title: How to write css fallbacks for vh vw
body: <p>Can anyone explain how fallbacks work in CSS? I am trying to set it up for vh and vw and clearly I am not getting it...</p>
  
  <p>Here is my attempted solution, which does not work. The height property is taken every time.</p>
  
  <p>CSS:</p>
  
  <pre><code>-webkit-height: 5.2vh;
  -moz-height: 5.2vh;
  -ms-height: 5.2vh;
  -o-height: 5.2vh;
  height: 41px; /* The Fallback */
  </code></pre>