[CSS] Styling Links
a:link {color:#FF0000;} /* unvisited link */
a:visited {color:#00FF00;} /* visited link */
a:hover {color:#FF00FF;} /* mouse over link */
a:active {color:#0000FF;} /* selected link */•a:hover MUST come after a:link and a:visited
•a:active MUST come after a:hover
須按照順序列出，否則沒有效果。