.container {
  width: 600px;
  height: 300px;
  line-height: 300px;
  background-color: #E5E5E5;
  text-align: center;
}

.item {
  display: inline-block;
  width: 200px;
  height: 30px;
  background-color: #fff;
  margin-bottom: 40px;
  
/* 以下所有代码为配置区域 */
  background-size: 400% 100%;
  background-image: linear-gradient(90deg,#fff 25%,#f2f2f2 37%,#fff 63%);
  animation: waveloading 1.4s ease infinite;
}


@keyframes waveloading {
  0% {
    background-position: 100% 50%;
  }

  100% {
    background-position: 0 50%;
  }
}