Problems displaying digiprove notification on website using Safari

Hi there,

For some strange reason the digiprove plugin icon that is displayed in the notification “copyright secured by digiprove” is completely stretched out when viewing my site (dwarsliggersschrijven.nl) in Safari. I’ve tried to change the element-style display in the style.css code using CSS Editor, but to no avail. I’m running the latest version of digiprove plugin (Copyright Proof v2.15), and use the twenty twelve theme. All other browsers I tested (Firefox, Chrome, IE8) the digiprove notification looks fine, but unfortunately I use Safari as my standard browser. Anyone any ideas, is it a bug specific to Safari or have I done something “wrong” and most importantly can I solve it?
Any suggestions will be greatly appreciated!
Cheers.