Absolute position top in relative box different between browsers

Question

I have a sub navigation which is placed in two different places on different browsers, and I'm unsure why. I do realise that using margin-top instead of top does fix this but the problem with that is that I have a jQuery slide animation when the sub navigation comes out and it doesn't look nice when I use margin-top since it comes out further up than it is. Here is a picture of the difference:

http://jsfiddle.net/eAqev/ <-- JS Fiddle

HTML:

    <div id="navigation">
        <ul>
            <li><h1>01. About</h1><h2>Learn about us</h2></li>
            <li class="button"><h1>02. Products</h1><h2>View our selection of products</h2>
                <ul class="scrollDown">
                    <li><p>Kitchen Worktops</p></li>
                    <li><p>Upstands/Splashbacks</p></li>
                    <li><p>Gables/ Panels</p></li>
                    <li><p>Glass</p></li>
                    <li><p>High Gloss</p></li>
                    <li><p>Bathroom Tops</p></li>
                    <li><p>Sinks/ Taps</p></li>
                </ul>
            </li>
            <li><h1>03. Contact</h1><h2>Contact us!</h2></li>
            <li><h1>04. Gallery</h1><h2>View photos of us</h2></li>
        </ul>
    </div>

CSS:

#navigation ul {
    display: inline;
    position: relative;
}

#navigation ul li {
    float: left;
    width: 200px;
    height: 35px;
    margin: 10px;
    list-style: none;
    border-bottom: 3px solid #ccc;
}

#navigation ul li:hover {
    border-bottom: 6px solid #eee;
    cursor: pointer;
}

#navigation ul ul {
    position: absolute;
    z-index: 1500;
    margin: 0;
    padding: 0;
    list-style:none;
    background: #fff;
    width: 200px;
    top: 60px;
    opacity:0.95;
    filter:alpha(opacity=95);
    -moz-opacity:0.95;
}

Answer 1

You made everything clear Just add the below codes.It will fix your problem

    #navigation ul ul {
    position: absolute;
    z-index: 1500;
    margin: 0 !important;
    padding: 0 !important;
    list-style:none;
    background: #fff;
    width: 200px;
    top: 60px;
    opacity:0.95;
    filter:alpha(opacity=95);
    -moz-opacity:0.95;
     }  


      #navigation ul {
      display: inline;
      z-index:10;
       position: relative;
        }

Most probably IE7 will have a buggy environment. This will work fine with IE8+.