<div class="parent">
    <div class="line"></div>
    <p>Viewport Width: <span class="viewport"></span></p>
    <div class="line"></div>
  </div>
  
  <div class="rectangle">
    <p>Box Width: <span class="box-width"></span></p>
    <p>Box Height: <span class="box-height"></span></p>
    <p>Font Size: <span class="box-font"></span></p>
  </div>