transparent theme

My blog http://www.otakixus.net/blog

I’m trying to make the theme go transparent but I can’t seem to do that. I’ve saved it with .gif and .png at 80% transparent on both ends. The code is this:

#wrapper { width:1000px; margin:0 auto; }
#header { background:url(img/header.png) no-repeat bottom; }
#contents { background:url(img/side.gif) repeat-y; }
#left_col { float:left; display:inline; width:760px; margin:0 0 0 2px; }
#right_col { float:right; display:inline; width:236px; margin:51px 2px 30px 0; }
#footer { background:url(img/footer.gif) no-repeat top; height:90px; }

The .png formats were originally .gif. I have two separate folders. First one goes into /img and the other one is /img/width_930px for the current theme. I’ve played around with both but I still can’t get a single thing in the theme to be transparent. Is there a code I need to put to actually make it transparent or am I missing something? The image in the background is a sample I uploaded just for a while until I get this thing working.