border

This property applies to all elements and separates margin area (margin) from internal adjustment area (padding). It admits from 1 to 3 values, separated by spaces, and define thickness, style and color. These values apply to all sides : top, right, bottom and left.

Thickness is specified by a value (number, or keyword) in the list : thin , medium, thick.

Style is defined by a keyword (cf below, border-style property).

Color is defined by a keyword (one of the 16 predefined colors).

 border-style

This property defines the border style, from a list of predefined styles (keywords). It accepts from 1 to 4 values, separated by spaces. These values apply in the following order : top, right, bottom, and left. Predefined values are : none, dotted, dashed, solid, double, groove, ridge, inset, outset.

 border-color

This property defines separately the border color, in a 16 predefined color list (keywords). It accepts from 1 to 4 values, separated by spaces. These values apply in the following order : top, right, bottom, and left.

Top, right, bottom and left borders can be separatedly specified with below properties (they accept from 1 to 3 values (thickness, style and color)) :

 border-top
 border-right
 border-bottom
 border-left