reCAPTCHA box not being aligned correctly

Question

I can't get to align correctly the reCAPTCHA form on my registration page. Even if the div it is contained in has text-align set to center, it is displayed on the left of the page:
While if I change its align via JavaScript (document.getElementById("recaptcha_widget_div").align = "right") it works correctly (screenshot taken in the middle of the page):

What am I doing wrong?

Edit: here's a fiddle with the div and the entire CSS called in the page.

Answer 1

You need this css rule:

#recaptcha_area { margin: auto}