Button Doesn't show up

I’m not sure what the deal is. I might be having a CSS issue but I can’t see anything there. I tried editing the button’s css but no luck.

There is a submit button at the bottom of this page, but you can’t see it.

learnenglish20.com/register

any help would be very much appreciated.

https://ww.wp.xz.cn/plugins/social-connect/