@media only screen and (max-width: 574px) {
    #bn01 {
        background-image: url(/Content/images/mc-fachada-mobile-5.png)
    }
}

@media only screen and (min-width: 575px) {
    #bn01 {
        background-image: url(/Content/images/mc-fachada-mobile-4.png)
    }   
}

@media only screen and (min-width: 670px) {
    #bn01 {
        background-image: url(/Content/images/mc-fachada-mobile-3.png)
    }
}

@media only screen and (min-width: 691px) {
    #bn01 {
        background-image: url(/Content/images/mc-fachada-mobile.png)
    }  
}

@media only screen and (min-width: 1150px) {
    #bn01 {
        background-image: url(/Content/images/fachada_mc_imoveis_recortada.jpg)
    }   
}

.whatsbtn {
    position: fixed;
    width: 60px;
    height: 60px;
    bottom: 25px;
    right: 70px;
    background-color: #25d366;
    color: #FFF;
    border-radius: 50px;
    text-align: center;
    font-size: 30px;
    box-shadow: 1px 1px 2px #888;
    z-index: 1000;
    color:#fff;
}

.whatsbtn :hover{
     color:#fff;
}