Use CSS to keep the top-level navigation hover eff

Question

When you mouseover a navigation item, the colour of the link changes to white and background of that link goes black. The hover state does a display:block on a hidden nested . When I move the mouse over to the nested (i.e. the sub menu), the hover state on the top-level nav returns back to the way it was. How do I make it persist whilst my mouse is over the sub-menu?

In other words, when I hover the link 'What we do', the font color changes to #fff and background to #111 and the ul.sub-menu appears with the same black background and white text. This all appears whilst my mouse hovers over 'What we do', but as soon as it moves to the sub-menu, the background on 'What we do' returns to its original color and font color changes back to black. Meanwhile my sub-menu remains open in the correct format. How do I get the 'state' to persist when I move the mouse hover away?

Here is a jsfiddle for it: http://jsfiddle.net/U77re/

nav ul#menu-top-nav { position: absolute; top: 35px; left: 113px; padding: 16px 30px 17px 20px; width: 797px; background: #F0F1F4;}
nav ul#menu-top-nav li { position: relative; float: left; margin: 0 40px 0 0; }
nav ul#menu-top-nav li a:hover { color: #fff; background: #111;  }
nav ul#menu-top-nav li#menu-item-1186 { margin-right: 0; }
nav ul#menu-top-nav ul.sub-menu { display: none; }
nav ul#menu-top-nav ul.sub-menu li a { margin: 0; }

nav ul#menu-top-nav li:hover ul.sub-menu { display: block; position: absolute; left:0; top: 30px; width: 250px; padding: 20px;
                                    z-index: 1; background: #111; }

nav ul#menu-top-nav  ul.sub-menu p { margin: 0 0 25px 0; color: #fff; line-height: 1.4; font-weight: bold; }
nav ul#menu-top-nav  ul.sub-menu li { width: 250px; margin: 0 0 20px 20px; color: #fff; list-style-position: inside; list-style-type: disc;  }
nav ul#menu-top-nav  ul.sub-menu li a { color: #fff;  }

<nav role="navigation">
    <ul class="menu" id="menu-top-nav">
    <li id="menu-item-1596"><a href="http://localhost:8888/what-we-do/">What we do</a>
        <ul class="sub-menu">
            <p>Explore what we do and the people behind it</p>
            <li id="menu-item-1600"><a href="/what-we-do/about/">About IFSW</a></li>
            <li id="menu-item-1604"><a href="/what-we-do/partners/">Partners</a></li>
            <li id="menu-item-1601"><a href="/what-we-do/contact/">Contact</a></li>
        </ul>
    </li>
</ul>
</nav>

Answer 1

Switch your hover event from the a anchor element to the li element, like so:

nav ul#menu-top-nav li:hover a { color: #fff; background: #111;  }