網格區域

* {
  box-sizing: border-box;
}

.wrapper {
  border: 2px solid #f76707;
  border-radius: 5px;
  background-color: #fff4e6;
}

.wrapper > div {
  border: 2px solid #ffa94d;
  border-radius: 5px;
  background-color: #ffd8a8;
  padding: 1em;
  color: #d9480f;
}

.wrapper {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: 100px 100px;
  grid-template-areas:
    "a a b"
    "a a b";
}
.item1 {
  grid-area: a;
}
.item2 {
  grid-area: b;
}

<div class="wrapper">
  <div class="item1">Item</div>
  <div class="item2">Item</div>
</div>