#signup{height:880px;width:760px;margin:auto}
#btn_register{width:340px;height:137px}
#btn_register a{width:340px;height:137px;background:url(../img/register/advantages/btn.jpg) no-repeat top;display:block;text-indent:-999px;overflow:hidden}
#btn_register a:hover{background-position:bottom}