.box{
    height:200px;
    width:200px;
    border:3px solid #aaa;
    margin:50px auto;
    border-radius: 50%;
    box-shadow: 0 0 5px #000;
    position: fixed;
    left:40%;
    top:100px;
    background: #57cdf9;
    opacity:0.7;
}