<div class="container-main-pricing alert-dark"> <h3>Rear Setback</h3> <hr style="width:50%;margin-left:auto;margin-right:auto;"> <p><?php echo $cost; ?></p> </div> code example

Example: which is right or in html

<hr> <!--   it represents a horizontal line break, in HTML4.0 we use <hr>, 
            in XHTML1.0 we use <hr/>,  in HTML5(which is the current version of 
            HTML) we can use both <hr> and <hr/>    
       -->