.maindesign {
margin:1em auto;
}


.maindesign .pic-flex{
	display: flex;
	flex-wrap: wrap;
	justify-content: space-between;
}
.maindesign .pic-flex li{
	width: calc(49% - 2px);
	border: 1px solid #ccc;
	display: flex;
	flex-wrap: wrap;
	align-content: space-between;
	margin-top: 20px;
}
.maindesign .pic-flex li:nth-child(-n + 2){
	margin-top: 0;
}
.maindesign .pic-flex li div{
	width: 100%;
}
.maindesign .one-image{
	border: 1px solid #ccc;
}

.maindesign .one-image li{
	margin: 20px auto;
	width: 606px;
}