Social Icons

Pure CSS

HTML

<link rel="stylesheet" href="//netdna.bootstrapcdn.com/font-awesome/4.0.3/css/font-awesome.css">
<div class="fB icon">
    <div class="shadow"></div><span><i class="fa fa-facebook"></i></span>
</div>
<br />
<div class="tW icon">
    <div class="shadow"></div><span><i class="fa fa-twitter"></i></span>
</div>
<br />
<div class="app icon">
    <div class="shadow"></div><span><i class="fa fa-apple"></i></span>
</div>
<br />
<div class="git icon">
    <div class="shadow"></div><span><i class="fa fa-github-alt"></i></span>
</div>
<br />
<div class="stack icon">
    <div class="shadow"></div><span><i class="fa fa-stack-exchange"></i></span>
</div>
<br />
<div class="google icon">
    <div class="shadow"></div><span><i class="fa fa-google-plus"></i></span>
</div>

CSS

html, body {
    font-family: "century gothic";
    font-size: 10px;
    line-height: 10px;
}

body * {
    box-sizing: border-box;
    -webkit-box-sizing: border-box;
    -moz-box-sizing: border-box;
}

.icon {
    width: 100px;
    height: 100px;
    border-radius: 50%;
    border: 5px solid rgba(255, 255, 255, 0.6);
    text-align: center;
    position: relative;
    cursor: pointer;
}

.fB {
    background: #1361C5;
}

.tW {
    background: rgb(1, 154, 210);
}

.app {
    background: gray;
}

.git {
    background: rgb(65, 131, 196);
}

.stack {
    background: #195398;
}

.google {
    background: #096fc7;
}

.shadow {
    height: 45px;
    width: 100%;
    overflow: hidden;
    position: absolute;
    transform: rotate(-45deg);
    -webkit-transform: rotate(-45deg);
    -moz-transform: rotate(-45deg);
    transition: all 0.6s ease;
    -webkit-transition: all 0.6s ease;
    -moz-transition: all 0.6s ease;
    -webkit-transform-origin: center bottom;
    -moz-transform-origin: center bottom;
    transform-origin: center bottom;
}

.shadow:before {
    content: "";
    width: 90px;
    height: 90px;
    position: absolute;
    display: block;
    border-radius: 50%;
    background: rgba(0, 0, 0, 0.1);
}

.icon:hover .shadow {
    transform: rotate(45deg);
    -webkit-transform: rotate(45deg);
    -moz-transform: rotate(45deg);
}

.icon span {
    font-size: 7em;
    line-height: 90px;
    font-weight: bold;
    color: rgba(255, 255, 255, 1);
    position: relative;
    z-index: 10;
    transition: color 0.6s ease;
    -webkit-transition: color 0.6s ease;
    -moz-transition: color 0.6s ease;
}

.google span {
    font-size: 6.5em;
}

.icon:hover span {
    color: rgba(0, 0, 0, 0.4);
}