CSS3文字逐行向上滚动轮换动画特效

代码片段：

<style type="text/css">
.menu-list{list-style:none; width:300px; margin: 100px auto;}
.menu-list li{display:block;}
.list{list-style: none; margin-left: -50px;  width:300px; height:60px; overflow:hidden; }
.list li{width: 300px;height: 60px; position: relative; animation: myfirst 4s infinite ;line-height: 60px;text-align: center; font-size: 30px;color:#fff;}
@keyframes myfirst
{
0%    {background-color:#4ec7f3;  top:0px;}
25%   {background-color:#4ec7f3;  top:0px;}
50%  {background:#42c58a; top:-60px;}
75%  {background:#a0a0a0; top:-120px;}
100%  {background:#dc143c; top:-180px;}

}           
.font30{
font-size: 30px;
color: #7d7d7d;
}
</style>