<div class="grid">
  <div class="item">1</div>
  <div class="item">2</div>
  <div class="item">3</div>
  <div class="item">4</div>
  <div class="item">5</div>

  <div class="item">1</div>
  <div class="item">2</div>
  <div class="item">3</div>
  <div class="item">4</div>
  <div class="item">5</div>

  <div class="item">1</div>
  <div class="item">2</div>
  <div class="item">3</div>
  <div class="item">4</div>
  <div class="item">5</div>
</div>

.grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-gap: 0.5rem;
}

.item {
  background: #76C2F1;
  padding: 0.5rem 2rem;
}

.item:nth-child(5n + 4) {
  background: #7cc270;
  grid-column: span 2;
}