Hi,
Make sure it is not a caching issue as discussed here:
http://www.mojoportal.com/skinning-overview.aspx
What you need to know before you start editing a skin
The first thing that most people stumble on is that they make a change to the css in a skin and they do not see any change in the browser. This is because the CSS is cached both on the server and in the browser by default for best performance on production sites. So the first thing you need to do is disable caching while you are working on the design. To do that, add these entries to your user.config file:
<add key="CacheCssOnServer" value="false" />
<add key="CacheCssInBrowser" value="false" />
After adding those settings you need to touch Web.config to make it reload settings because it does not automatically detect changes in user.config, but it does automatically detect changes in Web.config, so you just type a space in Web.config and save it. After making these changes you still may need to clear your browser cache one time.
When you are finished with your skin you should turn caching back on for best performance. Note that since visitors to your site may already have cached the old version of CSS, the easiest way to be sure all visitors will see the new changes in the skin is to copy the skin and give it a new name like yourskin_v2 and then set the site to use the new copy of the skin. Since the name of the skin changed, the path for the css also changes and this means all visitors will load the new CSS on their next visit because the caching is base don the url and this makes the url change.
Hope it helps,
Joe