<div class="box1">BOX 1</div>
<div class="box2">BOX 2</div>
<div class="box3">BOX 3</div>
.box1 {
  background-color: skyblue;
  width: 100px;
  height: 100px;
}

.box2 {
  background-color: yellow;
  width: 100px;
  height: 100px;
  border: 5px solid black;
  padding: 10px;
  box-sizing: border-box;
}

.box3 {
  background-color: red;
  width: 100px;
  height: 100px;
}

External CSS

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External JavaScript

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