<a href="#" class="link">Smooth Hover</a>
.link{
text-decoration: none;
color: inherit;
background: white;
padding:10px 15px;
border-radius: 7px;
transition: 0.15s ease-in-out;
box-shadow: 0 1rem 3rem rgba(0,0,0,.175)!important;
}
.link:hover{
background:purple;
color: white;
}