Here's a few changes I noted to get rid of some of the borders and other shadowed images. The I've also included what I think may be the list of images to change to get the gradient you're looking for through the middle of the page.
Main Body getting rid of main content area background to use only the overall background for the body and getting rid of the border
Change in template.css (line 123) to this:#smoke .sections td, #smoke #mainframe td#left, #smoke #mainframe td#right, #smoke #mainframe #user1, #smoke #mainframe #page, #smoke pre, #smoke blockquote, #smoke .sectiontableheader {
background:transparent none repeat scroll 0 0;
border:0 none;
}
Then change in fest (line 34) to this:.sections td, #showcase, #mainframe td#left, #mainframe td#right, #mainframe #user1, #mainframe #page, pre {
border:0 solid #364148;
}
Then getting rid of the left and right borders in the main menu, change the following in header-d...-teal.css (line 5) to this:#horiz-menu {
background:transparent url(../images/headers/dark-teal/header-bg.png) repeat-x scroll 0 0;
border-left:0px solid #304B53;
border-right:0px solid #304B53;
}
Then I guess you may need to change the following images:
../images/smoke/shadow-m.png
../images/smoke/shadow-t.png
../images/smoke/shadow-b.png
../images/smoke/shadow-rocket.png