CSS-only technique to keep vertical rhythm with 1-2 line headings

gistfile1.html

<!--
  Here is a CSS-only technique to keep vertical rhythm even with 
  2-line headings that have an out-of-sync line-height.  Headings 
  with 3 or more lines still break rhythm, but hopefully they are 
  sufficiently uncommon.
-->

<style type="text/css">
  .container {
    width: 400px;
    
    font-size: 16px;
    /* NOTE subsequent lengths are in px purely for demonstration.
     *  Ideally, a CSS preprocessor would help you put them in em. */
    line-height: 24px;
  }
  
  p {
    margin: 24px 0;
  }
  
  h1 {
    font-size: 42px;
    margin: 24px 0;
    
    /* a more reasonable line-height for a heading than 1.5em */
    line-height: 50px;
    
    /* align last line and ::after */
    vertical-align: top; 
    
    /* DEBUG */
    /* background: #fdd; */
  }
  
  h1:first-line {
    /* align first line and ::before */
    vertical-align: bottom;
  }
  
  /**** here's most of the magic ****/
  h1:before, h1:after {
    content: "\feff"; /* zero-width nbsp */
    display: inline-block;
    width: 1px;
    margin-left: -1px;
    
    /* multiple of base line height */
    height: 72px;
    
    /* DEBUG */
    /* background: #ddf; */
  }
</style>


<div class="container">
  <h1>Lorem Ipsum</h1>

  <p>
    Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do 
    eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut 
    enim ad minim veniam, quis nostrud exercitation ullamco laboris 
    nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor 
    in reprehenderit in voluptate velit esse cillum dolore eu fugiat 
    nulla pariatur. Excepteur sint occaecat cupidatat non proident, 
    sunt in culpa qui officia deserunt mollit anim id est laborum.
  </p>
  
  <h1>Lorem Ipsum Lorem Ipsum Lorem Ipsum</h1>
  
  <p>
    Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do  
    eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut 
    enim ad minim veniam, quis nostrud exercitation ullamco laboris 
    nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor 
    in reprehenderit in voluptate velit esse cillum dolore eu fugiat 
    nulla pariatur. Excepteur sint occaecat cupidatat non proident, 
    sunt in culpa qui officia deserunt mollit anim id est laborum.
  </p>
</div>