CSS3 animated button

Semantic HTML. Uses pseudo-elements but only "fully animated" in Firefox 4 for now.

by necolas

HTML

<div class="mod">
    <a href="#" class="btn">Press this!</a>
</div>

<p class="notes">Animated button using CSS3 and pseudo-elements by <a href="http://nicolasgallagher.com">Nicolas Gallagher</a>. Best viewed in Firefox 4.</p>

CSS

body {    
    padding: 2em 5em;
    font-family: Arial, sans-serif;
    font-size: 250%;
    background: #eee;
}

a {
    text-decoration: none;
    color: #fff;
    border: none;
}

div.mod {    
    margin: 0 0 30px 0;
    padding: 80px;
    text-align: center;
    background: #fff;
    -webkit-border-radius: 10px;
    -moz-border-radius: 10px;
    border-radius: 10px;
    -webkit-box-shadow: 0 0 3px rgba(0,0,0,.1);
    -moz-box-shadow: 0 0 3px rgba(0,0,0,.1);
    box-shadow: 0 0 3px rgba(0,0,0,.1);
}

p.notes {    
    margin: 0 0 10px 0;
    font-size: 13px;
    line-height: 1.4;
    color: #999;
    text-align: center;
}

p.notes a {
    color:#666;
}
 
/* button styles */
 
.btn {
    position: relative;
    z-index: 1;
    display: inline-block;
    padding: 10px 20px 18px;
    text-shadow: 0 -1px 1px rgba(19,65,88,.8);
    background: #1a74a1;
    -webkit-border-radius: 8px;
       -moz-border-radius: 8px;
            border-radius: 8px;
    -webkit-box-shadow: 0 10px 20px rgba(0,0,0,.35), inset 0 -1px 1px rgba(255,255,255,.15);
       -moz-box-shadow: 0 10px 20px rgba(0,0,0,.35), inset 0 -1px 1px rgba(255,255,255,.15);
            box-shadow: 0 10px 20px rgba(0,0,0,.35), inset 0 -1px 1px rgba(255,255,255,.15);
    -webkit-transition-property: -webkit-box-shadow; /* drop padding as pseudo-element trans not supported */
       -moz-transition-property: padding, -moz-box-shadow;       
         -o-transition-property: box-shadow; /* drop padding as pseudo-element trans not supported */
            transition-property: padding, box-shadow;
    -webkit-transition-duration: .2s;
       -moz-transition-duration: .2s;
         -o-transition-duration: .2s;
            transition-duration: .2s;
    -webkit-transition-timing-function: ease-in-out;
       -moz-transition-timing-function: ease-in-out;
         -o-transition-timing-function: ease-in-out;
            transition-timing-function: ease-in-out;
}

.btn:active {
    padding: 14px 20px 14px;  
   ...