<div class="flex">
  <div class="ele1"></div>
  <div class="ele2"></div>
</div>
.flex {
  display: flex;
  width: 300px;
  height: 300px;
  border: 1px solid black;
}

.ele1,
.ele2 {
  border: 1px solid black;
  width: 100px;
  margin: 5px;
}

External CSS

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External JavaScript

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