#ifdef XP_WIN
.noWin, .mac, .unix { display: none; } 
#else
#ifdef XP_MACOSX
.noMac, .win, .unix { display: none; }
#else
#ifdef XP_OS2
.noWin, .mac, .unix { display: none; }
#else
.noUnix, .win, .mac { display: none; }
#endif
#endif