*{
    margin:0;
    padding: 0;
}

body{
    height: 100vh;
    background: #ffffff url(../img/intro-bg.jpg);
    background-repeat: no-repeat;
    background-size: contain;
    background-position: center;
    display: flex;    
    justify-content: center;
    align-items: center;
}

#main-img{
    margin: 0;
    width: 85%;
}

#main-img img{
    width: 100%;
}

@media all and (min-width:768px){
    #main-img{
        width: unset;
    }    
}