Revert ":first-of-type CSS pseudo-class represents the first sibling of its type in the list of children of its parent element"

This reverts commit 45e2a8b01cc8c1523f725bd9deaa33450b730a05.
Revert "add mouse over effect"

This reverts commit 7a88b78ab63c4c88bd7d34e36eb080953d891dbd.