#about_mainHeader {
	position: relative;
	margin-top: 50px;
	width: 100vw;
	overflow: hidden;
}

#about_mainHeader_img {
	width: 40vw;
	height: 700px;
	float: left;
	max-width: 620px;
	background-image: url("../images/about/us.jpg");
	background-position: center;
	background-size: cover;
}

#about_mainHeader_txt {
	width: 60vw;
	float: left;
	height: 700px;
}

@media screen and (max-width: 700px) {	
	#about_mainHeader_img {
		width: 100%;
		height: 100vh;
		float: none;
	}
	
	#about_mainHeader_txt {
		width: 90%;
		float: none;
		margin: auto;
		height: auto;
	}
	
	#about_mainHeader_txt div {
		position: relative;
		top: 0;
		left: 0;
		transform: none;
	}
}