title: Div Square, width size based on 100% height
body: <p>I'm trying to make a responsive square with the width size based on the (100%) height of the element. I believe it's impossible using only CSS.</p>
  
  <p>The square width should be equal to the height (100% of the large container. The large container is more than 100% of the screen). The ratio has to be width=height to keep the square.</p>