css渐变色

background: -webkit-linear-gradient(red, blue); /* Safari 5.1 - 6.0 /
background: -o-linear-gradient(red, blue); / Opera 11.1 - 12.0 /
background: -moz-linear-gradient(red, blue); / Firefox 3.6 - 15 /
background: linear-gradient(red, blue); / 标准的语法 */