html {
    background-color: lightgray;
}
body {
    width: 400px;
    height: 410px;
    margin: 0 auto;
    background-color: white;
    padding: 20px;
    border: 5px solid black;
}
div{
    width: 400px;
    height: 400px;
    border: 1px solid black;
    border-radius: 200px;
}