/* 背景を黒く、テキストカラーを白に変更 */
.favorite-button{
  position: relative;
  display: inline-block;
  font-weight: bold;
  padding: 0.25em 0.5em;
  text-decoration: none;
  color: #00BCD4;
  background: #ECECEC;
  transition: .4s;
}

.favorite-button.fav-items{
    background-color: #fc6b03;
    color: #fff;
}