body {
    font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
    text-align: center;
}

.center {
    margin: auto;
    position: absolute;
    top: 0; left: 0; bottom: 0; right: 0;
    width: 50%;
    height: 50%;
    min-width: 200px;
    max-width: 400px;
    padding: 40px;
}

.circle-image {
    width: 200px;
    height: 200px;
    border-radius: 100%;
    display: block;
}
