html {
    height: 100%;
    overflow: hidden;
}

body {
    background-image: url('https://bluemoonrise.net/bg.png');
    background-size: cover;
    background-position: center;
}

.img {
    background-image: url('https://bluemoonrise.net/download.png');
    margin: 15% auto;
    width: 552px;
    height: 300px;
}