L!n34B4j0L05P057

h3.post-title, .comments h4 {
font: $(post.title.font);
margin: .75em 0 0;
text-align: center;

And I added the line below to the bottom of what is highlighted in yellow. And it worked! Remember to close the bracket, which is below it.
 

border-bottom:2px dashed #CE0000;
}

h3.post-title, .comments h4 {
font: $(post.title.font);
margin: .75em 0 0;
text-align: center;

border-bottom:2px dashed #CE0000;

}