Design guidelines

There are some restrictions that facebook forces on the websites in terms of design

The buttons cannot be changed, there are only 2 versions in terms of colors and only 3 version in terms of size

Additionally, the logged in users see text underneath the buttons. The color of the text cannot be changed

These are the example buttons including the size they take in the page (in pixels), images are pngs with transparent background

Users logged out of facebook:

Logged in users: