<div class="container">
  <div class="item">1</div>
  <div class="item">2</div>
  <div class="item">3</div>
</div>

.container {
  display: flex;
  gap: 10px;
  border: 2px solid #ccc;
  padding: 10px;
}

.item {
  background-color: #ffcccb;
  text-align: center;
  padding: 20px;
  color: #333;
  border: 1px solid #333;
  flex: 1; /* Default flex value */
}

.item:nth-child(2) {
  flex: 2; /* This item will grow twice as much as others */
}