@media only screen and (min-width: 800px) {
   
    .external{
        width:20%;
        margin:auto;
        margin-top:5%
    }
    
    }
    
    @media only screen and (max-width: 800px) {
    
        .external{
            width:50%;
            margin:auto;
            margin-top:5%
        }
    
    }