纯CSS实现的背景渐变效果代码！

body {
background-color:  firebrick;
-webkit-animation: color 5s ease-in  0s infinite;
-moz-animation: color 5s linear  0s infinite;
animation: color 5s linear  0s infinite;
}

/* by www.honglonglong.com */

@-webkit-keyframes color {
0% { background-color: cyan; }
30% { background-color: green; }
50% { background-color: yellow }
70% { background-color: orchid; }
100% { background-color: royalBlue; }
}
@-moz-keyframes color {
0% { background-color: cyan; }
30% { background-color: green; }
50% { background-color: yellow; }
70% { background-color: orchid; }
100% { background-color: royalBlue; }
}
@keyframes color {
0% { background-color: cyan; }
30% { background-color: green; }
50% { background-color: yellow; }
70% { background-color: orchid; }
100% { background-color: royalBlue; }
}