#cnblogs_post_body .video{
    height: 0;
    padding-bottom: 56.25%;  /* 16:9 */
    position: relative;
    width: 100%;
}

#cnblogs_post_body .video iframe{
position: absolute;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
}