title: How do I position a div after a div or at the bottom depending the window size? (image example)
body: <p>I want a div to be below its sibling, if the browser window is big enough or
  to be at the bottom. The div1 doesn't have a static height of course.</p>
  
  <p>This image is how I want to position div2 if the browser window is big</p>
  
  <p><img src="https://i.stack.imgur.com/Ye6dr.png" alt="big window"></p>
  
  <p>The following is how I want div2 to be positioned if the browser window is small.</p>
  
  <p><img src="https://i.stack.imgur.com/ZH2di.png" alt="small window"></p>