小程序flex排列方式
排列方式：display: flex;flex-direction: row;（行排）flex-direction:column；（竖排）对齐方式：justify-content: space-around;（距离两边空间相等间隔）justify-content: space-between;（齐平两边中间间隔）填充之后会距离两边有边距 padding: 20rpx;justify-content: flex-start;（齐平左边）align-items: center;（居中对齐）..
