Try it Live

​x
 
<!DOCTYPE html>
<html>
  <head>
    <style>
     .main-display {
      border:2px solid green;
      background:green ;
      padding:20px;
      width:300px;
      display:contents;
     }
     
     .contents-val {
      padding:5px;
      background:gold;
      border:2px solid black;
     }
     
     .main-display2 {
      border:2px solid green;
      background:green ;
      padding:20px;
      width:300px;
     }
     
     .contents-val2 {
      padding:5px;
      background:gold;
      border:2px solid black;
     }
    </style>
  </head>
  <body>
    <div class="main-display">
      <div class="contents-val">With display:contents</div>
    </div>
    <br>
    <div class="main-display2">
      <div class="contents-val2">Without display:contents</div>
    </div>
  </body>
</html>
​