.tweetthis a {
  font-family: sans-serif;
  background: #369;
  color: #fff;
  border-radius: 5px;
  display: inline-block;
  padding: 5px 10px;
  text-decoration: none;
  text-shadow: 0px 1px 2px #000;
  transition: 0.5s;
  line-height: 20px;
  font-size: 20px;
  box-shadow: 0px 2px 2px #666;
}
.tweetthis a:hover {
  background: #69c;
}