Вопросы по CSS

$(document).ready(function(){

    $('.dropdown>span').on('click', function(){
        $(this).next('div').toggle();
    });

});

<div class="dropdown">
            <span>Menu</span>
            <div>
                <a href="#">link1</a>
                <a href="#">link2</a>
                <a href="#">link3</a>
                <a href="#">link4</a>
            </div>
        </div>

div.dropdown {
    float: right;
    font-size: 20px;
    font-weight: normal;
    width: 120px;
    text-align: center;
    z-index: 10;
}

div.dropdown>span {
    display: block;
    padding: 5px;
    cursor: pointer;
    background: #000000;
}
div.dropdown>div {
    background: #333;
    display: none;
}
div.dropdown>div>a {
    display: block;
    color: #FFFFFF;
    font-size: 15px;
    padding: 3px;
    text-align: center;
    border-top: 1px solid #000000;
}