CSS to Expand Space Between Text Hyperlink and Its Underline

Is there a way to expand the space between letters and underlines in text-based hyperlinks using CSS?

The CSS I'm planning to use is:

.post-body a {
  text-decoration: underline;
}

My blog is hosted on Blogger and uses the Simple template - http://nickalive.blogspot.com

Thank-you for your time. :)