.li-whatsapp a {

width: 52px!important;
height: 52px!important;
}

.li-whatsapp i {
font-size: 40px!important;

}

@media (max-width: 767px){
.li-whatsapp a {

width: 42px!important;
height: 42px!important;
}

.li-whatsapp i {
font-size: 30px!important;

}
}