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HTML

            
              
            
          
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↑ Insert the most common viewport meta tag

CSS

            
              html,
html *,
html:before,
html:after,
html *:before,
html *:after {
  display: inline-block;
  visibility: visible;
  background: #2B5B89;
  color: #2B5B89;
  border: 1px solid #7FDBFF;
  margin: 1em;
  padding: 1em;
  line-height: 1;
  vertical-align: middle;
  text-align: center;
  animation: sombra 1s infinite;
}
html:before,
html:after,
html *:before,
html *:after {
  content: '';
}
title {
  color: #fff;
}
@keyframes sombra {
  50% {
    box-shadow: 0 0 0 5px rgba(255,255,255,.5) inset;}
}
            
          
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JS

            
              
            
          
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