.art_yt {

    position: relative;

    display: block;

    margin-bottom: 20px;

    padding-bottom:56.25%;

    padding-top:30px;

    height:0;

    overflow:hidden;

}

.art_yt  iframe,

.art_yt  object,

.art_yt  embed {

    position:absolute;

    top:0;

    left:0;

    width:100%;

    height:100%;

}

.ivs-left {

    text-align: left

}



.ivs-center {

    text-align: center

}



.ivs-right {

    text-align: right

}



.ivs-none {

    display: none

}