drop shadow on main container

hi - i wanted a drop shadow on the main container and i've come up with a way of doing it - just wondering if anyone sees anything wrong with this - i ask because i have used what appears to be a redundant div to do it and i hope i'm not messing with the machinery of this pretty complex theme.

as i said the div (#wrapper ) appears to be redundant however i suspect that it may be just that it's used in fluid width setups in the max min width area - i have no experience of how atahualpa achieves this but maybe someone could confirm this for me

the problem is that i wanted 3 backgrounds - one for the body background, one for the site itself and a third as a drop shadow around the container - i managed to do the first 2 in the theme options but i needed a div to put the drop shadow into

the container was "contained" by #container and #wrapper so what ive done is to give #wrapper a padding and a background which contains the drop shadow effect

i added this to the css inserts section of atahualpa

#wrapper{
padding-left:20px;
padding-right:20px;
background: url(../self-catering-images/dropshadow.png) repeat-y;
}

i post this here in case a) maybe it's a bad practice b) maybe there's a better way and c)maybe it might be a way to put a drop shadow on a site in atahualpa which i havent seen on the forums

thanks