#conteneur3d {
    position: static;
    margin-right: 28%;
    height: 100vh;
    overflow-y: hidden;
}
main {
    position: relative;
    overflow: hidden;
}

#kuipanel {
    position: absolute;
    top: 0;
    right: 0;
    width: 28%;
    height: 100%;
    overflow-y: auto;
    background-color: rgb(247, 248, 250);
}

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

#retour {
    position: absolute;
    bottom:0;
    right: 45%;
    margin-left: -50%;
    border-radius: 6px 6px 0 0;
    /*background: linear-gradient(180deg, rgba(255,255,255,1) 0%, rgba(224,224,224,1) 100%);*/
    border-color : rgb(206, 205, 205);
    border-width:1px;
    border-style: solid;
   /* height: 30px;*/

}
#overlay {
    background: #ffffff;
    color: #666666;
    position: fixed;
    height: 100%;
    width: 100%;
    z-index: 5000;
    top: 0;
    left: 0;
    float: left;
    text-align: center;
    padding-top: 25%;
    opacity: .80;
  }

/************** responsive ***********/

@media screen and (max-width: 1100px) {
    #kuipanel  {
      width: 40%;
    }
    #conteneur3d {
        margin-right: 40%;
    }
  }