No need for the specificity .navbar-default
in your CSS. Background color requires background-color:#cc333333
(or just background:#cc3333
). Finally, probably best to consolidate all your customizations into a single class, as below:
.navbar-custom {
color: #FFFFFF;
background-color: #CC3333;
}
..
<div id="menu" class="navbar navbar-default navbar-custom">
Example: http://www.bootply.com/OusJAAvFqR#