body {
    margin: 0;
    padding: 0;
    color: rgba(255, 255, 255, 0.87);
    background-color: #000000;
}

#app {
    width: 90%;
    height: 50%;
    overflow: hidden;
    display: flex;
    justify-content: center;
    align-items: center;
    margin: 50px auto;
}