.nav {
    left: 50%;
    margin-left: -150px;
    top: 50px;
    position: absolute;
}

    .nav > li > a:hover, .nav > li > a:focus, .nav .open > a, .nav .open > a:hover, .nav .open > a:focus {
        background: #fff;
    }

.dropdown {
    background: #fff;
    border: 1px solid #ccc;
    border-radius: 4px;
    width: 300px;
}

.dropdown-menu > li > a {
    color: #428bca;
}

.dropdown ul.dropdown-menu {
    border-radius: 4px;
    box-shadow: none;
    margin-top: 20px;
    width: 300px;
}

    .dropdown ul.dropdown-menu:before {
        content: "";
        border-bottom: 10px solid #fff;
        border-right: 10px solid transparent;
        border-left: 10px solid transparent;
        position: absolute;
        top: -10px;
        right: 16px;
        z-index: 10;
    }

    .dropdown ul.dropdown-menu:after {
        content: "";
        border-bottom: 12px solid #ccc;
        border-right: 12px solid transparent;
        border-left: 12px solid transparent;
        position: absolute;
        top: -12px;
        right: 14px;
        z-index: 9;
    }