<div class="container clearfix">
  <div class="item float">1</div>
  <div class="item float">2</div>
  <div class="item float">3</div>
</div>
.container {
  border: 4px solid;
}

.container .item {
  width: 100px;
  height: 100px;
  background-color: royalblue;
  border-radius: 10px;
  font-size: 40px;
  margin: 10px;
}

.float {
  float: left;
}

.clearfix::after {
  content: '';
  display: block;
  clear: both;
}

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.