/* CSS动画代码 */
.animated-element {
  animation-name: fadeIn;
  animation-duration: 1s;
  animation-timing-function: ease;
  animation-delay: 0s;
  animation-iteration-count: 1;
  animation-direction: normal;
  animation-fill-mode: both;
  
  /* 简写形式 */
  animation: fadeIn 1s ease 0s 1 normal both;
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}