Ruby on Rails

Hello all,

I have been struggling all day with getting css files to load in my application. I am attempting to use the rails-ui-themes gem to help style my application but right now just getting simple css code to render is not working. 

I have tried removing the require_tree and including the file individually and it still does not seem to work.  When I look at the source of my html, every css file is loaded including the application.css file but nothing seems to happen.

I was wondering if anyone can tell me what I am missing. 

At this moment here is what I have as my configuration:

app/assets/stylesheets/application.css:

 *= require_self

 *= require_tree .

 *= require jquery-ui/overcast

layouts/application.html.erb:

  <%= stylesheet_link_tag    "application", :media => "all" %>

  <%= javascript_include_tag "application" %>

some css I have tried to render:

<div class='ui-corner-all'>

.....

</div>

or 

<div id='user_nav'>

....

</div>

The simple css that I tried to render is

#user_nav{

float: right;

font-size: 12px;

}