Cool mobile site Alex! When I tested your site on an iPhone 4, it showed a grey border. I think it’s a phone or browser specific effect that is added to give the touch-user feedback from touching a link.
Here’s a link that talks about that: android - Remove focus overlay-color of webview - Stack Overflow
Try putting this in your custom code:
<style>
a {
-webkit-tap-highlight-color: rgba(0, 0, 0, 0);
}
a:focus {
outline: 0;
border:none;
color: rgba(0, 0, 0, 0);
}
</style>