@keyframes fadein {
0%{
opacity:0;
background-color:red;
}
40% {
background-color:darkblue;
}
70% {
background-color:gold;
}
100% {
opacity:1;
background-color:yellow;
}
}
body {
-webkit-animation:fadein 5s linear 1;
}
#animate_1{
border:1px solid red;
width:300px;
height:300px;
}
#animate_1{
animation: fadein 1000ms linear;
}
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http://www.w3school.com.cn/cssref/pr_animation.asp
原文：http://www.cnblogs.com/qinqiu/p/4476836.html