diff --git a/frontend/pages/chat/[[username]].vue b/frontend/pages/chat/[[username]].vue
index d740d74..56cee92 100644
--- a/frontend/pages/chat/[[username]].vue
+++ b/frontend/pages/chat/[[username]].vue
@@ -589,17 +589,16 @@
                         :class="message.isSent ? 'bg-[#95EC69] text-black bubble-tail-r' : 'bg-white text-gray-800 bubble-tail-l'">
                         {{ message.content }}
                       </div>
-                      <a
+                      <button
                         v-if="message.videoThumbUrl && message.videoUrl"
-                        :href="message.videoUrl"
-                        target="_blank"
-                        rel="noreferrer"
+                        type="button"
                         class="absolute inset-0 flex items-center justify-center"
+                        @click.stop="openVideoPreview(message.videoUrl, message.videoThumbUrl)"
                       >
                         <div class="w-12 h-12 rounded-full bg-black/45 flex items-center justify-center">
                           <svg class="w-6 h-6 text-white" fill="currentColor" viewBox="0 0 24 24"><path d="M8 5v14l11-7z"/></svg>
                         </div>
-                      </a>
+                      </button>
                       <div class="absolute inset-0 flex items-center justify-center" v-else-if="message.videoThumbUrl">
                         <div class="w-12 h-12 rounded-full bg-black/45 flex items-center justify-center">
                           <svg class="w-6 h-6 text-white" fill="currentColor" viewBox="0 0 24 24"><path d="M8 5v14l11-7z"/></svg>
@@ -1388,6 +1387,40 @@
       </button>
     </div>
 
+    <!-- 视频预览弹窗 (全局固定定位) -->
+    <div
+      v-if="previewVideoUrl"
+      class="fixed inset-0 z-[13000] bg-black/90 flex items-center justify-center"
+      @click="closeVideoPreview"
+    >
+      <div class="relative max-w-[92vw] max-h-[92vh] flex flex-col items-center" @click.stop>
+        <video
+          :key="previewVideoUrl"
+          :src="previewVideoUrl"
+          :poster="previewVideoPosterUrl"
+          class="max-w-[90vw] max-h-[90vh] object-contain"
+          controls
+          autoplay
+          playsinline
+          @error="onPreviewVideoError"
+        ></video>
+        <div
+          v-if="previewVideoError"
+          class="mt-3 text-xs text-red-200 whitespace-pre-wrap text-center max-w-[90vw]"
+        >
+          {{ previewVideoError }}
+        </div>
+      </div>
+      <button
+        class="absolute top-4 right-4 text-white/80 hover:text-white p-2 rounded-full bg-black/30 hover:bg-black/50 transition-colors"
+        @click.stop="closeVideoPreview"
+      >
+        <svg class="w-6 h-6" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+          <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M6 18L18 6M6 6l12 12"/>
+        </svg>
+      </button>
+    </div>
+
     <!-- 浮动窗口（可拖动）：合并消息 / 链接卡片 -->
     <div
       v-for="win in floatingWindows"
@@ -1561,17 +1594,16 @@
                         @error="onChatHistoryVideoThumbError(rec)"
                       />
                       <div v-else class="px-3 py-2 text-sm text-gray-700">{{ rec.content || '[视频]' }}</div>
-                      <a
+                      <button
                         v-if="rec.videoUrl"
-                        :href="rec.videoUrl"
-                        target="_blank"
-                        rel="noreferrer"
+                        type="button"
                         class="absolute inset-0 flex items-center justify-center"
+                        @click.stop="openVideoPreview(rec.videoUrl, rec.videoThumbUrl)"
                       >
                         <div class="w-12 h-12 rounded-full bg-black/45 flex items-center justify-center">
                           <svg class="w-6 h-6 text-white" fill="currentColor" viewBox="0 0 24 24"><path d="M8 5v14l11-7z"/></svg>
                         </div>
-                      </a>
+                      </button>
                       <div
                         v-if="rec.videoDuration"
                         class="absolute bottom-2 right-2 text-xs text-white bg-black/55 px-1.5 py-0.5 rounded"
@@ -1814,17 +1846,16 @@
                     />
                     <div v-else class="px-3 py-2 text-sm text-gray-700">{{ rec.content || '[视频]' }}</div>
 
-                    <a
+                    <button
                       v-if="rec.videoThumbUrl && rec.videoUrl"
-                      :href="rec.videoUrl"
-                      target="_blank"
-                      rel="noreferrer"
+                      type="button"
                       class="absolute inset-0 flex items-center justify-center"
+                      @click.stop="openVideoPreview(rec.videoUrl, rec.videoThumbUrl)"
                     >
                       <div class="w-12 h-12 rounded-full bg-black/45 flex items-center justify-center">
                         <svg class="w-6 h-6 text-white" fill="currentColor" viewBox="0 0 24 24"><path d="M8 5v14l11-7z"/></svg>
                       </div>
-                    </a>
+                    </button>
                     <div class="absolute inset-0 flex items-center justify-center" v-else-if="rec.videoThumbUrl">
                       <div class="w-12 h-12 rounded-full bg-black/45 flex items-center justify-center">
                         <svg class="w-6 h-6 text-white" fill="currentColor" viewBox="0 0 24 24"><path d="M8 5v14l11-7z"/></svg>
@@ -4070,15 +4101,42 @@ const scrollToMessageId = async (id) => {
 
 // 图片预览状态
 const previewImageUrl = ref(null)
+const previewVideoUrl = ref(null)
+const previewVideoPosterUrl = ref('')
+const previewVideoError = ref('')
 
 const openImagePreview = (url) => {
+  if (!process.client) return
   previewImageUrl.value = url
   document.body.style.overflow = 'hidden'
 }
 
 const closeImagePreview = () => {
+  if (!process.client) return
   previewImageUrl.value = null
-  document.body.style.overflow = ''
+  if (!previewVideoUrl.value) document.body.style.overflow = ''
+}
+
+const openVideoPreview = (url, poster) => {
+  if (!process.client) return
+  const u = String(url || '').trim()
+  if (!u) return
+  previewVideoError.value = ''
+  previewVideoPosterUrl.value = String(poster || '').trim()
+  previewVideoUrl.value = u
+  document.body.style.overflow = 'hidden'
+}
+
+const closeVideoPreview = () => {
+  if (!process.client) return
+  previewVideoUrl.value = null
+  previewVideoPosterUrl.value = ''
+  previewVideoError.value = ''
+  if (!previewImageUrl.value) document.body.style.overflow = ''
+}
+
+const onPreviewVideoError = () => {
+  previewVideoError.value = '视频加载失败。'
 }
 
 const voiceRefs = ref({})
@@ -7047,9 +7105,7 @@ const openChatHistoryQuote = (rec) => {
   if (!url) return
 
   if (kind === 'video') {
-    try {
-      window.open(url, '_blank', 'noreferrer')
-    } catch {}
+    openVideoPreview(url, q?.thumbUrl)
     return
   }
 
@@ -7392,6 +7448,7 @@ const onGlobalKeyDown = (e) => {
   if (key === 'Escape') {
     if (contextMenu.value.visible) closeContextMenu()
     if (previewImageUrl.value) closeImagePreview()
+    if (previewVideoUrl.value) closeVideoPreview()
     if (Array.isArray(floatingWindows.value) && floatingWindows.value.length) closeTopFloatingWindow()
     if (chatHistoryModalVisible.value) closeChatHistoryModal()
     if (contactProfileCardOpen.value) {
@@ -9311,4 +9368,3 @@ const LinkCard = defineComponent({
   }
 }
 </style>
-
diff --git a/frontend/pages/sns.vue b/frontend/pages/sns.vue
index 3c5d121..9258c61 100644
--- a/frontend/pages/sns.vue
+++ b/frontend/pages/sns.vue
@@ -638,7 +638,19 @@
 	    >
 	      <div class="relative max-w-[92vw] max-h-[92vh] flex flex-col items-center" @click.stop>
 	        <video
-	          v-if="previewLivePhotoVideoSrc && !previewHasLivePhotoVideoError"
+	          v-if="previewIsVideo"
+	          ref="previewVideoEl"
+	          :key="previewVideoKey"
+	          :src="previewVideoSrc"
+	          :poster="previewVideoPoster"
+	          class="max-w-[90vw] max-h-[70vh] object-contain"
+	          controls
+	          autoplay
+	          playsinline
+	          @error="onPreviewVideoError"
+	        ></video>
+	        <video
+	          v-else-if="previewLivePhotoVideoSrc && !previewHasLivePhotoVideoError"
 	          ref="previewLiveVideoEl"
 	          :src="previewLivePhotoVideoSrc"
 	          :poster="previewSrc"
@@ -651,6 +663,13 @@
 	        ></video>
 	        <img v-else :src="previewSrc" alt="预览" class="max-w-[90vw] max-h-[70vh] object-contain" />
 
+	        <div
+	          v-if="previewIsVideo && previewVideoError"
+	          class="mt-3 text-xs text-red-200 whitespace-pre-wrap text-center max-w-[90vw]"
+	        >
+	          {{ previewVideoError }}
+	        </div>
+
 	      </div>
 
 	      <button
@@ -1756,6 +1775,53 @@ const previewSrc = computed(() => {
   return getMediaPreviewSrc(ctx.post, ctx.media, ctx.idx)
 })
 
+const previewVideoEl = ref(null)
+const previewVideoMode = ref('') // 'local' | 'remote' | 'raw'
+const previewVideoError = ref('')
+const previewVideoTried = reactive({ local: false, remote: false, raw: false })
+
+const resetPreviewVideo = () => {
+  previewVideoMode.value = ''
+  previewVideoError.value = ''
+  previewVideoTried.local = false
+  previewVideoTried.remote = false
+  previewVideoTried.raw = false
+}
+
+const previewIsVideo = computed(() => {
+  const ctx = previewCtx.value
+  if (!ctx) return false
+  return Number(ctx.media?.type || 0) === 6
+})
+
+const previewVideoPoster = computed(() => {
+  const ctx = previewCtx.value
+  if (!ctx) return ''
+  if (Number(ctx.media?.type || 0) !== 6) return ''
+  return getMediaThumbSrc(ctx.post, ctx.media, ctx.idx) || ''
+})
+
+const previewVideoSrc = computed(() => {
+  const ctx = previewCtx.value
+  if (!ctx) return ''
+  if (Number(ctx.media?.type || 0) !== 6) return ''
+
+  const local = getSnsVideoUrl(ctx.post?.id, ctx.media?.id)
+  const remote = getSnsRemoteVideoSrc(ctx.post, ctx.media)
+  const raw = upgradeTencentHttps(String(ctx.media?.url || '').trim())
+
+  const mode = String(previewVideoMode.value || '').toLowerCase()
+  if (mode === 'local') return local
+  if (mode === 'remote') return remote
+  if (mode === 'raw') return raw
+  return local || remote || raw || ''
+})
+
+const previewVideoKey = computed(() => {
+  if (!previewIsVideo.value) return ''
+  return `${String(previewVideoMode.value || '')}:${String(previewVideoSrc.value || '')}`
+})
+
 const previewLivePhotoVideoSrc = computed(() => {
   const ctx = previewCtx.value
   if (!ctx) return ''
@@ -1879,6 +1945,7 @@ const loadPreviewCandidates = async ({ reset }) => {
 
 const openImagePreview = async (post, m, idx = 0) => {
   if (!process.client) return
+  resetPreviewVideo()
   // Stop any background hover-playing live photo when opening the preview.
   activeLivePhotoKey.value = ''
   // Preview is an intentional action; allow retry even if hover playback failed once.
@@ -1898,11 +1965,58 @@ const openImagePreview = async (post, m, idx = 0) => {
   await loadPreviewCandidates({ reset: true })
 }
 
+const openVideoPreview = (post, m, idx = 0) => {
+  if (!process.client) return
+  resetPreviewVideo()
+  activeLivePhotoKey.value = ''
+
+  const local = getSnsVideoUrl(post?.id, m?.id)
+  const remote = getSnsRemoteVideoSrc(post, m)
+  const raw = upgradeTencentHttps(String(m?.url || '').trim())
+
+  if (local) previewVideoMode.value = 'local'
+  else if (remote) previewVideoMode.value = 'remote'
+  else if (raw) previewVideoMode.value = 'raw'
+  else previewVideoError.value = '视频地址缺失。'
+
+  previewCtx.value = { post, media: m, idx: Number(idx) || 0 }
+  previewCandidatesOpen.value = false
+  resetPreviewCandidates()
+  document.body.style.overflow = 'hidden'
+}
+
+const onPreviewVideoError = () => {
+  const ctx = previewCtx.value
+  if (!ctx) return
+  if (Number(ctx.media?.type || 0) !== 6) return
+
+  const current = String(previewVideoMode.value || '').toLowerCase()
+  if (current === 'local') previewVideoTried.local = true
+  if (current === 'remote') previewVideoTried.remote = true
+  if (current === 'raw') previewVideoTried.raw = true
+
+  // Fallback order: local -> remote -> raw
+  const remote = getSnsRemoteVideoSrc(ctx.post, ctx.media)
+  if (!previewVideoTried.remote && remote) {
+    previewVideoMode.value = 'remote'
+    return
+  }
+
+  const raw = upgradeTencentHttps(String(ctx.media?.url || '').trim())
+  if (!previewVideoTried.raw && raw) {
+    previewVideoMode.value = 'raw'
+    return
+  }
+
+  previewVideoError.value = '视频加载失败：可能是本地缓存不存在，或远程下载/解密失败。'
+}
+
 const closeImagePreview = () => {
   if (!process.client) return
   previewCtx.value = null
   previewCandidatesOpen.value = false
   resetPreviewCandidates()
+  resetPreviewVideo()
   document.body.style.overflow = ''
 }
 
@@ -1912,16 +2026,7 @@ const onMediaClick = (post, m, idx = 0) => {
 
   // 视频点击逻辑
   if (mt === 6) {
-    // Open a playable mp4 via backend (downloads+decrypts as needed).
-    const remoteUrl = getSnsRemoteVideoSrc(post, m)
-    if (remoteUrl) {
-      window.open(remoteUrl, '_blank', 'noopener,noreferrer')
-      return
-    }
-
-    // Last-resort: open raw CDN url.
-    const u = String(m?.url || '').trim()
-    if (u) window.open(u, '_blank', 'noopener,noreferrer')
+    openVideoPreview(post, m, idx)
     return
   }