*{margin: 0;padding: 0;}

.big_box{
	width: 100%;
	overflow: hidden;
	box-sizing: border-box;
	padding: 100px 0;
}

.box{
	width: 1200px;
	margin: 0 auto;
}

@media(max-width:980px){
	.big_box{
		width: 100%;
		padding: 30px 0;
	}
	
	.box{
		width: 100%;
		height: 100%;
		margin: 0;
	}
}