.iframe-wrapper {
    position: relative;
    padding-bottom: 56.25%;
    height: 0;
    overflow: hidden;
  }
  
.iframe-wrapper iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
  }

/*堀　MRD*/
.iframe-mrd {
    position: relative;
    padding-bottom: 61.5%;
    height: 0;
    overflow: hidden;
  }
  
.iframe-mrd iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
  }
/*堀　YouTubeレスポンシブ*/
  .youtube { 
    position: relative;
    padding-top: 56.25%;
    }
    .youtube iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    }
    @media screen and (min-width:768px) {
      .youtube {
        position: static;
        padding-top:0;
        text-align: center;
      }
      .youtube iframe {
        position: static;
        width: 560px;;
        height: 315px;
      }
    }