Support & Tweet Button

We just started with our Hackaton weekend to finish the Episto project.
( http://epis.to )

It is an app to read, write and support open letters..We will probably use these buttons (css3) with every letter, so people can support the open letter by tweeting it..

What do you think of the buttons and the concept? the top button is the normal state and the bottom one is when you've supported the letter already..

Feedback very much appreciated!