.related-articles{
    margin-top: 4rem
 }
 .article-header h1{
   position: relative;
 }

.article-header h1:after{ 
   content:'';
   width: 80%;
   height: 2px;
   display: block; 
   margin: 1em auto  ;
   background-color:  rgba(0,0,0,.1); 
}