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

#gameCanvas {
    position: fixed;
    inset: 0;
    width: 100vw;
    height: 100vh;
    display: block;
    background-image: url('/images/Game Images/background.jpg');
    background-repeat: no-repeat;
    background-position: center;
    background-size: cover;
}