.loader{animation:effect 1s linear infinite;width:30px;height:30px;border-radius:50%;border:4px solid rgba(44,44,44,.3);border-top-color:#fff}@keyframes effect{0%{transform:rotate(0deg)}to{transform:rotate(1turn)}}.btn{position:relative}.btn .loader{position:absolute;top:50%;left:50%;margin-top:-20px;margin-left:-20px;width:40px;height:40px;border:5px solid rgba(44,44,44,.3);border-top-color:#fff}