The buttons do not light correctly

The buttons do not light correctly when the mouse sits on top of them. This happens in all the buttons of the page (login, logout, new, clear, and so on).

For example:
![image](https://user-images.githubusercontent.com/55830012/75243315-f5acb180-57c9-11ea-922c-8171aee8d1aa.png)
 