The Webview shows a gray (#ddd) layer on top of the element. I am not sure where "$hyph_shadow" comes from (maybe jQuery?).

Here are the 2 lines of code that are problematic:
$hyph_webkit$hyph_box$hyph_shadow: ['_', "0px 0px ", 10, "px #dddddd"],
box$hyph_shadow: ['_', "0px 0px ", 10, "px #dddddd"],