Center div horizontally and vertically inside another div

Center div horizontally and vertically inside another div

I have a question regarding centering an element horizontally and
vertically inside of another div.
I am working on a website for a client, and here is the page that is
giving me trouble:
http://staging.slackrmedia.com/halfpast/brand_collection_bremont.html
So when you hover over an image, you see a link that says "View
Collection". I'm styling this using CSS3 transitions and opacity, but I'm
having one issue: I need this "View Collection" link to center
horizontally and vertically inside of the div in which it sits.
Here is a link to the jsFiddle with my code: http://jsfiddle.net/T2n5b/4/
HTML
<h2>Bremont Collections</h2>
<div class="row text-center uppercase">
<div class="col-1-3">
<img
src="http://staging.slackrmedia.com/halfpast/images/watches/alt1-p.png"
alt="ALT1-P Pilot" /> <a href="" class="btn small">View
Collection</a>
<a href="">ALT1-P Pilot</a>
</div><!-- .col-1-3 -->
<div class="col-1-3">
<img
src="http://staging.slackrmedia.com/halfpast/images/watches/solo-37.png"
alt="Supermarine" /> <a href="" class="btn small">View
Collection</a>
<a href="">Solo-37</a>
</div><!-- .col-1-3 -->
<div class="col-1-3">
<img
src="http://staging.slackrmedia.com/halfpast/images/watches/bc-f1.png"
alt="BC-F1" /> <a href="" class="btn small">View Collection</a>
<a href="">BC-F1</a>
</div><!-- .col-1-3 -->
</div><!-- .row -->
CSS
/* Buttons
============================= */
.btn {
background: #c60202;
border-bottom: 1 px solid rgba(0, 0, 0, 0.1);
border: 0;
color: #fff;
cursor: pointer;
display: inline-block;
font-size: 1em;
height: 45px;
line-height: 2.9;
margin: 0px;
padding: 0 40px;
position: relative;
text-align: center;
text-decoration: none;
vertical-align: bottom;
width: auto;
text-rendering: optimizeLegibility;
-webkit-font-smoothing: antialiased;
font-smoothing: antialiased;
-webkit-touch-callout: none;
-webkit-user-select: none;
-khtml-user-select: none;
-moz-user-select: none;
-ms-user-select: none;
user-select: none;
-webkit-box-sizing: border-box;
-moz-box-sizing: border-box;
box-sizing: border-box;
-webkit-transition: all .2s ease;
-moz-transition: all .2s ease;
-ms-transition: all .2s ease;
-o-transition: all .2s ease;
transition: all .2s ease;
}
.btn:hover {
background: #d31d1c;
background-image: -webkit-gradient(linear, 0 0, 0 100%, from(rgba(0,
0, 0, 0.05)), to(rgba(0, 0, 0, 0.05)));
background-image: -moz-linear-gradient(top, rgba(0, 0, 0, 0.05),
rgba(0, 0, 0, 0.05));
background-image: -webkit-linear-gradient(top, rgba(0, 0, 0, 0.05),
rgba(0, 0, 0, 0.05));
background-image: -o-linear-gradient(top, rgba(0, 0, 0, 0.05), rgba(0,
0, 0, 0.05));
background-image: linear-gradient(to bottom, rgba(0, 0, 0, 0.05),
rgba(0, 0, 0, 0.05));
background-repeat: repeat-x;
}
.btn.small {
font-size: 0.9em;
line-height: 2.4;
height: 35px;
padding: 0 15px;
}
a.btn {
color: #fff;
text-decoration: none;
}
/*
* Type Styles
*/
.text-center {
text-align: center;
}
.uppercase {
text-transform: uppercase;
}
/* Grid
============================= */
*, *:after, *:before {
box-sizing: border-box;
-moz-box-sizing: border-box;
-webkit-box-sizing: border-box;
}
.row {
margin-left: -20px;
}
.row:after {
clear: both;
content:"";
display: table;
}
/*
* Grid Gutters
*/
[class*='col-'] {
float: left;
padding-left: 20px;
}
.row-pad {
padding: 20px 0 20px 20px;
}
.row-pad[class*='col-']:last-of-type {
padding-right: 20px;
}
/*
* Grid Columns
*/
.col-1-3 {
width: 300px;
}
/*
* Button Hover
*/
.row .col-1-3 img {
display: block;
width: 163px;
height: 276px;
margin: 0 auto 10px;
}
.row .col-1-3 a.btn.small {
font-size: 0.75em;
margin: -165px 0 0 -80px;
opacity: 0;
position: absolute;
}
.row .col-1-3 a.btn.small:hover {
opacity: 1;
}
Any solution with HTML, CSS, or jQuery is perfectly fine. I think there
might just be a small issue with my HTML and CSS that I'm currently using,
but I just can't figure it out.