<html><head><meta name="viewport" content="width=device-width, initial-scale=1.0"><style>video { max-width: 100%; height: auto;}</style></head><body><video width="400" controls> <source src="/i/photo/shanghai.mp4" type="video/mp4"> Your browser does not support HTML5 video.</video><p>请调整浏览器窗口的大小，查看宽度小于 400 像素时视频播放器如何缩放。</p></body></html>