[css] CSS text-align not working

I have this css code here

.navigation{
    width:100%;
    background-color:#7a7a7a;
    font-size:18px;
}

.navigation ul {
    list-style-type: none;
    margin: 0;
}

.navigation li {
    float: left;
}


.navigation ul a {
    color: #ffffff;
    display: block;
    padding: 0 65px 0 0;
    text-decoration: none;
}

What I am trying to do is center my class navigation. I tried using text-align:center; and vertical-align:middle; but neither of them worked.

and here is the HTML Code

<div class="navigation">
<ul>
<li><a href="http://surfthecurve.ca/">home</a></li>
<li><a href="http://surfthecurve.ca/?page_id=7">about</a></li>
<li><a href="http://surfthecurve.ca/?page_id=9">tutors</a></li>
<li><a href="http://surfthecurve.ca/?page_id=11">students</a></li>
<li><a href="http://surfthecurve.ca/?page_id=13">contact us</a></li>
</ul>
</div><!--navigation-->

When I say its not working, I mean the text is aligned to the left.

I try to avoid floating elements unless the design really needs it. Because you have floated the <li> they are out of normal flow.

If you add .navigation { text-align:center; } and change .navigation li { float: left; } to .navigation li { display: inline-block; } then entire navigation will be centred.

One caveat to this approach is that display: inline-block; is not supported in IE6 and needs a workaround to make it work in IE7.

You have to make the UL inside the div behave like a block. Try adding

.navigation ul {
     display: inline-block;
}