Hoping someone might be able to help me with a question that has me stumped. The tumblr theme I use at jackjohnbrown.com has an iframe that contains several useful elements that allow readers to share my content, but it also contains one button I'd like to remove--the "tumblr" button in the corner that is shown to any reader not logged into tumblr:

I am able to use
#tumblr_controls {display: none}
in my custom CSS area to hide that, but then I also lose the useful elements that I want to keep. Is there a CSS method that will allow me to remove or hide only the "tumblr" button?

Thanks for any help you can give!