<p>1. overflow: hidden</p>
<div class="parent first">
  <div class="child">1</div>
  <div class="child">2</div>
</div>

<p>2. border</p>
<div class="parent second">
  <div class="child">1</div>
  <div class="child">2</div>
</div>

<p>3. inline-block: parent</p>
<div class="parent third">
  <div class="child">1</div>
  <div class="child">2</div>
</div>

<p>4. inline-block: child</p>
<div class="parent fourth">
  <div class="child">1</div>
  <div class="child">2</div>
</div>

.child {
/*   display: inline-block; */
/*   overflow: hidden; */
/*   border: 1px solid black; */
  width: 100px;
  height: 100px;
  color: #fff;
  text-align: center;
  line-height: 100px;
  font-size: 2rem;
  margin: 20px;
}

.child:first-child {
  background-color: royalblue;
}

.child:last-child {
  background-color: gold;
}

.parent {
  width: 140px;
  background-color: grey;
}

.first {
  overflow: hidden;
}

.second {
  border: 1px solid transparent;
}

.third {
  display: inline-block;
}

.fourth > .child {
  display: inline-block;
}

External CSS

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External JavaScript

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