CodePen

HTML

            
              <h1>Heading 1</h1>
<h2>Heading 2</h2>
<h3>Heading 3</h3>

<div class="post">
  <h1>Heading 1</h1>
  <h2>Heading 2</h2>
  <h3>Heading 3</h3>
</div>
            
          
!

CSS

            
              * {
 margin:0;
  padding:0;
  margin-bottom:0.25em;
}
/*
  STYLE
*/
h1 {
 font-size:3em; 
}
h2 {
 font-size:2em; 
}
h3 {
 font-size:1.5em; 
}

.post h1 {
 color:red; 
}
.post h2 {
 color:green; 
}
.post h3 {
 color:blue; 
}
            
          
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JS

            
              
            
          
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