Re: How to disable rgba function
I think you're mis-diagnosing what you're seeing. You obviously didn't include the full styles, as I clearly see a box-shadow in there. In fact I believe what you are actually seeing is the box-shadow shape showing through behind the element -- this is a known bug in PIE: https://github.com/lojjic/PIE/issues/12
If I'm right, then removing the box-shadow should make it appear as you expect (minus the outer shadow of course).