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