Why is it my ‘:hover’ declaration for links does not work ?
Assuming you have already checked that your style sheet declarations do conform to correct CSS syntax, it could be that you have overlooked the importance of a correct order of style declarations for links.
The CSS2 specification makes this following note on the importance of placing the dynamic pseudo-classes ‘:hover’ and ‘:active’ in correct positions in a list of style declarations.
Note that the ‘a:hover’ must be placed after the ‘a:link’ and ‘a:visited’ rules, since otherwise the cascading rules will hide the ‘color’ property of the ‘a:hover’ rule.
Similarly, because ‘a:active’ is placed after ‘a:hover’, the active color will apply when the user both activates and hovers over the ‘a’ element.