diff --git a/deploy/web/default.conf b/deploy/web/default.conf
index 1e7cb26..6da25f6 100644
--- a/deploy/web/default.conf
+++ b/deploy/web/default.conf
@@ -17,6 +17,12 @@ server {
     add_header Cache-Control "public, immutable";
   }
 
+  # 推广素材：文件必须真实存在，禁止落到 SPA index.html（否则前端误判「静态存在」、视频拿到 HTML）
+  location ^~ /promotion/ {
+    try_files $uri =404;
+    add_header Cache-Control "public, max-age=86400";
+  }
+
   location = / {
     try_files /index.html =404;
   }
diff --git a/nginx/web.conf b/nginx/web.conf
index 3fd038b..f5ffd8c 100644
--- a/nginx/web.conf
+++ b/nginx/web.conf
@@ -15,6 +15,11 @@ server {
         add_header Cache-Control "public, immutable";
     }
 
+    location ^~ /promotion/ {
+        try_files $uri =404;
+        add_header Cache-Control "public, max-age=86400";
+    }
+
     location = / {
         try_files /index.html =404;
     }
diff --git a/web/src/data/promotionVideos.js b/web/src/data/promotionVideos.js
index 537f0aa..55cbcb7 100644
--- a/web/src/data/promotionVideos.js
+++ b/web/src/data/promotionVideos.js
@@ -44,8 +44,20 @@ export const PROMOTION_VIDEOS_BASE = [
   }
 ]
 
+function responseLooksLikeSpaHtml(res) {
+  const ct = (res.headers.get('content-type') || '').toLowerCase()
+  return ct.includes('text/html')
+}
+
+function responseIsUsableAsset(res) {
+  if (res.ok) return !responseLooksLikeSpaHtml(res)
+  return res.status === 206
+}
+
 /**
- * 检测同域静态 /promotion/ 文件是否可访问（优先 HEAD，405 时用 Range GET）
+ * 检测同域静态 /promotion/ 文件是否真实存在。
+ * - 需配合 Nginx：`location ^~ /promotion/ { try_files $uri =404; }`，避免缺失时返回 index.html 误判为 200。
+ * - HEAD 非 2xx 或疑似 SPA 回退时，再用 Range GET 探测（部分环境对 .mov 的 HEAD 不友好）。
  * @param {string} url
  * @returns {Promise<boolean>}
  */
@@ -57,18 +69,18 @@ export async function promotionStaticUrlExists(url) {
       credentials: 'same-origin',
       cache: 'default'
     })
-    if (head.ok) return true
-    if (head.status === 405) {
-      const r = await fetch(url, {
-        method: 'GET',
-        headers: { Range: 'bytes=0-0' },
-        mode: 'same-origin',
-        credentials: 'same-origin',
-        cache: 'default'
-      })
-      return r.ok || r.status === 206
-    }
-    return false
+    if (head.ok && !responseLooksLikeSpaHtml(head)) return true
+
+    const r = await fetch(url, {
+      method: 'GET',
+      headers: { Range: 'bytes=0-0' },
+      mode: 'same-origin',
+      credentials: 'same-origin',
+      cache: 'default'
+    })
+    if (!responseIsUsableAsset(r)) return false
+    if (responseLooksLikeSpaHtml(r)) return false
+    return true
   } catch {
     return false
   }