CSS源码:

*{
    margin:0;
    padding:0;
}
html{
    background-color: #eaf0f2;
}
.container{
    text-align: center;
    font: bold 14px sans-serif;
}
.dropdown{
    text-align: center;
    width: 200px;
    margin: 50px auto 160px;
    position: relative;
    color: gray;
}
.dropdown a{
    display: block;
    box-sizing: border-box;
    text-decoration: none;
    color: #FFF;
    text-align: center;
    background-color: #6BB9E1;
    font-size: 13px;
    width: 120px;
    padding: 9px 0;
    border-radius: 2px;
    margin: 4px auto 0;
    opacity: 0.8;
    -webkit-transition: 0.2s ease;
    transition: 0.2s ease;
}
.dropdown span {
    background-color: #EC7164;
    display: block;
    box-sizing: border-box;
    color: #FFF;
    text-align: left;
    font-size: 16px;
    width: 200px;
    padding: 11px 15px;
    line-height: 1;
    border-radius: 3px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2);
}
.dropdown span:after{
    content: '';
    position: absolute;
    right: 20px;
    top: 17px;
    width: 0;
    height: 0;
    border-style: solid;
    border-width: 5px 5px 0 5px;
    border-color: #fff transparent transparent transparent;
    -webkit-transition: 0.2s ease-in;
    transition: 0.2s ease-in;
}
.dropdown ul li a.active{
    background-color: #687AD7;
    opacity: 0.8 !important;
}
.dropdown ul li a:hover {
    opacity: 1;
}
.dropdown ul{
    position: absolute;
    z-index: 200;
    left: 50%;
    margin: 10px 0 0 -250px;
    list-style: none;
    padding: 0;
    overflow: hidden;
    width: 500px;
    height: 0;
    -webkit-transition: 0.4s ease;
    transition: 0.4s ease;
}
.dropdown ul li{
    display: inline-block;
}
.dropdown:hover ul {
    height: 180px;
}
/*------------------------------------
Demo footer. Ignore and remove
-------------------------------------*/
footer {
    font: normal 16px Arial, Helvetica, sans-serif;
    padding: 15px 35px;
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background-color: #1B1F22;
    box-shadow: 0 -1px 1px rgba(0, 0, 0, 0.2);
    z-index: 1;
}
footer a.tz{
    font-weight: normal;
    font-size: 16px !important;
    text-decoration: none !important;
    display: block;
    margin-right: 300px;
    text-overflow: ellipsis;
    white-space: nowrap;
    color: #CCC !important;
    position: relative;
    padding-left: 140px;
}
footer a.tz:before{
    font-weight: bold;
    color: #FFF;
    content: 'tutorial';
    position: absolute;
    text-align: right;
    width: 100px;
    left: -20px;
}
footer a.tz:after{
    content: 'zine';
    position: absolute;
    font-weight: bold;
    color: #DA431C;
    left: 80px;
}
footer .close{
    position: absolute;
    cursor: pointer;
    width: 8px;
    height: 8px;
    top: 10px;
    right: 12px;
    color: #FFF;
    font-weight: bold;
    font-size: 12px;
    line-height: 12px;
}
footer #tzine-actions{
    position: absolute;
    top: 15px;
    right: 30px;
    width: 340px;
    text-align: right;
}
footer #tzine-actions iframe{
    display: inline-block;
    height: 21px;
    width: 95px;
}
@media (max-width: 1024px) {
    #bsaHolder, footer{ display:none;}
}
Index:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>12 Fun Sharing Button Effects</title>
<link rel="stylesheet" href="./assets/css/demo.css">
<style>
.image-effect-fall-back{
    width: 500px;
    height: 300px;
    position: relative;
    margin: 0 auto;
    -webkit-perspective: 800px;
    perspective: 800px;
}
.image-effect-fall-back .image-layer{
    position: absolute;
    top:0;
    left: 0;
    height: 300px;
    -webkit-transition: 0.6s;
    transition: 0.6s;
    z-index: 1;
}
.image-effect-fall-back:hover .image-layer{
    -webkit-transform: rotateX(70deg);
    transform: rotateX(70deg);
    overflow: visible;
}
.image-effect-fall-back .image-layer img{
    height: 100%;
}
.image-effect-fall-back .image-layer:before{
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    box-shadow: 0 0 100px 50px rgba(0, 0, 0, 0.5);
    opacity: 0;
    -webkit-transition: all 0.5s;
    transition: all 0.5s;
    -webkit-transform: rotateX(114deg) translateZ(-26px) translateY(110px) scale(0.75);
    transform: rotateX(114deg) translateZ(-26px) translateY(110px) scale(0.75);
    -webkit-transform-origin: bottom;
    -ms-transform-origin: bottom;
    transform-origin: bottom;
}
.image-effect-fall-back:hover .image-layer:before {
    opacity: 0.3;
}
.image-effect-fall-back .share-layer{
    position: absolute;
    bottom: 100px;
    left: 0;
    width: 100%;
    height: 100px;
    opacity: 0;
    z-index: 10;
    -webkit-transition: 0.6s;
    transition: 0.6s;
    -webkit-transform: rotateX(70deg);
    transform: rotateX(70deg);
}
.image-effect-fall-back:hover .share-layer {
    opacity: 1;
    -webkit-transform: rotateX(0deg) translateY(-70px);
    transform: rotateX(0deg) translateY(-70px);
}
.share-button{
    display: inline-block;
    text-decoration: none;
    color: #ffffff;
    padding: 12px;
    width: 80px;
    border-radius: 2px;
    margin:25px 10px;
}
.share-via-facebook{
    background-color:#3b5998;
}
.share-via-twitter{
    background-color:#00aced;
}
.share-via-google{
    background-color:#d34836;
}
</style>
</head>
<body>
<div class="container">
<div class="dropdown">
<span>Choose a Demo</span>
<ul class="button-effects-list">
<li><a href="index.html" class="active">Fall Back</a></li>
<li><a href="paper-flip.html">Paper Flip</a></li>
<li><a href="rumble.html">Rumble</a></li>
<li><a href="3d-doors.html">Doors 3D</a></li>
<li><a href="circles.html">Circles</a></li>
<li><a href="rotation.html">Rotation</a></li>
<li><a href="simple.html">Simple</a></li>
<li><a href="doors.html">Doors</a></li>
<li><a href="zoom.html">Zoom</a></li>
<li><a href="border.html">Border</a></li>
<li><a href="future.html">Future</a></li>
<li><a href="pop-ups.html">Pop Ups</a></li>
</ul>
</div>
<div class="image-effect-fall-back">
<div class="share-layer">
<a href="#" class="share-button share-via-facebook">
<i class="fa fa-facebook"></i>
Facebook
</a>
<a href="#" class="share-button share-via-twitter">
<i class="fa fa-twitter"></i>
Twitter
</a>
<a href="#" class="share-button share-via-google">
<i class="fa fa-google"></i>
Google +
</a>
</div>
<div class="image-layer">
<img src="assets/pictures/tree.jpg" width="500" alt="California surf">
</div>
</div>
</div>
<footer>
<a class="tz" href="http://tutorialzine.com/2014/11/12-fun-sharing-button-effects/">12 Fun Sharing Button Effects</a>
<div id="tzine-actions"></div>
<span class="close">✕</span>
</footer>
<!-- Demo ads. Please ignore and remove. -->
<script src="http://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="http://cdn.tutorialzine.com/misc/enhance/v2.js" async></script>
</body>
</html>