<div class="container"><div class="left-div left-text">Foo</div><div class="right-div right-text">Barrrrrr</div></div>

body
{
  background-color: #fcfcfc;
}
.container
{
  text-align: center;
  padding: 15px;  
}
.left-div
{
  display: inline-block;
  max-width: 300px;
  text-align: left;
  padding: 30px;
  background-color: #ddd;
  border-radius: 3px;
  margin: 15px;
  vertical-align: top;
}
.right-div
{
  display: inline-block;
  max-width: 150px;
  text-align: left;
  padding: 30px;
  background-color: #ddd;
  border-radius: 3px;
  margin: 15px;
}
.left-text, .right-text
{
    color: #333;
}
@media screen and (max-width: 600px) 
{
  .left-div, .right-div
    {
       max-width: 100%;
    }
}

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.