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                <div class="area-one">
  <h2>Calc is awesome</h2>
  <div class="content">
    <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Praesent sollicitudin tortor elementum elit malesuada, eu viverra felis feugiat. Praesent scelerisque eros sit amet ex fermentum, ut dapibus tortor cursus. Duis egestas elit ac euismod vestibulum. Nullam sed pulvinar dui. Cras congue dictum tortor sed auctor. Aenean nisl sapien, auctor sit amet elementum vitae, tincidunt at velit. Aliquam posuere, ipsum sit amet porttitor porta, turpis augue dapibus dolor, ut accumsan sem sapien ac massa. Nulla mauris felis, varius et elit ultricies, tincidunt dapibus velit. Ut lacus odio, congue non rutrum et, posuere sed justo. Donec eu lorem id dolor sodales faucibus. Nullam hendrerit metus vitae iaculis ultricies. Quisque condimentum, arcu sit amet auctor aliquet, nulla nibh varius erat, non lobortis enim velit sit amet nunc. Cras placerat elit neque, in laoreet lacus posuere nec. Mauris lectus est, elementum vitae hendrerit eget, commodo id ipsum. Mauris vestibulum magna nec lorem volutpat sagittis.</p>


                html, body {
  height: 100%;
  background: #7f8c8d;
body {
  padding: 20px;
  background: white;  
* {
  box-sizing: border-box;

.content {
  padding: 15px;
  height: calc(100% - 50px);
  overflow: auto;
  background: #3498db;
  p {
    margin: 0 0 1em 0;

.area-one {
  width: 40%;
  float: left;
  height: 100%;
  margin-right: 1em;
  > h2 {
    background: #2980b9;
    height: 50px;
    line-height: 50px;
    padding: 0 15px;
    color: white;
    margin: 0;