<div id="demo">
  <img id="logo" src="https://s3-us-west-2.amazonaws.com/s.cdpn.io/62127/exampleco.svg" alt="ExampleCo" width="200" height="130">
</div>

#logo {
  display: block;
  height: 33.3%;
  width: 100%;
}

/**
 * Below styles for demo only
 */

#logo {
  outline: 1px solid #DBE5EA;
}

html {
  background: #444;
  height: 100%;
}

body {
  max-height: 100%;
  overflow: hidden;
}

#demo {
  background: #fff;
  border: solid #111;
  border-radius: 1em;
  border-width: 2em 1em;
  display: block;
  height: 26em;
  margin: 1em auto;
  padding: 2em;
  width: 16em;
  animation: 2s ease resizeDemo alternate infinite;
}

@keyframes resizeDemo {
  0% {
    border-width: 2em 1em;
    height: 26em;
    width: 16em;
  }
  
  25% {
    border-width: 2em 1em;
    height: 26em;
    width: 16em;
  }
  
  75% {
    border-width: 1em 2em;
    height: 16em;
    width: 26em;
  }
  
  100% {
    border-width: 1em 2em;
    height: 16em;
    width: 26em;
  }
}