For future reference, the following is a an alternative method that avoids having to define border properties (colour, width) more than once and allows declarations similar to those used for margin and padding (as requested).
border: 5px green;
border-style: solid none;
As with margin or padding, border-style is defined in order of top, right, bottom, left. The above case applies a solid border to top and bottom of an element and no border to the left or right of the element.
Using this method avoids creating redundancies in the declaration.