//浏览器前缀
background: linear-gradient(red, blue);
background: -webkit-linear-gradient(red, blue);
background: -o-linear-gradient(red, blue);
background: -moz-linear-gradient(red, blue);
to top :颜色从下往上渐变：
background:-webkit-linear-gradient(to top, red, blue);
background:linear-gradient(to top,red,blue);
to bottom :颜色从上往下渐变：
background:-webkit-linear-gradient(to bottom, red, blue);
background:linear-gradient(to bottom,red,blue);
to left :颜色从右往左渐变
background:-webkit-linear-gradient(to left, red, blue);
background:linear-gradient(to left,red,blue);
to right :颜色从左往右渐变：
background:-webkit-linear-gradient(to right, red, blue);
background:linear-gradient(to right,red,blue);
to right :颜色从左往右渐变：
background:-webkit-linear-gradient(to right, red, blue);
background:linear-gradient(to right,red,blue);
to bototm right :颜色从左上角度到右下角渐变：
background:-webkit-linear-gradient(to right, red, blue);
background:linear-gradient(to right,red,blue);
to top left :颜色从右下角度到左上角渐变：
background:-webkit-linear-gradient(to right, red, blue);
background:linear-gradient(to right,red,blue);
