Update style/Air.css

Fix icon post on https://fluxbb.org/forums/search.php?action=show_user_posts&user_id=157
before 
http://zapodaj.net/images/074f72a508585.png
after fix 
http://zapodaj.net/images/99c7ed08421c9.png
This is important in the styles in which we add the code instead of images. In general, the devil icon post here?