title: what's the difference between window size and viewport size
body: <p>I found a good article explains the concept of view port:
  <a href="https://www.quirksmode.org/mobile/viewports.html" rel="nofollow noreferrer">https://www.quirksmode.org/mobile/viewports.html</a></p>
  
  <p>But I'm still a little bit confused with the differences between  window size and viewport size, 
  <strong>Window Size:</strong></p>
  
  <p><a href="https://i.stack.imgur.com/dFd8D.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/dFd8D.png" alt="enter image description here"></a> </p>
  
  <p><strong>Viewport Size:</strong></p>
  
  <p><a href="https://i.stack.imgur.com/4QdvO.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/4QdvO.png" alt="enter image description here"></a></p>
  
  <p>aren't they the same thing?</p>