I love the application but the CSS drives me nuts.

Some suggestions

Use ID instead of class at the template level and page level so we can eliminate a lot of the nesting and eliminate a lot of classes and make it much more readable.

#Global (at the template)

(Page level)
#Page_Products
#Page_Categories
#Page_Topic  etc.

Instead of Classes for the headings it would be preferable to use H1 for page headings or at least

#Global H1{}
#Global H2{}
#Global p{}

You can overide at the page level.

Example:

<html>

<style>

#Global H1{Font-size:20pt}
#Global H2{color:green}

#Page_Products H1{Font-size:15pt; color:red}

</style>


<div id="Global">


  <h1>Test Global Heading</h1>
  <h2>Test H2 Global</h2>

<div id="Page_Products">

  <h1>Test Page_Products Heading</h1>
  <h2>Test H2 Page_Products</h2>


<div>


</html>

Just some food for thought