How to put center kleo button

Hello
I upload the Get connected Page.
I put a desciption with a Kleo Button To make “register” ( how it work in my page )
And a Bp Profil search with a Kleo button “rechercher”

But the second button is not center.
I would like know if we have to enter in the CSS to put Center in the Kleo Button
Or if we can make center in the Kleo Button directly in the backoffice ?

You can see my WebPage here : http://www.le-journal-des-dj-producteurs.com/get-connected-vertical-form/

Thanks you