HTML&CSS - border-box

by Code_Garage

HTML

<div style="background-color: #3498db; width: 200px; height: 100px; padding-top: 10px;">
  <div style="background-color: #f39c12; width: 100%; padding: 10px; border: 10px solid #e67e22;">
    width: 100%
  </div>
</div>

CSS

* {
  box-sizing: border-box;
}