Strange Blocking

For some reason some of my LINK text has a dark overlay like in the screenshot.  I recently started using a style sheet for all my fonts instead of putting them inside the HTML file so I think I have something wrong.

Thanks

Alan

These are my styles in my CSS

  .stylelinks {

  font-family: Arial;

  color: #983200;

  font-size: 14px;

  font-weight:200;

  background-color:#005100;

}

  a:link {

    color: #983200;

}

  a:hover {

    color: #006600;

}