Center a hyperlink inside li element in navigation bar - css

Question

I want to create a navigation bar where the text is centered, but my CSS code places the hyperlink at the top corner of the li as seen in the image.
CSS:
#navigation {
clear: both;
margin: 0 auto 5px;
margin-top: 0;
height: 6%;
padding: 0 5px;
position: relative;
z-index: 1;
}
#navigation a {
height: 10%;
width: 50px;
color: red;
vertical-align: center;
text-align: center;
text-decoration: bold;
}
li {
border-top: solid;
border-right: solid;
border-left: solid;
border-bottom: none;
padding-left: 1px;
height: 51px;
width: 18%;
background-image: url('../images/tab-selected.png');
background-repeat: repeat-x-y;
border-color: #F0F0F0;
display: inline-block;
padding-left: 1px;
}
HTML:
<nav id="navigation">
<ul>
<li >overview</li>
<li >overview</li>
</ul>
</nav>

Answer 1

There are various ways of vertically center something.
If you KNOW the words of the links and know they will not have a line break, you can add line-height:51px; to the anchor (which is the same height of the LI).
Here's the fiddle: http://jsfiddle.net/vMLpL/
By the way, tips for you:
For the border, you can use border:1px solid #f0f0f0; then just give none to bottom, like border-bottom:none; instead of declaring all sides.
When you want a BG to repeat both X and Y, the background-repeat is repeat only, not repeat-x-y.
For the vertical-align, there is no center. It's top, middle, bottom and baseline. But it work only for inline elements regard to other inline elements besides or for display:table-cell elements (which will work like a td's valign="middle" atribute).

Answer 2

Try this:
Remove the following from your "li" selector:
height: 51px;
Add the following to your "li" selector:
text-align: center;
line-height: 51px;