背景颜色渐变动态

#footer_wrapper footer {
position: relative;
width: 100%;
height: 330px;
padding-top: 50px;
background: #0a9c46;
background: linear-gradient(88deg, #f28c00, #0a9c46);
background-size: 400% 400%;
-webkit-animation: footer-bg 15s ease infinite;
-moz-animation: footer-bg 15s ease infinite;
animation: footer-bg 15s ease infinite;
}

@-webkit-keyframes footer-bg {
0%{background-position:0% 51%}
50%{background-position:100% 50%}
100%{background-position:0% 51%}
}