background-color:yellow 颜色
background-image:url(XXX.JPG) 图片路径
background-repeat:repeat 平铺
repeat-x 延X轴平铺
repeat-y 延Y轴平铺
no-repeat 单独一张图片
background-positian:(left center right) (top center bottom)
10px 20px
简写模式
background:yellow url(XXX.JPG) no-repeat 10px 20px