Issue #2054: Remove empty CSS rule

Fixes `Rule is empty` inspection violations.

Description:
>An empty rule is one that doesn't contain any properties, such as:
 ```
  .foo {
  }
```
A lot of times, empty rules appear as a result of refactoring without further cleanup. Eliminating empty rules results in smaller file sizes and less style information for the browser to deal with.

src/site/resources/css/site.css

@@ -37,10 +37,6 @@ h4 {
   background: url("../images/header-background.png") repeat scroll 0 0 transparent;
 }
 
-.section {
-
-}
-
 a.dl-link {
   position: relative;
   float: right;