Forum:Tip identical to cursor

For the mainpagehover class, I would like the vertical-align:middle of the right edge to be identical to wherever your mouse is (as long as it is on the mainpagebutton), how to make it like that? If you don't understand please reply &mdash; [/wiki/User:Sam_Wang S a m ] [/wiki/User_talk:Sam_Wang W a n g ] 12:12, March 19, 2012 (UTC)
 * Can anyone answer this question? &mdash; [/wiki/User:Sam_Wang S a m ] [/wiki/User_talk:Sam_Wang W a n g ] 11:23, March 21, 2012 (UTC)