CSS: Text wont center?

Question

Can anybody see where I am going wrong with this? I am trying to center the text in a button for the navigation using CSS.

#nav {
margin:20px 0 0 0;

}

#nav ul {
margin:0;
}

#nav li:first-child {
width:80px;
height:30px;
display:inline-block;
background-color:#8f00ae;
text-align:center;
 }   
#nav ul li a {  
}

And here is my html.

    <!-- Navigation Section -->
        <div class="cl" id="nav">
            <div class="menu-top_nav-container">
<ul id="menu-top_nav" class="menu">
<li id="menu-item-13" class="menu-item menu-item-type-taxonomy menu-item-object-category menu-item-13">
<a href="http://localhost:8888/?cat=3">Features</a>
</li>
<li id="menu-item-18" class="menu-item menu-item-type-taxonomy menu-item-object-category   menu-item-18">
<a href="http://localhost:8888/?cat=4">Noize Live</a>
</li>
</ul>
</div>
</div>

Answer 1

Probably because the navigation is being floated.. therefor it does not respond to text-align:center; Its difficult without access to the whole html and css sheets but try the following:

#nav li:first-child a 
{
padding: 0 20px;
}