html, body {
    width: 100%;
    height: 100%;
}
body {
    background-color: #555555;
    margin: 0;
    overflow: hidden;
    font-family: arial;
}

#container {
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
}

#overlay {
    position: absolute;
    background-color: rgba(0,0,0,0.1);
    display: flex;
}

#instructions {
    flex: 1;
}

#renderer {
    position: relative;
}