.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
    }