add this code to the Extra CSS (preferences--common options--look&feel)
Code:
a:link {color: whatever color you want}
these are other color style options
links can be displayed in different ways
Code:
a:visited {color:#00FF00;} /* visited link */
a:hover {color:#FF00FF;} /* mouse over link */
a:active {color:#0000FF;} /* selected link */