背景不断重复，即使没有重复

button {
  background:#fff;
  padding:0px;
  border:1px solid #ddd;
  cursor:pointer;
  outline:none;
  width:140px;
  height:47px;
  color:#444;
}
.fave {
  width: 70px;
  height: 50px;
  background: url(https://cssanimation.rocks/assets/images/posts/steps/twitter_fave.png) no-repeat;
  background-position: 0 0;
  padding:15px 50px;
}
.fave:hover {
  background-position: -3519px 0;
  transition: background 1s steps(55);
}button {
  background:#fff;
  paddi