body {
    background-image: url(https://derpicdn.net/img/2017/8/23/1517875/full.jpeg);
    background-position: center top;
    background-attachment:fixed;
    background-size:100% 100%;
}
#home {
    box-shadow: 0 2px 6px rgba(100, 100, 100, 0.3);
    opacity: 0.8;
}