html,
body {
	width: 100vw;
	height: 100vh;
	overflow: hidden;
	background-position: center;
	background-size: cover;
	background-repeat: no-repeat;
}

/* 首页 */
.bg_1 {
	width: 100%;
	height: 100%;
	background-color: #f4f4f4;
	background-position: center;
	background-size: cover;
	background-repeat: no-repeat;
	position: relative;
	/* display: none; */
	/* opacity: 0; */
}

.top_img {
	text-align: center;
}

.top_img img{
	width: 10rem;
	height: 8.533333rem;
}

.btn_group{
	display: flex;
	flex-direction: column;
	margin-top: 0.266667rem;
}

.btn_item{
	display: flex;
	justify-content: center;
	margin-bottom: 0.266667rem;
}

.btn_item img{
	width: 8.466667rem;
	height: 1.733333rem;
}

@media screen and (min-height:750px) {
	.btn_group{
		margin-top: 4vh;
	}
	.btn_item{
		margin-top: 2vh;
	}
}