<!doctype html> <!-- Any copyright is dedicated to the Public Domain. http://creativecommons.org/publicdomain/zero/1.0/ --> <meta charset="utf-8"> <title>CSS Test Reference</title> <link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecoal95@gmail.com"> <style> .container { display: block; background: gray; max-height: 200px; } .panel { background: lightblue; width: 150px; height: 200px; border: 1px solid purple; box-sizing: border-box; } </style> <div class="container"> <div class="panel"> </div> </div>