.nav_bg {  background-attachment: scroll; background-image: url(images/nav_bg.jpg); background-repeat: no-repeat; background-position: center top}
.lines {  background-attachment: fixed; background-image: url(images/about_bg.jpg); background-repeat: no-repeat; background-position: center top}
.news_bg {  background-attachment: scroll; background-image: url(images/main_bg_01.jpg); background-repeat: no-repeat; background-position: center top}