CodePen

HTML

            
              

    <ol>
      <li>First</li>
      <li>Second</li>
      <li>Third</li>
    </ol>

            
          
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CSS

            
              ol {
  margin-left:0; 
  padding-left:0; 
  counter-reset:item;
}

ol>li {
  margin-left:0; 
  padding-left:0; 
  counter-increment:item; 
  list-style:none inside;
}

ol>li:before {
  content:counter(item) ".";
  padding-right:0.5em;
}

li:nth-child(odd) {
  background-color: #e3f3d4;
}

            
          
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JS

            
              
            
          
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