.grid {
  display: grid;
  grid-template-columns: 200px 200px;
  grid-template-rows: 200px 200px;
  grid-template-areas: 'a b'
                       'c d';
  /*对齐单元格的起始位置 */
  justify-items:center;
  align-items: center;
}
.item {
  width: 100px;
  height: 100px;
  background: #80cac8;
}