.dev-state {
  background-size: 100% 100%;
  display: inline-block;
  width: 40px;
  height: 40px;
}
.dev-state.dev-s {
  background-image: url('../images/dev/dev-s.png');
}
.dev-state.dev-w {
  background-image: url('../images/dev/dev-w.png');
}
.dev-state.dev-e {
  background-image: url('../images/dev/dev-e.png');
}