<div class="container">
  <div class="first">Box 1</div>
  <div class="second">Box 2</div>
  <div class="third">Box 3</div>
</div>
.container {
  display: flex;
  border: 1px dotted black;
  font-family: arial;
  font-weight: bold;
}

.first {
  background-color: salmon;
  border: 1px solid black;
  height: 100px;
  width: 320px;
}

.second {
  background-color: skyblue;
  border: 1px solid black;
  height: 160px;
  width: 100px;
}

.third {
  background-color: goldenrod;
  border: 1px solid black;
  height: 80px;
  width: 240px;
}

External CSS

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External JavaScript

This Pen doesn't use any external JavaScript resources.