It is the same with all those things. Basically Border, Background, etc. are just summaries of the different subproperties. So border consists out of border-color, border-bottom/left/right/top, border-style and many more, where as the different borders (top, etc) are also just summaries of their subproperties. You can but don't have to fill in every single attribute of that propertie, that is basically the use of those things. Normally it is not required to use such things, only when it comes to specific things like margin-bottom, even though you could set "margin: top right left bottom;" or margin: "top&bottom left&right".