#bgvid {  
            margin: 0px;  
            padding: 0px;  
        }  
        video{  
            position: fixed;  
            right: 0px;  
            bottom: 0px;  
            min-width: 100%;  
            min-height: 100%;  
            height: auto;  
            width: auto;  
            /*加滤镜*/
            /*filter: blur(15px); //背景模糊设置 */
            /*-webkit-filter: grayscale(100%);*/  
            /*filter:grayscale(100%); //背景灰度设置*/  
            z-index:-11
        }  
        source{  
            min-width: 100%;  
            min-height: 100%;  
            height: auto;  
            width: auto;  
        }

    
#login_frame {
    width: 750px;
    height: 510px;
    padding: 13px;

    position: absolute;
    left: 50%;
    top: 50%;
    margin-left: -388px;
    margin-top: -268px;

    background-color: rgba(240, 255, 255, 0.5);

    border-radius: 10px;
    text-align: center;
}