<a href="#" class="cp_btn">button</a>
a.cp_btn {
display: flex;
align-items: center;
justify-content: center;
width: 120px;
height: 120px;
text-decoration: none;
color: #FF5722;
border: double 4px #FF5722;
border-radius: 50%;
transition: .6s ease-in-out;
}
a.cp_btn:hover {
transform: rotateY(360deg);
}