CSS Properties

Core Content: Block and inline elements have core content area defined by their properties
Padding: Surrounds the core content giving space before the border, default is none
Border: Colour, width and style can be specified. Default is none
Margin: Distance between this box and the previous and folowing ones.; Margin is transparent
Background: Background and padding of core content specified as a colour or an image

Margin and padding can be defined separately (top, right, bottom, left in that order)
Two elements with bottom and top (vertical) margins will have the two collapsed to one (maximum value of the two)
Total width is width of margin, border, padding and width of core content
Be careful how you define border width if you want precise spacing. Some widths (such as thin) are for the browser to define
Most block-level elements have default margin settings and these may vary
```
* {margin:0; padding:0}
```
will get rid of most of these defaults in most browsers