body{margin:0;background:cyan;min-height:100vh;display:flex;align-items:center;justify-content:center;transition:.25s ease-in-out}button{background-color:#212121;color:#fff;padding:1rem 1.5rem;font-size:18px;border:none;cursor:pointer;letter-spacing:0.5px;border-radius:3rem;animation:bounce 1s infinite ease-in-out;transition:transform .3s;position:relative;z-index:1;&:before{position:absolute;content:'';left:-6px;top:-6px;width:100%;height:100%;margin:0;border-radius:inherit;background-color:transparent;border:6px solid rgba(255,255,255,.2);box-shadow:2px 2px 14px rgba(0,0,0,.2);transition:.3s}&:hover{animation:none}&:active{transform:scale(.9375);&:hover{box-shadow:2px 2px 24px rgba(0,0,0,.2)}}}@keyframes bounce{50%{transform:scale(.9375)}}