The next obvious area for you to begin to customize is the primary content area (that is, the section between your store's header and footer). Your first task is to style the areas to match more closely the header area you have just customized. At present, the content area will look much like the following:
Take a look at the structure of the HTML of this area of your store. You will see that it is basically structured like the header of your store was, with a
.main-container element spanning the full width and height of the content area and a
<div> with the class
.main used as a wrapper around all of the content, ...