Kuroi, thank you for your help. I can't believe that I missed the x-repeat dislexic move on my part :blush: .
As far as the mainwrapper div being too short, unfortunately this is not the problem. You have a good eye and it is only 780px, but I dropped a table around the outside of my entire shop in the tpl_main_page, added 3 <td> elements, with the middle containing all of the shop code, and the outer two with the shop borders. This was the best way I could come up with, although I'm sure there is probably a more efficient way to do it with css.
So I'm stumped (like I said, I'm a beginner with much of this css stuff). Curiosly the three spaces all fall directly under div that are doing the same thing with essentially the same coding pattern.
For example, the very top space is right below the <div> whose sole purpose is to house the image for the top of the tabs (the header navigation):
#navTab {
height:20px;
width:780px;
float:left;
background-image: url(../images/header/header-tab-background.gif);
background-repeat: repeat-x;}
What shows up on the html side is:
<div class="navTab-top"></div>
The others do the same thing
#navTab-bottom {
background-image: url(../images/header/header-tab-bottom.gif);
background-repeat: repeat-x;
height:8px;
width:780px;
float:left;}
<div id="navTab-bottom"></div>
#search-bg {
background-image: url(../images/search-bg.gif);
background-repeat: repeat-x;
height:30px;
width:780px;
float:left;}
<div id="search-bg"></div>
Is this an incorrect way to code?