function mainmenu(){
$(" #nav_menu ul ").css({display: "none"}); // Opera Fix
$(" #nav_menu li").hover(function(){
    $(this).find('ul:first').css({visibility: "visible",display: "none"}).show(300);
    $(this).find('a:first').css({"font-weight":"bold","border-color":"#959cbc","color":"#fff","background-color":"rgb(41,105,165)" });
},function(){ $(this).find('ul:first').css({visibility: "hidden"});
$(this).find('a:first').css({"font-weight":"bold","border-bottom-color":"#959cbc","color":"#fff", "background-color":"rgb(40,84,131)"  });
});
}
$(document).ready(function(){                                                                                
    mainmenu();
});