.youtubevideomodal{width:1200px;max-width:100%;margin:20px auto}
.iframe-modal{border:0 soid transparent;width:100%;height:540px;max-width:955px;margin:auto;display:block}
@media only screen and (min-width:320px) and (max-width:767px){.iframe-modal{width:100vw;height:calc(100vw/1.77)}
}