in your theme’s style.css near line 37. Specifically, the * selects all elements, including the checkboxes and radio buttons in the seamless donations form.
Try removing that style (just the -webkit-appearance line) and see if that does the trick. You may also want to look over the rest of your site after doing so to make sure you’re still happy with the style on everything else.
The check boxes or radio buttons dont show up on my theme. I dont know enough about CSS to try and implement any change hinted at by the above reply! Can you see what is causing the problem and help me fix it? I like the plug in a lot so would like to be able to use it!