CSS

counter-reset ol css

/* counter-reset makes it possible to number elements 
   similarly to an ordered list. First, the counter is
   defined through the counter-reset property and then 
   that counter is incremented using the counter-increment
   property as shown below. 
*/

article {
	counter-reset: article-items; /* initialize the counter */ 
}

section {
	counter-increment: article-items; /* increment counter for every section */
}

section h2::before {
    /* Use counter to number h2 headings of different sections */ 
 	content: counter(article-items) '. ';  
}