A. A css box model is a way of formatting a page's elements and, from the inside out, contains content, padding, border, and margin
A. The margin is this space between the edges of the page and the outside of the border. The padding is the space between the text and the inside of the border.
A. Setting the box-sizing to border-box will take into account the total height and width
A. Padding reads in each input as top, right, bottom, left. padding: 25px 50px will set the top and bottom to 25px and the left and right to 50px