The plugin uses inline styling in HTML Tags and it becomes difficult to override styles using CSS. Just to override a few styles I had to override the complete plugin in WordPress which is not necessary.
I think if you just get rid of the inline styling it will help a lot.
Better still if you can please include some prefixed classes in the input fields rather than just having those generic class names such as "required" it would help select particular element and style it.
The plugin uses inline styling in HTML Tags and it becomes difficult to override styles using CSS. Just to override a few styles I had to override the complete plugin in WordPress which is not necessary.
I think if you just get rid of the inline styling it will help a lot.