend/src/features/listings/views/MobileHomeView.css b/frontend/src/features/listings/views/MobileHomeView.css
index 04ccb98..ddd5bda 100644
--- a/frontend/src/features/listings/views/MobileHomeView.css
+++ b/frontend/src/features/listings/views/MobileHomeView.css
@@ -3,15 +3,12 @@
   max-width: 430px;
   min-height: 100vh;
   margin: 0 auto;
-  padding-bottom: 68px;
+  padding-bottom: calc(72px + env(safe-area-inset-bottom));
   background: #f6f8fb;
   color: #17233d;
 }
 
 .mobile-hero {
-  position: sticky;
-  top: 0;
-  z-index: 20;
   padding: 12px 12px 10px;
   background: #fff;
   box-shadow: 0 1px 0 rgba(15, 23, 42, 0.06);
diff --git a/frontend/src/features/listings/views/MobileHomeView.vue b/frontend/src/features/listings/views/MobileHomeView.vue
index 97a83c3..2805898 100644
--- a/frontend/src/features/listings/views/MobileHomeView.vue
+++ b/frontend/src/features/listings/views/MobileHomeView.vue
@@ -825,6 +825,7 @@ syncMobileHomeQuery()
       v-model:range-filters="rangeFilters"
       :sections="filterSections"
       :range-presets="rangePresets"
+      @reset="clearFilters"
     />
 
     <button
diff --git a/frontend/src/shared/components/layout/MobileBottomNav.vue b/frontend/src/shared/components/layout/MobileBottomNav.vue
index e4cf7b8..15a9225 100644
--- a/frontend/src/shared/components/layout/MobileBottomNav.vue
+++ b/frontend/src/shared/components/layout/MobileBottomNav.vue
@@ -1,7 +1,9 @@
 <script setup lang="ts">
 import { useRoute, RouterLink } from 'vue-router'
+import { useChatUnreadCount } from '@/features/chats/composables/useChatUnreadCount'
 
 const route = useRoute()
+const { unreadCount, unreadLabel } = useChatUnreadCount(route)
 
 function isNavActive(path: string) {
   if (path === '/m') return route.path === '/m'
@@ -16,7 +18,10 @@ function isNavActive(path: string) {
       <span>首页</span>
     </RouterLink>
     <RouterLink to="/m/messages" class="nav-item" :class="{ active: isNavActive('/m/messages') }">
-      <van-icon name="chat-o" :size="22" />
+      <span class="nav-icon-wrap">
+        <van-icon name="chat-o" :size="22" />
+        <em v-if="unreadCount > 0" class="nav-badge">{{ unreadLabel }}</em>
+      </span>
       <span>消息</span>
     </RouterLink>
     <RouterLink to="/m/seller/listings/create" class="nav-item nav-publish">
@@ -39,16 +44,26 @@ function isNavActive(path: string) {
   position: fixed;
   left: 0;
   right: 0;
-  bottom: 0;
+  bottom: -1px;
   z-index: 100;
   display: flex;
   background: #fff;
   border-top: 1px solid #eee;
   padding-bottom: env(safe-area-inset-bottom);
-  height: calc(50px + env(safe-area-inset-bottom));
+  height: calc(52px + env(safe-area-inset-bottom));
   box-sizing: border-box;
 }
 
+.bottom-nav::after {
+  position: absolute;
+  right: 0;
+  bottom: -18px;
+  left: 0;
+  height: 18px;
+  background: #fff;
+  content: '';
+}
+
 .nav-item {
   flex: 1;
   display: flex;
@@ -69,6 +84,33 @@ function isNavActive(path: string) {
   font-weight: 600;
 }
 
+.nav-icon-wrap {
+  position: relative;
+  display: grid;
+  width: 24px;
+  height: 24px;
+  place-items: center;
+}
+
+.nav-badge {
+  position: absolute;
+  top: -5px;
+  right: -10px;
+  min-width: 16px;
+  height: 16px;
+  padding: 0 4px;
+  box-sizing: border-box;
+  border: 2px solid #fff;
+  border-radius: 999px;
+  background: #ef4444;
+  color: #fff;
+  font-size: 10px;
+  font-style: normal;
+  font-weight: 800;
+  line-height: 12px;
+  text-align: center;
+}
+
 .publish-pill {
   width: 36px;
   height: 26px;