@-moz-document regexp("^about:(newtab|home)") {
body{
    background-image: url('https://avatanplus.com/files/resources/mid/56c610b63d727152f5b147ec.png')!important;
    background-size: 20%!important;
    background-repeat: no-repeat!important;
    background-position: right bottom!important;
    background-attachment: fixed!important;
  }
}