JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://netdna.bootstrapcdn.com/twitter-bootstrap/2.3.2/css/bootstrap-combined.min.css">
<link rel="stylesheet" href="http://netdna.bootstrapcdn.com/font-awesome/3.2.1/css/font-awesome.min.css">
<a href="/" class="btn btn-large login_facebook"><i class="icon-facebook"> </i> | Sign in with Facebook</a>

CSS

body{
    background-color: green;
}

.login_facebook {
    background: #6e86bd;
    background: -moz-linear-gradient(top, #6e86bd 0%, #6680b9 100%);
    background: -webkit-gradient(linear, 0% 0%, 0% 100%, from(#6e86bd), to(#6680b9));
    border-top: 1px solid #3f5b98;
    border-left: 1px solid #3f5b98;
    border-bottom: 1px solid #3f5b98;
    border-right: 1px solid #3f5b98;
    -moz-border-radius: 6px;
    -webkit-border-radius: 6px;
    border-radius: 6px;
    -moz-box-shadow: inset 0 1px 0 0 #abbbdf;
    -webkit-box-shadow: inset 0 1px 0 0 #abbbdf;
    box-shadow: inset 0 1px 0 0 #abbbdf;
    color: #fff;
    font-weight: bold;
    text-align: center;
    text-shadow: 0 -1px 1px #344d80;
    margin: 0 0 10px 0;
    vertical-align: top;
    position: relative;
}
.login_facebook .icon-facebook {
    font-size: 37px;
    vertical-align: bottom;
    position: relative;
    bottom: 0;
    line-height: 0px;
}