body {
    background: url("https://media.8ch.net/stylesheets/img/fade-blue.png") repeat-x scroll 50% 0% #EEF2FF;
    color: #000;
    font-family: arial,helvetica,sans-serif;
    font-size: 10pt;
    margin: 0px 4px;
    padding-left: 4px;
    padding-right: 4px;
}

body::after {
    position: fixed !important;
    content: url("https://i.imgur.com/2QdIPla.jpg");
    bottom: -20px;
    right: 20px !important;
    opacity: 1;
    z-index: -1;
}