CSS Dropdown无法在Firefox中运行？

Question

我正在尝试创建CSS下拉列表。它在Chrome中运行良好，但链接在Firefox的页面左侧下拉。有任何想法吗？谢谢！

CSS

 .links  ul ul { /* lists within lists... */
  position: absolute; /* place them over the top of everything */
  display: none; /* hide 'em */
  width: 180px;
}

 .links li:hover ul { /* when list items are hovered over, do this to lists contained         within them... */
  display: block; /* show 'em */
}  

HTML

<nav class="links">
    <ul>
        <li><a href="./html/management.html">Management Info</a></li>
        <li><a href="./html/schedule.html">Schedule</a></li>
        <li><a href="./html/lyrics.html">Lyric Checker</a></li>
        <li><a href="">Calendar</a></li>
        <li><a href="">Resources &#x25bc;</a>
            <ul class="links">
                <li><a href="html/how_to_itunes.html">iTunes Tips</a></li>
                <li><a href="html/how_to_simian_format.html">Simian Format</a></li>
                <li><a href="html/how_to_simian_liner.html">Simian Liner</a></li>
                <li><a href="html/how_to_news.html">News at &#58;55</a></li>
            </ul>
        </li>
    </ul>
</nav>