body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    margin: 0;
    padding: 20px;
    background-color: #fffff;
}

#app {
    width: 100%;
    max-width: 600px;
    min-width: 400px;
    height: 400px;
    border: none;
    margin: 0 auto;
    display: block;
}