.youtube_preview {
    position: relative;
    width: 640px;
    top: 0;
    left: 0;
    bottom: 0;
    max-width: 100% !important;
    border: 0;
    background: url('../img/yt_logo_rgb_dark.png') no-repeat center center;
    background-size: cover;
    background-repeat: no-repeat;
    background-color: grey;
    text-align: center;
    vertical-align: bottom;
    display: table-cell;
}

.youtube_preview .text {
    background-color: rgba(0,0,0,0.5);
    color:#fff;
    padding: 10px;
}