<div class="container">
  <div class="item"></div>
  <div class="item"></div>
  <div class="item"></div>
  <div class="item"></div>
</div>
.container {
  display: flex;
  height: 500px;
  justify-content: center;
  .item {
    flex: 1;
    height: 150px;
    background: blue;
    margin: 10px;
    
    &:nth-child(1) {
      background: blue;
    }
    &:nth-child(2) {
      background: red;
      flex: 2;
    }
    &:nth-child(3) {
      background: pink;
      flex: 2;
    }
    &:nth-child(4) {
      background: orange;
    }
  }
}

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.