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/* 背景精灵图的公共类 */
.jd-sprite:before {
content: '';
background: url(../images/icons/xxx.png) 0 0 no-repeat;
-webkit-background-size: 200px;
background-size: 200px;
}
/* 水平垂直居中公共类 */
.center-xy:before,.center-self-xy {
position: absolute;
left: 50%;
top: 50%;
-webkit-transform:translate(-50%,-50%);
transform:translate(-50%,-50%);
}
/* 水平居中公共类 */
.center-x:before,.center-self-x {
position: absolute;
left: 50%;
-webkit-transform:translateX(-50%);
transform:translateX(-50%);
}
/* 垂直居中公共类 */
.center-y:before,.center-self-y {
position: absolute;
top: 50%;
-webkit-transform:translateY(-50%);
transform:translateY(-50%);
}