cheat sheets.

+-----------------------------------------------------+
:                                                     :
:   _______________________________________________   :
:  | _____________________________________________ |  :
:  ||                                             ||  :
:  ||                                             ||  :
:  ||   +-------------------------------------+   ||  :
:  ||   |                                     |   ||  :
:  ||   |      Content (width x height)       |   ||  :
:  ||   |                                     |   ||  :
:  ||   +-------------------------------------+   ||  :
:  ||            Padding (background)             ||  :
:  ||_____________________________________________||  :
:  |___________________Border______________________|  :
:                                                     :
:                Margin (transparent)                 :
+-----------------------------------------------------+

   Area = (width,height) + padding + border + margin