首先 第一次Github <title>引导程序示例</ title> [removed] #fullwidth-video{ height: 50vw; min-height:50vh; position: relative; } #fullwidth-video .fullwidth-video-bg { position: absolute; z-index: 1; top: 0px; left: 0px; bottom: 0px; right: 0px; overflow: hidden; background-size: cover; background-color: transparent; background-repeat: no-repeat; background-position: