CodePen

HTML

            
              <h1>Rounded inside body</h1>
 

            
          
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CSS

            
              html {
  height:100%;
}
body {
  box-shadow:0px 0px 0px 10px #5bb0ff;
  border:10px solid #5bb0ff;
  box-sizing:border-box;
  text-align: center;
  border-radius:20px;
  background: #fff;
  min-height:100%;
  padding: 20px;
  height:100%;
}
            
          
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JS

            
              
            
          
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999px
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