.corner {
    background-color: #a00;
    overflow: hidden;
    position: fixed;z-index:99;
    right: -3em;
    top: 2.5em;
    -moz-transform: rotate(45deg);
    -webkit-transform: rotate(45deg);
    transform: rotate(45deg);
    -moz-box-shadow: 0 0 1em #888;
    -webkit-box-shadow: 0 0 1em #888;
    box-shadow: 0 0 1em #888;
}
.corner a {
     border: 1px solid #faa;
     color: #fff;
     display: block;
     font-size:.8em;
     font-weight:bold;
     padding: 0.5em 4em;
     text-align: center;
     text-decoration: none;
     text-shadow: 1px 1px 1px #000;
}