button{transition:all .3s ease}button.loading{background:#ccc;color:#fff;animation:spin 1.5s linear infinite}@keyframes spin{0%{transform:rotate(0)}to{transform:rotate(360deg)}}button.sent{background:#4caf50;color:#fff;animation:fadeIn .5s ease-in-out}@keyframes fadeIn{0%{opacity:0;transform:scale(.8)}to{opacity:1;transform:scale(1)}}