#stage {
  background-image: url("img/main/back-main.jpg");
	background-repeat: no-repeat;
	background-size: contain;
	left: 0; top: 0; right: 0; bottom: 0;
}

#main-btn-spring {position: absolute; width: 27.0%; height: 48.0%; left: 50.0%; top:  2.0%; background-image: url("img/main/btn-spring.png"); background-repeat: no-repeat; background-size: contain;}
#main-btn-summer {position: absolute; width: 27.0%; height: 48.0%; left: 50.0%; top: 50.0%; background-image: url("img/main/btn-summer.png"); background-repeat: no-repeat; background-size: contain;}
#main-btn-autumn {position: absolute; width: 27.0%; height: 48.0%; left: 23.0%; top: 50.0%; background-image: url("img/main/btn-autumn.png"); background-repeat: no-repeat; background-size: contain;}
#main-btn-winter {position: absolute; width: 27.0%; height: 48.0%; left: 23.0%; top:  2.0%; background-image: url("img/main/btn-winter.png"); background-repeat: no-repeat; background-size: contain;}