It's a little hard to say without knowing more about your web application.
First, are you sure you really want to do this? One of your “many developers” can change the stylesheet, expecting it to affect only one application and affect others. Things can turn out to be even more messy when you need to create stylesheets for each application that override things in general, etc. I would consider these potential potential side effects before continuing this.
, - <link> @import. , "". , , - http://shared.whatever.com/css/styles.css.