IR 효과
.ir_pm {display:block; overflow:hidden; font-size:0; line-height:0; text-indent:-9999px;}
.ir_wa {display:block; overflow:hidden; position:relative; z-index:-1; width:100%; height: 100%;}
.ir_so {overflow: hidden; position:absolute; width:0; height:0; line-height:0; text-indent:-9999px;}