[Victor D]

In skin1.css

HTML, BODY{
background: #a5070d url(images/mybg.gif) left top repeat-x;
}
TABLE.Container{
background-color: #fff;
}

if there is no need to attach image

HTML, BODY{
background-color: #a5070d;
}
TABLE.Container{
background-color: #fff;
}

also there are two gradients by the table side
you may need to add two extra rows wrapping TD.Container in rectangle_top.tpl for them
(and not to forget to close them in rectangle_bottom.tpl)