Ghost link color (Casper)

I realized that Casper doesn’t let to change the link colors of the link from the options. You must go through the code. It might be a nice addition for the future updates of Ghost, since this is something very vital for usability.

Also, the default link color is the same of the text for the Casper theme, and makes the links almost invisible to the user.

Can I ask what is the code I should inject in the CSS in order to change the colors. If I use something like this, is it good enough or should I user a different code?

a:link {
  color: blue;

a:visited {
  color: purple;