.container {
  width: 300px;
  height: 300px;
  display: grid;
  grid-gap: 15px;
  grid-template-areas:
  "a b"
  "c c"
  "c c";
}

.item {
  height: 100%;
  width: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
}

.item h1 {
  margin: 0;
  color: white;
}

.item.a {
  background-color: #ff914d;
  grid-area: a;
}

.item.b {
  background-color: #7ed957;
  grid-area: b;
}

.item.c {
  background-color: #38b6ff;
  grid-area: c;
}