gird布局简单定义样式

    display: -ms-grid;//兼容ie
    -ms-grid-columns: 2.16rem 2.16rem 2.16rem;//兼容ie
    display: grid;//gird布局
    grid-template-columns: 2.16rem 2.16rem 2.16rem;//几列，每列宽度
    grid-row-gap: .18rem;//间隔
    justify-content: space-between;//两端对齐
    justify-items: center;//居中
    align-items: center;//居中