1. 定义：

@keyframes animationname {keyframes-selector {css-styles;}}

2. 实例：

 1 /* 动画代码 */
 2 @keyframes example {
 3   from {background-color: red;}
 4   to {background-color: yellow;}
 5 }
 6 
 7 /* 向此元素应用动画效果 */
 8 div {
 9   width: 100px;
10   height: 100px;
11   background-color: red;
12   animation-name: example;
13   animation-duration: 4s;
14 }