iframe.ytVideo {
    width: 700px;
    height: 394px;
    border: 3px solid #464242;
}
div.mediaContainer span {
    width: 700px;
}
@media only screen and (max-width: 710px)  {
    iframe.ytVideo {
        width: 500px;
        height: 281px;
    }
    div.mediaContainer span {
        width: 500px;
    }    
}
@media only screen and (max-width: 510px)  {
    iframe.ytVideo {
        width: 300px;
        height: 169px;
    }
    div.mediaContainer span {
        width: 300px;
    }    
}
@media only screen and (max-width: 310px)  {
    iframe.ytVideo {
        width: 200px;
        height: 113px;
    }
    div.mediaContainer span {
        width: 200px;
    }    
}