You should not use a h1 tag inside a unordered list element (ul). Do this instead:
<div class="menu content">
<h1>JEWELLERY</h1>
<ul id="nav">
<li><a href=""> Home </a></li>
<li><a href=""> Jewellery </a></li>
<li><a href=""> Locations </a></li>
<li><a href=""> Contact Us </a></li>
<li><a href=""> Reviews </a></li>
</ul>
</div>
And with something like the following css
.menu {
text-align: center;
}
#nav{
list-style: none;
padding-left: none;
}
#nav li {
display: inline-block;
}
See here http://jsfiddle.net/r8zW5/
That would line them up horizontally. Is this what you meant?