body{align-items:center;display:flex;height:100vh;justify-content:center;overflow:hidden;width:100vw}#bigRedBtn{background-color:red;border:none;border-radius:60px;box-shadow:0 4px 8px rgba(0,0,0,.2);color:#fff;cursor:pointer;font-size:1.2rem;height:120px;transition:background-color .3s ease;width:120px}#bigRedBtn:hover{background-color:darkred}