Fake Flexbox

fauxbox.html

<section>
  <nav></nav>
  <article></article>
</section>

<style>
  nav{
    top: 0;
    bottom: 0;
    left: 0;
    position: absolute;
    width: 50px;
  }
  
  article{
    padding-left: 50px;
  }
    
</style>