Two questions about CSSing inside the menus

If you want your navigation span element to be a block, instead of inline element, just target it via css

nav > ul > li > a > span{
    display:block;
}

This is providing your HTML structure looks something like this:

<nav>
    <ul>
        <li>
            <a href="#" class="menu-link">
                <span>Home</span>
            </a>
        </li>
        <!-- other list elements go here -->
    </ul>
</nav>

Hope this helps.