Is it normal ? Do i have to build and install the WOApp in a real
deployment way ? Any clue ?
No, you don't have to install your app. You have to make sure, that:
1. The path you give in your html is based on the webserver root
directory. This is normally /Library/WebServer/Documents on Mac OS X.
So you can refer to a css file that is in this directory with
href="/styles.css"
2. Make sure, the webserver user can access the stylesheet file
(permissions). If you have only a symlink in the webserver dir, the
whole path has to be readable by the webserver user (www).
3. I don't remember what the default is, but the apache webserver must
be allowed to follow symlinks (in the directory settings for the
default domain in the httpd.conf).