content：父元素
content-item: 子元素

主轴上子元素平均分布

.content {
	display: flex;
	flex-wrap: wrap;
	justify-content: space-between;
	.service-item {
		display: flex;
		flex-direction: column;
		justify-content: center;
		align-items: center;
		width: 80px;
		height: 80px;
	  }
}

效果：

给父元素添加伪元素

.content:after {
	content: "";
	flex: auto;
}
.content {
	display: flex;
	flex-wrap: wrap;
	justify-content: space-between;
	.service-item {
		display: flex;
		flex-direction: column;
		justify-content: center;
		align-items: center;
		width: 80px;
		height: 80px;
	}
}

效果：