.btn-tienda{
    position:fixed;
    width:60px;
    height:60px;
    line-height: 63px;
    /* mover boton*/
    bottom:247px;
    right:25px;

    background:#ff0000;
    color:#ffffff;
    border-radius:50px;
    text-align:center;
    font-size:35px;
    box-shadow: 0px 1px 10px rgba(0,0,0,0.3);
    z-index:100;
    transition: all 300ms ease;
}
.btn-tienda:hover{
    background: #ffffff;
     color:#ff0000;
     
     width:70px;
    height:70px;
    line-height: 73px;
    /* mover boton*/
    bottom:257px;
    right:35px;
}
@media only screen and (min-width:320px) and (max-width:768px){
    .btn-tienda{
        width:63px;
        height:63px;
        line-height: 66px;
    }
}