.bandera {
    height: 40px;
    width: 250px;
    margin: 0.5rem;
}
.argentina {
    background: linear-gradient(to bottom, #75AADB 33%, #fff 33%, #ffffff 66%, #75AADB 66%);
    background: -webkit-linear-gradient(top, #75AADB 33%, #fff 33%, #ffffff 66%, #75AADB 66%);
}
.btn-whatsapp {
    display:block;
    width:70px;
    height:70px;
    color:#fff;
    position: fixed;
    right:15px;
    bottom:80px;
    border-radius:50%;
    line-height:80px;
    text-align:center;
    z-index:999;
}
.centrar{
    text-align: center;
    display: flex;
    justify-content: center;
}

#navigation ul a:hover {
    display: block;
    color: red;
    text-decoration: none;
}