动画

原链接：

http://www.yuangongju.com/animate

https://www.cnblogs.com/chengxs/p/8066819.html

https://www.cnblogs.com/ibingbing/p/6485630.html

https://blog.csdn.net/iteye_5904/article/details/82671585

大小收缩动画样式：

.demo{-webkit-animation: btnAnimate 1.8s linear infinite;
    animation: btnAnimate 1.8s linear infinite;}
    @-webkit-keyframes btnAnimate {
      0% {
        -webkit-transform: scale(0.9);
                transform: scale(0.9);
      }
      50% {
        -webkit-transform: scale(1);
                transform: scale(1);
      }
      100% {
        -webkit-transform: scale(0.9);
                transform: scale(0.9);
      }
    }
    @keyframes btnAnimate {
      0% {
        -webkit-transform: scale(0.9);
                transform: scale(0.9);
      }
      50% {
        -webkit-transform: scale(1);
                transform: scale(1);
      }
      100% {
        -webkit-transform: scale(0.9);
                transform: scale(0.9);
      }
    }