[CSS] The heigh automatically changes by the width

gistfile1.md

Create box width and Height ratio Thank Nghiep, go to link

<!--- code HTML -->
<div class="constant-width-to-height-ratio"></div>

# Code CSS
.constant-width-to-height-ratio {
  background: #333;
  width: 150px;
}
.constant-width-to-height-ratio::before {
  content: '';
  padding-top: 60%; // ratio 
  float: left;
}
.constant-width-to-height-ratio::after {
  content: '';
  display: block;
  clear: both;
}