Here is the style for this block in template_css.css
#ja-topslwrap, #ja-botslwrap {
background:#FF0F0F url(../images/corner-black-tl.gif) no-repeat scroll left top;
}
#ja-topslwrap #ja-topsl, #ja-botslwrap #ja-botsl {
background:transparent url(../images/corner-black-tr.gif) no-repeat scroll right top;
}
#ja-topsl div.ja-wrap1, #ja-botsl div.ja-wrap1 {
background:transparent url(../images/corner-black-bl.gif) no-repeat scroll left bottom;
}
#ja-topsl div.ja-wrap2, #ja-botsl div.ja-wrap2 {
background:transparent url(../images/corner-black-br.gif) no-repeat scroll right bottom;
padding:5px 0pt;
}