Center DIV content Fluid Vertical and Horizontal - html

Question

This is the example I have:
Line height does not apply to fluid divs. The code I have is currently based on line-height but the the sizes of the boxes change. So how can I have a link (content) always in the exact middle?
I want to make sure that the content inside this DIV is always going to be equally centered from the top and the sides. Vertical and Horizontal centered.
Current code: (note style tag is blank as this is dynamic filled)
<style type="text/css">
.box{
width:468px; /* php changes this sometimes */
height:60px; /* php changes this sometimes */
background:#eee;
text-align:
center;
border:
1px solid rgb(177, 172, 171);
line-height: 61px;
}
</style>
<div style="" class="box" id="">
<a style="color:#333;font-weight:bold" href="claimPrize();">Winner!</a>
</div>

Answer 1

Ran into a similar situation not too long ago, did a search and found an article about absolute centering from css-tricks, here is the article and an accompanying fiddle to test it out.
CSS
/* This parent can be any width and height */
.block {
text-align: center;
}
/* The ghost, nudged to maintain perfect centering */
.block:before {
content: '';
display: inline-block;
height: 100%;
vertical-align: middle;
margin-right: -0.25em; /* Adjusts for spacing */
}
/* The element to be centered, can
also be of any width and height */
.centered {
display: inline-block;
vertical-align: middle;
width: 300px;
}
HTML
<div class="block" style="height: 300px;">
<div class="centered">
<h1>Some text</h1>
<p>But he stole up to us again, and suddenly clapping his hand on my shoulder, said—"Did ye see anything looking like men going towards that ship a while ago?"</p>
</div>
</div>
<div class="block" style="height: 200px;">
<div class="centered">
<h1>Some text</h1>
<p>But he stole up to us again, and suddenly clapping his hand on my shoulder, said—"Did ye see anything looking like men going towards that ship a while ago?"</p>
</div>
</div>
<div class="block" style="height: 600px;">
<div class="centered">
<h1>Some text</h1>
<p>But he stole up to us again, and suddenly clapping his hand on my shoulder, said—"Did ye see anything looking like men going towards that ship a while ago?"</p>
</div>
</div>
Demo
http://jsfiddle.net/andresilich/YqKMH/