Some elements are stacked like blocks. Block level boxes start a new line like pressing return on the
keyboard. Examples include paragraphs, divs and lists.
The other type of element is inline. Inline boxes stay on the same line as the text and other elements
surrounding it.
You can change the size of these boxes by setting the width of the box (sometimes you can use height
too).
Margins, Padding and Borders can help separate these boxes.
These boxes can be nested inside one another. The box that contains another box is called the parent element. The box just inside the parent is the child. There can be many boxes inside of a box.