How to style input fields and some buttons?

Hi again, one more question. Does anyone know how to style input fields in Parabola (e.g. comment, author, url, search, etc.)? I want to get rid of the “shadow” around the boxes, the color change when focussed and want to modify the size and the font size. How can I do that?

Furthermore, I don’t know how to style buttons with transition effects, e.g. the “submit”-button in comments.

Many thanks in advance ??