Add Extra Button on Events Summary Page

Hi Will! I've followed this but I cannot figure out how to change the text colour on the button - at the moment it disappears on hover! I've asked Robo-Will but he didn't get it...'m hoping human Will does! Thanks a lot, Mel

Hi Will! This works great! Is there a way to add a button like this that goes directly to the source link or to the link in the excerpt in a summary block?