html, body {
	height:100%;
}
.grid1, .grid2, .grid3, .grid4 {
	display:block;
	width:50%;
	height:45%;
	float:left;
	position:relative;
	background-size:cover;
	background-repeat:no-repeat;
}
.grid1 {
	background-image:url('../intro_img/main/main1.jpg');
	background-position:top center;
}
.grid2 {
	background-image:url('../intro_img/main/main3.jpg');
	background-position:bottom center;
}
.grid3 {
	background-image:url('../intro_img/main/main5.jpg');
	background-position:top center;
}
.grid4 {
	background-image:url('../intro_img/main/main4.jpg');
	background-position:center;
}
.grid_txt {
	position:absolute;
	width:130px;
	height:130px;
	box-sizing:border-box;
	z-index:+100;
}
.grid_txt .txt {
	width:100%;
	height:100%;
	box-sizing:border-box;
	font-family:'NGothicB';
	font-size:14px;
	padding-top:58px;
	color:#fff;
	text-align:center;
	position:absolute;
	top:0px;
	left:0px;
	z-index:+9990;
}
.grid_txt .alpha_bg {
	background-color:#000;
	opacity:0.5;
	width:100%;
	height:100%;
	position:absolute;
	top:0px;
	left:0px;
	z-index:0;
}
.grid1 .grid_txt {
	bottom:0px;
	right:0px;
	border-top:2px solid #fff;
	border-left:2px solid #fff;
}
.grid2 .grid_txt {
	bottom:0px;
	left:0px;
	border-top:2px solid #fff;
	border-right:2px solid #fff;
}
.grid3 .grid_txt {
	top:0px;
	right:0px;
	border-bottom:2px solid #fff;
	border-left:2px solid #fff;
}
.grid4 .grid_txt {
	top:0px;
	left:0px;
	border-bottom:2px solid #fff;
	border-right:2px solid #fff;
}
.scr_big {
	display:none;
	width:100%;
	height:100%;
	position:absolute;
	top:0px;
	left:0px;
	z-index:0;
}
.scr_big .alpha_bg {
	position:absolute;
	top:0px;
	left:0px;
	width:100%;
	height:100%;
	background-color:#000;
	opacity:0.5;
	z-index:0;
}
.grid_btn:hover .grid_txt .alpha_bg {
	opacity:1;
	background-color:#b92145;
}
.grid_btn:hover .scr_big {
	display:block;
}

.for_mobile {
	display:block;
}
.for_pc {
	display:none;
}

@media screen and (min-width:768px) and (max-width:1023px){
	.for_mobile {
		display:none;
	}
	.for_pc {
		display:block;
	}
	.grid_txt {
		position:absolute;
		width:230px;
		height:230px;
		box-sizing:border-box;
	}
	.grid_txt .txt {
		width:100%;
		height:100%;
		box-sizing:border-box;
		font-family:'NGothicB';
		font-size:24px;
		padding-top:103px;
		color:#fff;
		text-align:center;
		position:absolute;
		top:0px;
		left:0px;
		z-index:+9990;
	}
}
@media screen and (min-width:1024px){
	body, html {
		min-height:850px;
	}
	.for_mobile {
		display:none;
	}
	.for_pc {
		display:block;
	}
	.grid_txt {
		position:absolute;
		width:230px;
		height:230px;
		box-sizing:border-box;
	}
	.grid_txt .txt {
		width:100%;
		height:100%;
		box-sizing:border-box;
		font-family:'NGothicB';
		font-size:24px;
		padding-top:103px;
		color:#fff;
		text-align:center;
		position:absolute;
		top:0px;
		left:0px;
		z-index:+9990;
	}
}