Background Colour - Featured Productsting on Main Page

Hi, I am very new to zencart and trying to dramatically modify the classic template v 1.5. However I cant seem to do it. What I have managed to do is remove the background behind the title heading and now I want it back. I am modifyng Stylesheet CSS. I have tried a number of area's and cant work it out! The area I thought it was is h2.CentreBoxHeading or centreboxwrapper or centreboxcontents(although prob not)! When I modify h2.CentreBoxHeading I can get the text alignment to change on the heading name, so I think its this, but cant get that 1cm background I want with colour behind it. I am not sure if I am in the wrong spot or adding the wrong attributes to achieve it. I have also managed to remove this for the product listing heading background also (in the process).
Code is
h2.centerBoxHeading {
font-size: 16px;
color: 9DDCF9;
}
.centerBoxWrapper {
height: 1%;
border: 1px solid #9a9a9a;
margin: 1.1em 0;
}
.centerBoxContents, .specialsListBoxContents, .categoryListBoxContents, .additionalImages, .centerBoxContentsSpecials, .centerBoxContentsAlsoPurch, .centerBoxContentsFeatured, .centerBoxContentsNew {
margin: 1em 0em;
color: #F00;
padding-bottom: 1cm;
}
.productListing-rowheading {
background-color: 9DDCF9;
height: 3em;
color: 9DDCF9;
margin: 20 cm;
border: 2 cm;
}
Link to my cart (which isnt live hence the long name is )
http://www.simplistyleparties.com.au/Shopping%20Cart/zen-cart-v150-full-release-12302011/

thanks to anyone that can help.....

First, stop everything and create your custom template and make your edits there.

http://www.zen-cart.com/content.php?180-how-do-i-create-a-new-custom-template

Changing the stylesheet on your site using Web Developer, this does work for me (if I understand what you're trying to do):

h2.centerBoxHeading {
font-size: 16px;
color: 9DDCF9;
background-color: #ff0000;
}