CodePen

HTML

            
                <div class="diamond"></div>

            
          
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CSS

            
              
.diamond {
  width:250px;
  height:250px;
  background:darkblue;
  margin:80px auto;
  border: 5px solid white;
  outline: 5px solid gold;
  transform:rotate(-45deg);
}

            
          
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JavaScript

            
              
            
          
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999px
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