.link-home {
  width: 180px;
  height: 30px;
  background-image: url('buttons/home.png');
  background-size: contain;
  background-repeat: no-repeat;
}
.link-home:hover {
  background-image: url('buttons/home2.png');
}

.link-sw {
  width: 180px;
  height: 30px;
  background-image: url('buttons/sw.png');
  background-size: contain;
  background-repeat: no-repeat;
}
.link-sw:hover {
  background-image: url('buttons/sw2.png');
}