html, body {
    height: 100%;
    margin: 0;
 }

body {
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    background-color: #f9f9f9;
    font: normal 1em / 1.5em BlinkMacSystemFont, -apple-system, 'Segoe UI', roboto, helvetica, arial, sans-serif;
 }

h1 {
    padding: 1em 0;
    margin: 0;
    font-size: 1.25em;
    color: #555;
    text-align: center;
    text-transform: uppercase;
    letter-spacing: 2px;
 }

div {
    width: 80%;
    max-width: 30em;
    padding: 0.5em;
    border: 0.25em double #999;
    background-color: #fff;
    box-shadow: 0 0 0.75em rgba( 0, 0, 0, 0.4);
    font-size: 1.5em;
    font-weight: bold;
    color: #999;
    text-align: center;
 }